idk

.dockerignore

@@ -0,0 +1,4 @@
+target
+build
+.git
+*.bak

.gitignore

@@ -1,2 +1,4 @@
 /target
 /build
+*.bak
+*.lock

Cargo.toml

@@ -1,15 +1,23 @@
 [package]
-name = "builder"
+name = "distro"
 version = "0.1.0"
 edition = "2024"
+license = "MIT"
 
 [dependencies]
-allocative = "0.3.4"
-anyhow = "1.0.102"
-clap = { version = "4.6.1", features = ["derive"] }
-either = "1.16.0"
-petgraph = "0.8.3"
-smallvec = "1.15.1"
-starlark = "0.13.0"
-starlark_derive = "0.13.0"
-thiserror = "2.0.18"
+anyhow = "1.0"
+clap = { version = "4.5", features = ["derive"] }
+hex = "0.4"
+reqwest = { version = "0.12", default-features = false, features = [
+    "blocking",
+    "rustls-tls",
+] }
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+sha2 = "0.10"
+shell-escape = "0.1"
+starlark = "0.13"
+starlark_derive = "0.13"
+allocative = "0.3"
+tempfile = "3.10"
+walkdir = "2.5"

Dockerfile

@@ -0,0 +1,40 @@
+FROM alpine:edge
+
+RUN apk upgrade --no-cache && apk add --no-cache \
+    alpine-sdk \
+    apk-tools \
+    autoconf \
+    automake \
+    bash \
+    bc \
+    bison \
+    bzip2 \
+    ca-certificates \
+    cmake \
+    coreutils \
+    curl \
+    file \
+    findutils \
+    flex \
+    gettext-dev \
+    git \
+    gzip \
+    elfutils-dev \
+    gmp-dev \
+    mpfr-dev \
+    mpc1-dev \
+    libtool \
+    linux-headers \
+    meson \
+    ninja \
+    openssl \
+    openssl-dev \
+    patch \
+    pkgconf \
+    python3 \
+    tar \
+    texinfo \
+    xz \
+    zstd
+
+WORKDIR /work

LICENSE

@@ -0,0 +1,18 @@
+MIT License
+
+Copyright (c) 2026 marv7000
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of this software and 
+associated documentation files (the "Software"), to deal in the Software without restriction, including 
+without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 
+copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the 
+following conditions:
+
+The above copyright notice and this permission notice shall be included in all copies or substantial 
+portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT 
+LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO 
+EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER 
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 
+USE OR OTHER DEALINGS IN THE SOFTWARE.

config.star

@@ -1,64 +1,36 @@
+container_runtime = "podman"
+container_image = "local/distro-builder:latest"
+container_dockerfile = "Dockerfile"
+
 arch = "x86_64"
-libc = "glibc"
+libc = "musl"
 
-if libc == "glibc":
-  env = "gnu"
-elif libc == "musl":
-  env = "musl"
-else:
-  fail(f"Unknown libc: {libc}")
+host_cflags = "-O2 -pipe"
+host_cxxflags = ""
+host_ldflags = "-Wl,-O1 -Wl,--sort-common -Wl,--as-needed"
 
-prefix = path("/usr")
-
-host_cflags = ["-O2", "-pipe"]
-host_cxxflags = host_cflags + []
-host_ldflags = ["-Wl,-O1", "-Wl,--sort-common", "-Wl,--as-needed"]
-
-target_cflags = host_cflags + []
-target_cxxflags = host_cxxflags + []
-target_ldflags = host_ldflags + ["-Wl,-z,now"]
+target_cflags = host_cflags
+target_cxxflags = host_cxxflags
+target_ldflags = host_ldflags + " -Wl,-z,now"
 
 if arch == "x86_64":
-  flags = [
-    "-march=x86-64-v3",
-    "-mtune=generic",
-    "-fstack-clash-protection",
-    "-fstack-protector-strong",
-    "-fcf-protection",
-  ]
+    flags = " -march=x86-64-v3 -mtune=generic -fstack-clash-protection -fstack-protector-strong -fcf-protection"
 
-  target_cflags += flags
-  target_cxxflags += flags
-  target_ldflags += ["-Wl,-z,pack-relative-relocs"]
+    target_cflags += flags
+    target_cxxflags += flags
+    target_ldflags += " -Wl,-z,pack-relative-relocs"
 
-config(
-  arch = arch,
-  recipes_dir = path("./recipes"),
-  host_recipes_dir = path("./host-recipes"),
-  container = podman(
-    image = "local/builder:latest",
-    dockerfile = path("./Dockerfile"),
-  ),
+options = dict(
+    target_arch = arch,
+    target_triple = f"{arch}-linux-{libc}",
 
-  target_arch = arch,
-  target_triple = f"{arch}-orchid-linux-{env}",
+    host_cflags = host_cflags,
+    host_cxxflags = host_cxxflags,
+    host_ldflags = host_ldflags,
 
-  libc = libc,
+    cflags = target_cflags,
+    cxxflags = target_cxxflags,
+    ldflags = target_ldflags,
 
-  prefix = prefix,
-  bindir = prefix / "bin",
-  sbindir = prefix / "bin",
-  libdir = prefix / "lib",
-  libexecdir = prefix / "libexec",
-  includedir = prefix / "include",
-  sysconfdir = path("/etc"),
-  localstatedir = path("/var"),
-
-  host_cflags = " ".join(host_cflags),
-  host_cxxflags = " ".join(host_cxxflags),
-  host_ldflags = " ".join(host_ldflags),
-
-  cflags = " ".join(target_cflags),
-  cxxflags = " ".join(target_cxxflags),
-  ldflags = " ".join(target_ldflags),
+    libc = libc,
 )

host-recipes/binutils.star

@@ -1,39 +1,39 @@
 version = "2.46.0"
 revision = 1
 metadata = meta(
-  description = "GNU binutils cross-compiled for the target triple",
-  license = "GPL-3.0-or-later",
+    description = "GNU binutils cross-compiled for the target triple",
+    license = "GPL-3.0-or-later",
 )
-source = tarball(
-  url = f"https://ftp.gnu.org/gnu/binutils/binutils-{version}.tar.xz",
-  sha256 = "d75a94f4d73e7a4086f7513e67e439e8fcdcbb726ffe63f4661744e6256b2cf2",
-  strip_components = 1,
+source = tarball_source(
+    url = "https://ftp.gnu.org/gnu/binutils/binutils-" + version + ".tar.xz",
+    sha256 = "d75a94f4d73e7a4086f7513e67e439e8fcdcbb726ffe63f4661744e6256b2cf2",
+    strip_components = 1,
 )
 
 def configure(ctx):
-  ctx.run(
-    ctx.source_dir / "configure",
-    "--prefix=" + options.prefix,
-    "--target=" + options.target_triple,
-    "--with-sysroot=" + ctx.sysroot_dir,
-    "--with-pic",
-    "--enable-cet",
-    "--enable-default-execstack=no",
-    "--enable-deterministic-archives",
-    "--enable-ld=default",
-    "--enable-new-dtags",
-    "--enable-plugins",
-    "--enable-relro",
-    "--enable-separate-code",
-    "--enable-threads",
-    "--disable-nls",
-    "--disable-werror",
-    # gprofng's libcollector relies on glibc-specific internals.
-    "--disable-gprofng",
-  env = {
-    "CFLAGS": options.host_cflags,
-    "CXXFLAGS": options.host_cxxflags,
-    "LDFLAGS": options.host_ldflags,
-  })
+    ctx.run([
+        ctx.source_dir + "/configure",
+        "--prefix=" + ctx.prefix,
+        "--target=" + options.target_triple,
+        "--with-sysroot=" + ctx.sysroot,
+        "--with-pic",
+        "--enable-cet",
+        "--enable-default-execstack=no",
+        "--enable-deterministic-archives",
+        "--enable-ld=default",
+        "--enable-new-dtags",
+        "--enable-plugins",
+        "--enable-relro",
+        "--enable-separate-code",
+        "--enable-threads",
+        # gprofng's libcollector does not build against musl.
+        "--disable-gprofng",
+        "--disable-nls",
+        "--disable-werror",
+    ], env = {
+        "CFLAGS": options.host_cflags,
+        "CXXFLAGS": options.host_cxxflags,
+        "LDFLAGS": options.host_ldflags,
+    })
 
 _, build, install = autotools()

host-recipes/gcc-bootstrap.star

@@ -0,0 +1,47 @@
+version = "16.1.0"
+revision = 1
+metadata = meta(
+    description = "GNU GCC cross-compiler (bootstrap stage, C/C++ only)",
+    license = "GPL-3.0-or-later",
+)
+source = tarball_source(
+    url = f"https://ftp.gnu.org/gnu/gcc/gcc-{version}/gcc-{version}.tar.xz",
+    sha256 = "50efb4d94c3397aff3b0d61a5abd748b4dd31d9d3f2ab7be05b171d36a510f79",
+    strip_components = 1,
+)
+host_deps = ["binutils"]
+
+def configure(ctx):
+    ctx.run([
+        ctx.source_dir + "/configure",
+        "--target=" + options.target_triple,
+        "--prefix=" + ctx.prefix,
+        "--with-sysroot=" + ctx.sysroot,
+        "--without-headers",
+        "--with-newlib",
+        "--enable-languages=c,c++",
+        "--enable-default-pie",
+        "--enable-default-ssp",
+        "--disable-nls",
+        "--disable-shared",
+        "--disable-threads",
+        "--disable-libssp",
+        "--disable-libgomp",
+        "--disable-libquadmath",
+        "--disable-libatomic",
+        "--disable-libvtv",
+        "--disable-multilib",
+    ], env = {
+        "CFLAGS": options.host_cflags,
+        "CXXFLAGS": options.host_cxxflags,
+        "LDFLAGS": options.host_ldflags,
+    })
+
+def build(ctx):
+    jobs = "-j" + str(ctx.jobs)
+    ctx.run(["make", jobs, "all-gcc"])
+    ctx.run(["make", jobs, "all-target-libgcc"])
+
+def install(ctx, pkg):
+    ctx.run(["make", "install-gcc"], env = {"DESTDIR": pkg.dest_dir})
+    ctx.run(["make", "install-target-libgcc"], env = {"DESTDIR": pkg.dest_dir})

lib/common.star

@@ -0,0 +1,37 @@
+# Commonly used helpers.
+
+def autotools_configure(ctx, extra_args = [], extra_env = {}):
+    env = {
+        "CFLAGS": options.cflags,
+        "CXXFLAGS": options.cxxflags,
+        "LDFLAGS": options.ldflags,
+    }
+    env.update(extra_env)
+    ctx.run([
+        ctx.source_dir + "/configure",
+        "--host=" + options.target_triple,
+        "--with-sysroot=" + ctx.sysroot,
+        "--prefix=" + ctx.prefix,
+        "--sysconfdir=/etc",
+        "--localstatedir=/var",
+        "--bindir=" + ctx.prefix + "/bin",
+        "--sbindir=" + ctx.prefix + "/bin",
+        "--libdir=" + ctx.prefix + "/lib",
+        "--disable-static",
+        "--enable-shared",
+    ] + extra_args, env = env)
+
+def autotools_build(ctx, extra_args = []):
+    ctx.run(["make", "-j" + str(ctx.jobs)] + extra_args)
+
+def autotools_install(ctx, pkg, extra_args = []):
+    ctx.run(["make", "install"] + extra_args, env = {"DESTDIR": pkg.dest_dir})
+
+def autotools(configure_args = [], configure_env = {}, build_args = [], install_args = []):
+    def _configure(ctx):
+        autotools_configure(ctx, extra_args = configure_args, extra_env = configure_env)
+    def _build(ctx):
+        autotools_build(ctx, extra_args = build_args)
+    def _install(ctx, pkg):
+        autotools_install(ctx, pkg, extra_args = install_args)
+    return _configure, _build, _install

recipes/limine.star

@@ -0,0 +1,25 @@
+version = "12.2.0"
+revision = 1
+metadata = meta(
+    description = "Modern, secure, portable, multiprotocol bootloader and boot manager",
+    license = "BSD-2-Clause",
+)
+source = tarball_source(
+    url = f"https://github.com/Limine-Bootloader/Limine/releases/download/v{version}/limine-{version}.tar.gz",
+    sha256 = "db8a119878cfeead63c0a78236c577c40539c5759496950ea0ed32a6cf567865",
+    strip_components = 1,
+)
+host_deps = ["binutils", "gcc"]
+deps = [options.libc]
+subpackages = [
+    subpackage(
+        name = "limine-bios",
+    ),
+]
+
+configure, build, install = autotools(configure_env = {
+    "TOOLCHAIN_FOR_TARGET": options.target_triple + "-",
+    "LD_FOR_TARGET": options.target_triple + "-" + "ld",
+    "OBJCOPY_FOR_TARGET": options.target_triple + "-" + "objcopy",
+    "OBJDUMP_FOR_TARGET": options.target_triple + "-" + "objdump",
+})

recipes/linux-headers.star

@@ -1,20 +1,20 @@
 version = "7.0.9"
 revision = 1
 metadata = meta(
-  description = "Linux kernel headers for userspace development",
-  license = "GPL-2.0-only",
+    description = "Linux kernel headers for userspace development",
+    license = "GPL-2.0-only",
 )
-source = tarball(
-  url = f"https://cdn.kernel.org/pub/linux/kernel/v7.x/linux-{version}.tar.xz",
-  sha256 = "ac07acdf76cf4621cc5187a2670270a1a699533c8a6b225e4878c416ad83f1c4",
-  strip_components = 1,
+source = tarball_source(
+    url = f"https://cdn.kernel.org/pub/linux/kernel/v7.x/linux-{version}.tar.xz",
+    sha256 = "ac07acdf76cf4621cc5187a2670270a1a699533c8a6b225e4878c416ad83f1c4",
+    strip_components = 1,
 )
 
 def build(ctx):
-  ctx.run("cp", "-rp", ctx.source_dir / ".", ctx.build_dir)
-  ctx.run("make", "headers_install", "ARCH=" + options.target_arch)
-  ctx.run("find", ctx.build_dir / "usr" / "include", "-type", "f", "!", "-name", "*.h", "-delete")
+    ctx.run(["cp", "-rp", ctx.source_dir + "/.", ctx.build_dir])
+    ctx.run(["make", "headers_install", "ARCH=" + options.target_arch])
+    ctx.run(["find", ctx.build_dir + "/usr/include", "-type", "f", "!", "-name", "*.h", "-delete"])
 
-def install(ctx):
-  ctx.run("mkdir", "-p", ctx.dest_dir / options.prefix)
-  ctx.run("cp", "-rp", ctx.build_dir / "usr" / "include", ctx.dest_dir / options.prefix)
+def install(ctx, pkg):
+    ctx.run(["mkdir", "-p", pkg.dest_dir + ctx.prefix])
+    ctx.run(["cp", "-rp", ctx.build_dir + "/usr/include", pkg.dest_dir + ctx.prefix])

recipes/linux.star.old

@@ -0,0 +1,37 @@
+name = "linux"
+version = "7.0.9"
+revision = 1
+description = "Linux kernel"
+license = "GPL-2.0-only"
+
+source = {
+    "url": f"https://cdn.kernel.org/pub/linux/kernel/v7.x/linux-{version}.tar.xz",
+    "sha256": "ac07acdf76cf4621cc5187a2670270a1a699533c8a6b225e4878c416ad83f1c4",
+    "strip_components": 1,
+}
+
+host_deps = ["binutils", "gcc"]
+
+def _make_args(ctx, *args):
+    result = [
+        "make",
+        "-C", ctx.source_dir,
+        "O=" + ctx.build_dir,
+        "ARCH=x86_64",
+        "CROSS_COMPILE=" + OPTIONS.target_triple + "-",
+        "-j" + str(ctx.jobs),
+    ]
+    result.extend(args)
+    return result
+
+def configure(ctx):
+    ctx.run(_make_args(ctx, "defconfig"))
+
+def build(ctx):
+    ctx.run(_make_args(ctx, "bzImage"))
+
+def install(ctx, pkg):
+    ctx.install(
+        ctx.build_dir + "/arch/x86/boot/bzImage",
+        pkg.destdir + "/boot/vmlinuz-" + version,
+    )

recipes/musl.star

@@ -0,0 +1,26 @@
+version = "1.2.6"
+revision = 1
+metadata = meta(
+    description = "Small, standards-conformant implementation of libc",
+    license = "MIT",
+)
+source = tarball_source(
+    url = f"https://musl.libc.org/releases/musl-{version}.tar.gz",
+    sha256 = "d585fd3b613c66151fc3249e8ed44f77020cb5e6c1e635a616d3f9f82460512a",
+    strip_components = 1,
+)
+host_deps = ["binutils", "gcc-bootstrap"]
+
+def configure(ctx):
+    ctx.run([
+        ctx.source_dir + "/configure",
+        "--target=" + options.target_triple,
+        "--prefix=" + ctx.prefix,
+        "--syslibdir=/lib",
+    ], env = {
+        "CC": options.target_triple + "-gcc",
+        "CFLAGS": options.cflags,
+        "LDFLAGS": options.ldflags,
+    })
+
+_, build, install = autotools()

src/builder.rs

@@ -0,0 +1,905 @@
+use std::{
+    cell::RefCell,
+    collections::{BTreeSet, VecDeque},
+    fs,
+    io::Write,
+    path::{Path, PathBuf},
+    process::{Command, Stdio},
+    rc::Rc,
+    thread,
+    time::{SystemTime, UNIX_EPOCH},
+};
+
+use anyhow::{Context, bail};
+use sha2::{Digest, Sha256};
+use starlark::values::OwnedFrozenValue;
+
+use crate::{
+    config::Config,
+    container::{Container, Mount},
+    graph::{TaskId, TaskPlan, TaskPlanner, task_recipe_slug},
+    layout::Layout,
+    log,
+    phase::{
+        self, PackageContext, PhaseArg, PhaseContext, PhaseRuntime, PhaseRuntimeGuard, SourceDir,
+    },
+    recipe::{GitSource, OutputPackage, Recipe, RecipeKind, RecipeSet, Source},
+};
+
+#[derive(Debug)]
+pub struct Builder {
+    root: PathBuf,
+    config: Config,
+    container_ready: bool,
+}
+
+impl Builder {
+    pub fn new(root: PathBuf, config: Config) -> Self {
+        Self {
+            root,
+            config,
+            container_ready: false,
+        }
+    }
+
+    pub fn build(
+        &mut self,
+        recipes: &RecipeSet,
+        requested: &[String],
+        rebuild: bool,
+        dry_run: bool,
+    ) -> anyhow::Result<()> {
+        let plan = TaskPlanner::new(&self.root, &self.config.arch, recipes)
+            .build_plan(requested, rebuild)?;
+        self.print_plan(&plan);
+        if dry_run {
+            return Ok(());
+        }
+        self.execute_plan(recipes, &plan)
+    }
+
+    pub fn fetch(
+        &mut self,
+        recipes: &RecipeSet,
+        requested: &[String],
+        dry_run: bool,
+    ) -> anyhow::Result<()> {
+        let plan =
+            TaskPlanner::new(&self.root, &self.config.arch, recipes).fetch_plan(requested)?;
+        self.print_plan(&plan);
+        if dry_run {
+            return Ok(());
+        }
+        self.execute_plan(recipes, &plan)
+    }
+
+    pub fn ensure_container_ready(&mut self) -> anyhow::Result<()> {
+        if !self.container_ready {
+            self.ensure_container_image(&self.abs_config_path(&self.config.container_dockerfile))?;
+            self.container_ready = true;
+        }
+
+        Ok(())
+    }
+
+    fn execute_plan(&mut self, recipes: &RecipeSet, plan: &TaskPlan) -> anyhow::Result<()> {
+        if plan.is_empty() {
+            return Ok(());
+        }
+
+        let mut active: Option<ActiveContainer> = None;
+
+        for task in plan.order() {
+            let recipe_slug = task_recipe_slug(task, recipes)?;
+
+            if let Some(current) = active.as_ref() {
+                if current.recipe_key != recipe_slug {
+                    active = None;
+                }
+            }
+
+            if task_needs_container(task) && active.is_none() {
+                self.ensure_container_ready()?;
+                active = Some(self.start_recipe_container(recipes, &recipe_slug)?);
+            }
+
+            let layout = Layout::new(&self.root, &self.config.arch);
+            self.run_task(&layout, recipes, task, active.as_ref())?;
+        }
+
+        Ok(())
+    }
+
+    fn run_task(
+        &self,
+        layout: &Layout<'_>,
+        recipes: &RecipeSet,
+        task: &TaskId,
+        active: Option<&ActiveContainer>,
+    ) -> anyhow::Result<()> {
+        match task {
+            TaskId::FetchSources(key) => {
+                let recipe = recipes.recipe(key)?;
+                self.task_fetch_sources(layout, recipe)
+            }
+            TaskId::PrepareSources(key) => {
+                let recipe = recipes.recipe(key)?;
+                self.task_prepare_sources(layout, recipe)
+            }
+            TaskId::ConfigureRecipe(key) => {
+                let recipe = recipes.recipe(key)?;
+                let active = active.expect("configure task requires an active container");
+                self.task_configure(layout, recipe, active)
+            }
+            TaskId::BuildRecipe(key) => {
+                let recipe = recipes.recipe(key)?;
+                let active = active.expect("build task requires an active container");
+                self.task_build(layout, recipe, active)
+            }
+            TaskId::InstallPackageFiles(output_key) => {
+                let output = recipes.output(output_key)?;
+                let recipe = recipes.recipe(output.recipe())?;
+                let active = active.expect("install task requires an active container");
+                self.task_install_package(layout, recipe, output, active)
+            }
+            TaskId::ProduceApk(output_key) => {
+                let output = recipes.output(output_key)?;
+                let recipe = recipes.recipe(output.recipe())?;
+                let active = active.expect("apk task requires an active container");
+                self.task_produce_apk(layout, recipe, output, active)
+            }
+            TaskId::InstallHostRecipe(key) => {
+                let recipe = recipes.recipe(key)?;
+                let active = active.expect("host install task requires an active container");
+                self.task_install_host(layout, recipe, active)
+            }
+        }
+    }
+
+    fn task_fetch_sources(&self, layout: &Layout<'_>, recipe: &Recipe) -> anyhow::Result<()> {
+        fs::create_dir_all(layout.source_cache_dir())?;
+        for (name, source) in recipe.sources().entries() {
+            let label = name.unwrap_or("source");
+            if !source.is_unknown_cache_key()
+                && layout.source_cache_path(source.cache_key()).exists()
+            {
+                log::skip("fetch", &format!("{} ({})", recipe.key(), label));
+                continue;
+            }
+            log::step(
+                "fetch",
+                &format!("{} ({}) from {}", recipe.key(), label, source.url()),
+            );
+            match source {
+                Source::Tarball(_) => self.fetch_tarball(layout, recipe, source)?,
+                Source::Git(git) => self.fetch_git(layout, recipe, git)?,
+            }
+        }
+        Ok(())
+    }
+
+    fn fetch_tarball(
+        &self,
+        layout: &Layout<'_>,
+        recipe: &Recipe,
+        source: &Source,
+    ) -> anyhow::Result<()> {
+        let url = source.url();
+        let expected = source.cache_key().to_owned();
+        let unknown = source.is_unknown_cache_key();
+
+        let client = reqwest::blocking::Client::builder()
+            .user_agent("distro-builder")
+            .build()
+            .context("building HTTP client")?;
+        let mut response = client
+            .get(url)
+            .send()
+            .with_context(|| format!("downloading {url}"))?
+            .error_for_status()
+            .with_context(|| format!("downloading {url}"))?;
+
+        let cache_dir = layout.source_cache_dir();
+        fs::create_dir_all(&cache_dir)?;
+        let mut tmp = tempfile::NamedTempFile::new_in(&cache_dir)
+            .with_context(|| format!("creating temp file in {}", cache_dir.display()))?;
+        let mut hasher = Sha256::new();
+        let mut buf = [0u8; 64 * 1024];
+        loop {
+            let n = std::io::Read::read(&mut response, &mut buf)
+                .with_context(|| format!("reading response body for {url}"))?;
+            if n == 0 {
+                break;
+            }
+            hasher.update(&buf[..n]);
+            tmp.write_all(&buf[..n])?;
+        }
+        tmp.flush()?;
+        let hash = hex::encode(hasher.finalize());
+
+        if unknown {
+            log::info(
+                "fetch",
+                &format!("{}: computed sha256 = {hash}", recipe.key()),
+            );
+        } else if hash != expected {
+            bail!("sha256 mismatch for {url}: expected {expected}, got {hash}");
+        }
+
+        let final_path = layout.source_cache_path(&hash);
+        if !final_path.exists() {
+            tmp.persist(&final_path).with_context(|| {
+                format!("renaming downloaded archive to {}", final_path.display())
+            })?;
+        }
+
+        if unknown {
+            bail!(
+                "{}: source sha256 is unknown; update the recipe with sha256 = \"{hash}\"",
+                recipe.key()
+            );
+        }
+        Ok(())
+    }
+
+    fn fetch_git(
+        &self,
+        layout: &Layout<'_>,
+        recipe: &Recipe,
+        source: &GitSource,
+    ) -> anyhow::Result<()> {
+        let url = source.url();
+        let commit = source.commit();
+        let unknown = matches!(commit, "?" | "???");
+
+        let cache_dir = layout.source_cache_dir();
+        fs::create_dir_all(&cache_dir)?;
+        let tmp = tempfile::tempdir_in(&cache_dir)?;
+        let work = tmp.path().join("repo");
+
+        let status = Command::new("git")
+            .arg("clone")
+            .arg("--bare")
+            .arg(url)
+            .arg(&work)
+            .status()
+            .with_context(|| format!("spawning git clone {url}"))?;
+        if !status.success() {
+            bail!("git clone failed for {url} with {status}");
+        }
+
+        let rev = if unknown {
+            let out = Command::new("git")
+                .arg("-C")
+                .arg(&work)
+                .arg("rev-parse")
+                .arg("HEAD")
+                .output()
+                .context("spawning git rev-parse HEAD")?;
+            if !out.status.success() {
+                bail!("git rev-parse HEAD failed with {}", out.status);
+            }
+            let rev = String::from_utf8(out.stdout)?.trim().to_owned();
+            log::info(
+                "fetch",
+                &format!("{}: resolved git HEAD = {rev}", recipe.key()),
+            );
+            rev
+        } else {
+            let status = Command::new("git")
+                .arg("-C")
+                .arg(&work)
+                .arg("cat-file")
+                .arg("-e")
+                .arg(commit)
+                .status()
+                .context("spawning git cat-file")?;
+            if !status.success() {
+                bail!("commit {commit} not found in {url}");
+            }
+            commit.to_owned()
+        };
+
+        let final_path = layout.source_cache_path(&rev);
+        if !final_path.exists() {
+            fs::rename(&work, &final_path).with_context(|| {
+                format!(
+                    "moving git clone to {} from {}",
+                    final_path.display(),
+                    work.display()
+                )
+            })?;
+        }
+
+        if unknown {
+            bail!(
+                "{}: source commit is unknown; update the recipe with commit = \"{rev}\"",
+                recipe.key()
+            );
+        }
+        Ok(())
+    }
+
+    fn task_prepare_sources(&self, layout: &Layout<'_>, recipe: &Recipe) -> anyhow::Result<()> {
+        log::step("prepare", &recipe.key());
+        let src = layout.source_workdir(recipe);
+        if src.exists() {
+            fs::remove_dir_all(&src).with_context(|| format!("clearing {}", src.display()))?;
+        }
+        fs::create_dir_all(&src)?;
+        let build = layout.build_workdir(recipe);
+        if build.exists() {
+            fs::remove_dir_all(&build).with_context(|| format!("clearing {}", build.display()))?;
+        }
+        fs::create_dir_all(&build)?;
+
+        for (name, source) in recipe.sources().entries() {
+            if source.is_unknown_cache_key() {
+                bail!(
+                    "source for {} has an unknown cache key; run `distro fetch` first",
+                    recipe.key()
+                );
+            }
+            let cache_path = layout.source_cache_path(source.cache_key());
+            if !cache_path.exists() {
+                bail!(
+                    "missing cached source for {} at {}",
+                    recipe.key(),
+                    cache_path.display()
+                );
+            }
+            let dst = match name {
+                None => src.clone(),
+                Some(named) => {
+                    let dst = src.join(named);
+                    fs::create_dir_all(&dst)?;
+                    dst
+                }
+            };
+            match source {
+                Source::Tarball(tar) => {
+                    let mut cmd = Command::new("tar");
+                    cmd.arg("-xf").arg(&cache_path);
+                    if tar.strip_components() > 0 {
+                        cmd.arg(format!("--strip-components={}", tar.strip_components()));
+                    }
+                    cmd.arg("-C").arg(&dst);
+                    let status = cmd
+                        .status()
+                        .with_context(|| format!("spawning tar -xf {}", cache_path.display()))?;
+                    if !status.success() {
+                        bail!(
+                            "tar extraction of {} failed with {status}",
+                            cache_path.display()
+                        );
+                    }
+                }
+                Source::Git(git) => {
+                    let status = Command::new("git")
+                        .arg("clone")
+                        .arg(&cache_path)
+                        .arg(&dst)
+                        .status()
+                        .context("spawning git clone from cache")?;
+                    if !status.success() {
+                        bail!("git clone from cache failed with {status}");
+                    }
+                    let status = Command::new("git")
+                        .arg("-C")
+                        .arg(&dst)
+                        .arg("checkout")
+                        .arg(git.commit())
+                        .status()
+                        .context("spawning git checkout")?;
+                    if !status.success() {
+                        bail!("git checkout {} failed with {status}", git.commit());
+                    }
+                }
+            }
+        }
+
+        let version_stamp = layout.source_stamp(recipe, "version");
+        fs::create_dir_all(version_stamp.parent().unwrap())?;
+        fs::write(
+            &version_stamp,
+            format!("{}-r{}", recipe.version(), recipe.revision()),
+        )?;
+
+        if layout.recipe_has_patches(recipe)? {
+            log::skip(
+                "patches",
+                &format!("{}: patch application not implemented", recipe.key()),
+            );
+            fs::write(layout.source_stamp(recipe, "patched"), b"skipped")?;
+        }
+
+        Ok(())
+    }
+
+    fn task_configure(
+        &self,
+        layout: &Layout<'_>,
+        recipe: &Recipe,
+        active: &ActiveContainer,
+    ) -> anyhow::Result<()> {
+        log::step("configure", &recipe.key());
+        if let Some(func) = recipe.phases().configure() {
+            let ctx = PhaseContext::new(
+                source_dir_for(recipe),
+                prefix_for(recipe.kind()),
+                default_jobs(),
+            );
+            self.invoke_with_runtime(active, &[PhaseArg::Ctx(ctx)], func)?;
+        }
+        self.write_recipe_stamp(layout, recipe, "configure")
+    }
+
+    fn task_build(
+        &self,
+        layout: &Layout<'_>,
+        recipe: &Recipe,
+        active: &ActiveContainer,
+    ) -> anyhow::Result<()> {
+        log::step("build", &recipe.key());
+        let ctx = PhaseContext::new(
+            source_dir_for(recipe),
+            prefix_for(recipe.kind()),
+            default_jobs(),
+        );
+        self.invoke_with_runtime(active, &[PhaseArg::Ctx(ctx)], recipe.phases().build())?;
+        self.write_recipe_stamp(layout, recipe, "build")
+    }
+
+    fn task_install_package(
+        &self,
+        layout: &Layout<'_>,
+        recipe: &Recipe,
+        output: &OutputPackage,
+        active: &ActiveContainer,
+    ) -> anyhow::Result<()> {
+        log::step("install", &output.key());
+        let dest = format!("/dest/{}", output.name());
+        active.container.borrow().exec(
+            &["mkdir".to_owned(), "-p".to_owned(), dest.clone()],
+            &base_env(&active.base_path),
+            "/",
+        )?;
+        let ctx = PhaseContext::new(
+            source_dir_for(recipe),
+            prefix_for(recipe.kind()),
+            default_jobs(),
+        );
+        let pkg = PackageContext::new(dest);
+        self.invoke_with_runtime(
+            active,
+            &[PhaseArg::Ctx(ctx), PhaseArg::Pkg(pkg)],
+            recipe.phases().install(),
+        )?;
+        self.write_output_stamp(layout, recipe, output, "install")
+    }
+
+    fn task_install_host(
+        &self,
+        layout: &Layout<'_>,
+        recipe: &Recipe,
+        active: &ActiveContainer,
+    ) -> anyhow::Result<()> {
+        log::step("host-install", &recipe.key());
+        let dest = format!("/dest/{}", recipe.slug());
+        active.container.borrow().exec(
+            &["mkdir".to_owned(), "-p".to_owned(), dest.clone()],
+            &base_env(&active.base_path),
+            "/",
+        )?;
+        let ctx = PhaseContext::new(
+            source_dir_for(recipe),
+            prefix_for(recipe.kind()),
+            default_jobs(),
+        );
+        let pkg = PackageContext::new(dest.clone());
+        self.invoke_with_runtime(
+            active,
+            &[PhaseArg::Ctx(ctx), PhaseArg::Pkg(pkg)],
+            recipe.phases().install(),
+        )?;
+
+        let host_root = layout.host_install_root(recipe);
+        if host_root.exists() {
+            fs::remove_dir_all(&host_root)
+                .with_context(|| format!("clearing {}", host_root.display()))?;
+        }
+        fs::create_dir_all(&host_root)?;
+        active
+            .container
+            .borrow()
+            .cp_out(&format!("{dest}/."), &host_root)?;
+
+        self.write_recipe_stamp(layout, recipe, "host-install")
+    }
+
+    fn task_produce_apk(
+        &self,
+        layout: &Layout<'_>,
+        recipe: &Recipe,
+        output: &OutputPackage,
+        active: &ActiveContainer,
+    ) -> anyhow::Result<()> {
+        log::step("apk", &output.key());
+        let files_dir = format!("/dest/{}", output.name());
+        let file_name = format!(
+            "{}-{}-r{}.apk",
+            output.name(),
+            recipe.version(),
+            recipe.revision()
+        );
+        let out_in_container = format!("/pkgs/{file_name}");
+        let version = format!("{}-r{}", recipe.version(), recipe.revision());
+
+        let mut argv: Vec<String> = vec![
+            "apk".to_owned(),
+            "mkpkg".to_owned(),
+            "--files".to_owned(),
+            files_dir,
+            "--output".to_owned(),
+            out_in_container,
+            "--info".to_owned(),
+            format!("name:{}", output.name()),
+            "--info".to_owned(),
+            format!("version:{version}"),
+            "--info".to_owned(),
+            format!("arch:{}", self.config.arch),
+            "--info".to_owned(),
+            format!("origin:{}", recipe.key()),
+        ];
+        if let Some(desc) = output.metadata().description() {
+            argv.push("--info".to_owned());
+            argv.push(format!("description:{desc}"));
+        }
+        if let Some(license) = output.metadata().license() {
+            argv.push("--info".to_owned());
+            argv.push(format!("license:{license}"));
+        }
+        if let Some(url) = output.metadata().website() {
+            argv.push("--info".to_owned());
+            argv.push(format!("url:{url}"));
+        }
+        if let Some(packager) = output.metadata().maintainer() {
+            argv.push("--info".to_owned());
+            argv.push(format!("packager:{packager}"));
+        }
+        for dep in recipe.deps().iter().chain(recipe.run_deps().iter()) {
+            argv.push("--info".to_owned());
+            argv.push(format!("depends:{dep}"));
+        }
+
+        active
+            .container
+            .borrow()
+            .exec(&argv, &base_env(&active.base_path), "/")?;
+
+        self.write_output_stamp(layout, recipe, output, "apk")
+    }
+
+    fn invoke_with_runtime(
+        &self,
+        active: &ActiveContainer,
+        args: &[PhaseArg],
+        func: &OwnedFrozenValue,
+    ) -> anyhow::Result<()> {
+        let runtime = PhaseRuntime {
+            container: active.container.clone(),
+            base_path: active.base_path.clone(),
+            base_env: bare_env(),
+        };
+        let _guard = PhaseRuntimeGuard::enter(runtime);
+        phase::invoke_phase(func, args)
+    }
+
+    fn start_recipe_container(
+        &self,
+        recipes: &RecipeSet,
+        recipe_key: &str,
+    ) -> anyhow::Result<ActiveContainer> {
+        let recipe = recipes.recipe(recipe_key)?;
+        let layout = Layout::new(&self.root, &self.config.arch);
+
+        let source_dir = layout.source_workdir(recipe);
+        let build_dir = layout.build_workdir(recipe);
+        fs::create_dir_all(&source_dir)?;
+        fs::create_dir_all(&build_dir)?;
+
+        let host_deps = transitive_host_deps(recipes, recipe)?;
+        let pkgs_dir = self.root.join("build/pkgs").join(&self.config.arch);
+        fs::create_dir_all(&pkgs_dir)?;
+        let mut mounts = vec![
+            Mount {
+                host: source_dir,
+                container: "/sources".to_owned(),
+                read_only: false,
+            },
+            Mount {
+                host: build_dir,
+                container: "/build".to_owned(),
+                read_only: false,
+            },
+            Mount {
+                host: pkgs_dir,
+                container: "/pkgs".to_owned(),
+                read_only: false,
+            },
+        ];
+        let mut tools_bins: Vec<String> = Vec::new();
+        for dep_key in &host_deps {
+            let dep_recipe = recipes.recipe(dep_key)?;
+            let install = layout.host_install_dir(dep_recipe);
+            if !install.exists() {
+                bail!(
+                    "missing host install for {dep_key} at {}; build it first",
+                    install.display()
+                );
+            }
+            let bare = dep_key.strip_prefix("host:").unwrap_or(dep_key);
+            mounts.push(Mount {
+                host: install,
+                container: format!("/tools/{bare}/usr/local"),
+                read_only: true,
+            });
+            tools_bins.push(format!("/tools/{bare}/usr/local/bin"));
+        }
+
+        let name = format!(
+            "distro-builder-{}-{:x}",
+            std::process::id(),
+            random_suffix()
+        );
+        let container = Container::start(
+            &self.config.container_runtime,
+            &self.config.container_image,
+            &name,
+            &mounts,
+        )?;
+
+        let mut path_segments = tools_bins;
+        path_segments.push("/usr/local/sbin".to_owned());
+        path_segments.push("/usr/local/bin".to_owned());
+        path_segments.push("/usr/sbin".to_owned());
+        path_segments.push("/usr/bin".to_owned());
+        path_segments.push("/sbin".to_owned());
+        path_segments.push("/bin".to_owned());
+        let base_path = path_segments.join(":");
+
+        let active = ActiveContainer {
+            recipe_key: recipe_key.to_owned(),
+            container: Rc::new(RefCell::new(container)),
+            base_path,
+        };
+
+        Ok(active)
+    }
+
+    fn write_recipe_stamp(
+        &self,
+        layout: &Layout<'_>,
+        recipe: &Recipe,
+        kind: &str,
+    ) -> anyhow::Result<()> {
+        let path = layout.recipe_task_stamp(recipe, kind);
+        fs::create_dir_all(path.parent().unwrap())?;
+        fs::write(path, layout.recipe_fingerprint(recipe)?)?;
+        Ok(())
+    }
+
+    fn write_output_stamp(
+        &self,
+        layout: &Layout<'_>,
+        recipe: &Recipe,
+        output: &OutputPackage,
+        kind: &str,
+    ) -> anyhow::Result<()> {
+        let path = layout.output_task_stamp(output, kind);
+        fs::create_dir_all(path.parent().unwrap())?;
+        fs::write(path, layout.output_fingerprint(recipe, output)?)?;
+        Ok(())
+    }
+
+    fn ensure_container_image(&self, dockerfile: &Path) -> anyhow::Result<()> {
+        if !dockerfile.exists() {
+            bail!(
+                "configured container Dockerfile does not exist: {}",
+                dockerfile.display()
+            );
+        }
+
+        let hash = self.container_build_hash(dockerfile)?;
+        let stamp = self.root.join("build/container-image.hash");
+        if fs::read_to_string(&stamp).ok().as_deref() == Some(hash.as_str())
+            && self.container_image_exists()?
+        {
+            log::skip(
+                "image",
+                &format!("using cached {}", self.config.container_image),
+            );
+            return Ok(());
+        }
+
+        log::step(
+            "image",
+            &format!(
+                "building {} from {}",
+                self.config.container_image,
+                dockerfile.display()
+            ),
+        );
+        let runtime = self.config.container_runtime.as_str();
+        let status = Command::new(runtime)
+            .arg("build")
+            .arg("-f")
+            .arg(dockerfile)
+            .arg("-t")
+            .arg(&self.config.container_image)
+            .arg(&self.root)
+            .status()
+            .with_context(|| {
+                format!(
+                    "failed to build container image `{}` from {}",
+                    self.config.container_image,
+                    dockerfile.display()
+                )
+            })?;
+        if !status.success() {
+            bail!(
+                "container image build failed for `{}` with {status}",
+                self.config.container_image
+            );
+        }
+
+        fs::create_dir_all(stamp.parent().unwrap())?;
+        fs::write(stamp, hash)?;
+        Ok(())
+    }
+
+    fn container_image_exists(&self) -> anyhow::Result<bool> {
+        let runtime = self.config.container_runtime.as_str();
+        let status = Command::new(runtime)
+            .arg("image")
+            .arg("exists")
+            .arg(&self.config.container_image)
+            .stdout(Stdio::null())
+            .stderr(Stdio::null())
+            .status()
+            .with_context(|| {
+                format!(
+                    "failed to inspect container image `{}`",
+                    self.config.container_image
+                )
+            })?;
+        Ok(status.success())
+    }
+
+    fn container_build_hash(&self, dockerfile: &Path) -> anyhow::Result<String> {
+        let mut hasher = Sha256::new();
+        hasher.update(fs::read(dockerfile)?);
+        hasher.update(self.config.container_image.as_bytes());
+        Ok(hex::encode(hasher.finalize()))
+    }
+
+    fn print_plan(&self, plan: &TaskPlan) {
+        if plan.is_empty() {
+            log::skip("plan", "nothing to do");
+            return;
+        }
+
+        log::step(
+            "plan",
+            &format!(
+                "{} active task(s), {} edge(s)",
+                plan.order().len(),
+                plan.dependency_count()
+            ),
+        );
+        for task in plan.order() {
+            println!("{task}");
+        }
+    }
+
+    fn abs_config_path(&self, path: &Path) -> PathBuf {
+        if path.is_absolute() {
+            path.to_path_buf()
+        } else {
+            self.root.join(path)
+        }
+    }
+}
+
+struct ActiveContainer {
+    recipe_key: String,
+    container: Rc<RefCell<Container>>,
+    base_path: String,
+}
+
+fn task_needs_container(task: &TaskId) -> bool {
+    matches!(
+        task,
+        TaskId::ConfigureRecipe(_)
+            | TaskId::BuildRecipe(_)
+            | TaskId::InstallPackageFiles(_)
+            | TaskId::ProduceApk(_)
+            | TaskId::InstallHostRecipe(_)
+    )
+}
+
+fn prefix_for(kind: RecipeKind) -> &'static str {
+    match kind {
+        RecipeKind::Package => "/usr",
+        RecipeKind::HostPackage => "/usr/local",
+    }
+}
+
+fn source_dir_for(recipe: &Recipe) -> SourceDir {
+    let entries = recipe.sources().entries();
+    let named: Vec<(&str, &crate::recipe::Source)> = entries
+        .iter()
+        .filter_map(|(name, src)| name.map(|n| (n, *src)))
+        .collect();
+    if named.is_empty() {
+        SourceDir::single("/sources")
+    } else {
+        SourceDir::named(
+            named
+                .into_iter()
+                .map(|(n, _)| (n.to_owned(), format!("/sources/{n}"))),
+        )
+    }
+}
+
+fn default_jobs() -> i32 {
+    thread::available_parallelism()
+        .map(|n| n.get() as i32)
+        .unwrap_or(1)
+}
+
+fn bare_env() -> Vec<(String, String)> {
+    vec![
+        ("PATH".to_owned(), String::new()),
+        ("HOME".to_owned(), "/tmp".to_owned()),
+        ("TERM".to_owned(), "dumb".to_owned()),
+        ("LC_ALL".to_owned(), "C".to_owned()),
+    ]
+}
+
+fn base_env(path: &str) -> Vec<(String, String)> {
+    let mut env = bare_env();
+    if let Some(slot) = env.iter_mut().find(|(k, _)| k == "PATH") {
+        slot.1 = path.to_owned();
+    }
+    env
+}
+
+fn transitive_host_deps(recipes: &RecipeSet, recipe: &Recipe) -> anyhow::Result<Vec<String>> {
+    let mut order: Vec<String> = Vec::new();
+    let mut seen: BTreeSet<String> = BTreeSet::new();
+    let mut queue: VecDeque<String> = recipe
+        .host_deps()
+        .iter()
+        .map(|d| RecipeKind::HostPackage.key(d))
+        .collect();
+    while let Some(key) = queue.pop_front() {
+        if !seen.insert(key.clone()) {
+            continue;
+        }
+        let dep = recipes.recipe(&key)?;
+        for sub in dep.host_deps() {
+            queue.push_back(RecipeKind::HostPackage.key(sub));
+        }
+        order.push(key);
+    }
+    Ok(order)
+}
+
+fn random_suffix() -> u64 {
+    let nanos = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|d| d.subsec_nanos() as u64)
+        .unwrap_or(0);
+    nanos.wrapping_mul(0x9E3779B97F4A7C15)
+}

src/cli.rs

@@ -1,27 +1,13 @@
-use crate::{
-    container::{ContainerManager, PodmanRuntime},
-    eval::{
-        Config, ContainerConfig, ContainerManagerWrapper, Context, Path, config_globals,
-        eval_files, types_globals,
-    },
-    log,
-    plan::{Plan, PlanKey},
-    recipe::RecipeSet,
-};
-
 use clap::{Parser, Subcommand};
-use starlark::{
-    environment::{GlobalsBuilder, Module},
-    eval,
-    values::Value,
-};
-use std::{cell::Cell, path::PathBuf, sync::Arc};
+use std::path::PathBuf;
+
+use crate::{builder::Builder, config::Config, eval, recipe::RecipeSet};
 
 #[derive(Debug, Parser)]
 struct Cli {
     #[arg(
         long,
-        short = 'C',
+        short,
         default_value = ".",
         help = "Directory containing the configuration and recipe files"
     )]
@@ -60,78 +46,32 @@ struct BuildCommand {
 enum Command {
     Fetch(FetchCommand),
     Build(BuildCommand),
+    #[command(about = "Create or refresh the configured build container image")]
+    Image,
 }
 
 pub fn run() -> anyhow::Result<()> {
     let cli = Cli::parse();
+
     let root_path = cli.root.canonicalize().unwrap_or(cli.root);
-
-    let config: Config = {
-        let cell = Cell::new(None);
-        let config_path = root_path.join("config.star");
-
-        eval_files(
-            &[&config_path],
-            &GlobalsBuilder::standard()
-                .with(types_globals)
-                .with(config_globals)
-                .build(),
-            None,
-            None,
-            Some(&cell),
-        )?;
-
-        cell.take()
-            .ok_or_else(|| anyhow::anyhow!("`config` was not called"))?
-    };
-
-    let container_runtime = match config.container() {
-        ContainerConfig::Podman(_) => Arc::new(PodmanRuntime::new()?),
-    };
-
-    let container_manager = ContainerManager::new(container_runtime);
-    let mut recipes = RecipeSet::new(&config);
-
-    recipes.load_recipes(
-        &root_path.join(config.recipes_dir()),
-        &root_path.join(config.host_recipes_dir()),
-    )?;
-
-    // let wrapper = ContainerManagerWrapper(&container_manager);
-    // for (name, recipe) in recipes.packages.iter() {
-    //     println!("{name}: {:#?}", recipe);
-
-    //     let mo = Module::new();
-    //     let mut eval = eval::Evaluator::new(&mo);
-    //     eval.extra = Some(&wrapper);
-    //     eval.eval_function(
-    //         recipe.build.unwrap().0.to_value(),
-    //         &[mo.heap().alloc(Context {
-    //             source_dir: Path::new("/source"),
-    //             build_dir: Path::new("/build"),
-    //             jobs: 4,
-    //         })],
-    //         &[],
-    //     )
-    //     .unwrap();
-    // }
-
-    let mut plan = Plan::new(&recipes);
+    let config = Config::load(&root_path.join("config.star"))?;
 
     match cli.command {
-        Command::Fetch(_) => {}
-        Command::Build(cmd) => {
-            for recipe in cmd.recipes.iter() {
-                plan.add_wanted(if let Some(recipe) = recipe.strip_prefix("host:") {
-                    PlanKey::ToolInstall(recipe.to_string())
-                } else {
-                    PlanKey::PkgPackage(recipe.clone())
-                });
-            }
+        Command::Fetch(command) => {
+            let lib = eval::eval_lib(&root_path.join("lib"), Some(&config.options))?;
+            let recipes = RecipeSet::load(&root_path, &config.options, lib.as_ref())?;
+            let mut builder = Builder::new(root_path, config);
+            builder.fetch(&recipes, &command.recipes, command.dry_run)
+        }
+        Command::Build(command) => {
+            let lib = eval::eval_lib(&root_path.join("lib"), Some(&config.options))?;
+            let recipes = RecipeSet::load(&root_path, &config.options, lib.as_ref())?;
+            let mut builder = Builder::new(root_path, config);
+            builder.build(&recipes, &command.recipes, command.rebuild, command.dry_run)
+        }
+        Command::Image => {
+            let mut builder = Builder::new(root_path, config);
+            builder.ensure_container_ready()
         }
     }
-
-    log!("plan", "{:#?}", plan.steps());
-
-    Ok(())
 }

src/config.rs

@@ -0,0 +1,117 @@
+use std::{
+    collections::HashMap,
+    path::{Path, PathBuf},
+};
+
+use starlark::values::dict::FrozenDictRef;
+
+use crate::{
+    eval::{ExtractError, eval_file, extract_string},
+    options::Options,
+};
+
+#[derive(Debug)]
+pub enum ContainerRuntime {
+    Docker,
+    Podman,
+}
+
+impl ContainerRuntime {
+    pub fn as_str(&self) -> &'static str {
+        match self {
+            Self::Docker => "docker",
+            Self::Podman => "podman",
+        }
+    }
+}
+
+impl std::fmt::Display for ContainerRuntime {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(self.as_str())
+    }
+}
+
+impl TryFrom<&str> for ContainerRuntime {
+    type Error = anyhow::Error;
+
+    fn try_from(value: &str) -> anyhow::Result<Self> {
+        match value {
+            "docker" => Ok(Self::Docker),
+            "podman" => Ok(Self::Podman),
+            _ => anyhow::bail!("invalid runtime: {value}"),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct Config {
+    pub container_runtime: ContainerRuntime,
+    pub container_image: String,
+    pub container_dockerfile: PathBuf,
+
+    pub arch: String,
+    pub options: Options,
+}
+
+impl Config {
+    pub fn load(path: &Path) -> anyhow::Result<Self> {
+        let module = eval_file(path, None, None)?;
+
+        let container_runtime = match extract_string(&module, "container_runtime") {
+            Ok(v) => ContainerRuntime::try_from(v.as_str())?,
+            Err(ExtractError::NotFound) => ContainerRuntime::Podman,
+            Err(ExtractError::TypeMismatch) => anyhow::bail!("`container_runtime` is not a string"),
+        };
+        let container_image = match extract_string(&module, "container_image") {
+            Ok(container_image) => container_image,
+            Err(ExtractError::NotFound) => {
+                anyhow::bail!("`container_image` config variable not set")
+            }
+            Err(ExtractError::TypeMismatch) => anyhow::bail!("`container_image` is not a string"),
+        };
+        let container_dockerfile = match extract_string(&module, "container_dockerfile") {
+            Ok(container_dockerfile) => PathBuf::from(container_dockerfile),
+            Err(ExtractError::NotFound) => PathBuf::from("Dockerfile"),
+            Err(ExtractError::TypeMismatch) => {
+                anyhow::bail!("`container_dockerfile` is not a string")
+            }
+        };
+        let arch = match extract_string(&module, "arch") {
+            Ok(arch) => arch,
+            Err(ExtractError::NotFound) => anyhow::bail!("`arch` config variable not set"),
+            Err(ExtractError::TypeMismatch) => anyhow::bail!("`arch` is not a string"),
+        };
+
+        let frozen_module = module.freeze()?;
+        let options_value = frozen_module
+            .get_option("options")?
+            .ok_or_else(|| anyhow::anyhow!("`options` config variable not set"))?;
+        let entries = {
+            // SAFETY: the FrozenValue is only used to construct a FrozenDictRef whose
+            // lifetime is bounded by `options_value`, which keeps the frozen heap alive.
+            let dict =
+                FrozenDictRef::from_frozen_value(unsafe { options_value.unchecked_frozen_value() })
+                    .ok_or_else(|| anyhow::anyhow!("`options` is not a dict"))?;
+            dict.iter()
+                .map(|(k, v)| {
+                    let key = k
+                        .to_value()
+                        .unpack_str()
+                        .ok_or_else(|| anyhow::anyhow!("non-string key in `options`"))?
+                        .to_owned();
+                    Ok((key, options_value.map(|_| v)))
+                })
+                .collect::<anyhow::Result<HashMap<_, _>>>()?
+        };
+        let options = Options::new(entries);
+
+        Ok(Self {
+            container_runtime,
+            container_image,
+            container_dockerfile,
+
+            arch,
+            options,
+        })
+    }
+}

src/container.rs

@@ -0,0 +1,163 @@
+use std::{
+    path::{Path, PathBuf},
+    process::{Command, Stdio},
+};
+
+use anyhow::{Context, bail};
+
+use crate::config::ContainerRuntime;
+
+#[derive(Debug, Clone)]
+pub struct Mount {
+    pub host: PathBuf,
+    pub container: String,
+    pub read_only: bool,
+}
+
+#[derive(Debug)]
+pub struct Container {
+    runtime: &'static str,
+    id: String,
+    stopped: bool,
+}
+
+impl Container {
+    pub fn start(
+        runtime: &ContainerRuntime,
+        image: &str,
+        name: &str,
+        mounts: &[Mount],
+    ) -> anyhow::Result<Self> {
+        let runtime_str = runtime.as_str();
+        let mut cmd = Command::new(runtime_str);
+        cmd.arg("run")
+            .arg("-d")
+            .arg("--rm")
+            .arg("--name")
+            .arg(name)
+            .arg("--read-only")
+            .arg("--tmpfs")
+            .arg("/tmp")
+            .arg("--tmpfs")
+            .arg("/dest")
+            .arg("--tmpfs")
+            .arg("/sysroot")
+            .arg("--network=none");
+
+        if matches!(runtime, ContainerRuntime::Podman) {
+            cmd.arg("--userns=keep-id");
+        }
+
+        for mount in mounts {
+            let mut spec = format!("{}:{}", mount.host.display(), mount.container);
+            if mount.read_only {
+                spec.push_str(":ro");
+            }
+            cmd.arg("-v").arg(spec);
+        }
+
+        cmd.arg(image).arg("sleep").arg("infinity");
+        cmd.stdout(Stdio::piped()).stderr(Stdio::inherit());
+
+        let output = cmd
+            .output()
+            .with_context(|| format!("spawning `{runtime_str} run` for image `{image}`"))?;
+        if !output.status.success() {
+            bail!(
+                "`{runtime_str} run` failed with {} for image `{image}`",
+                output.status
+            );
+        }
+
+        let id = String::from_utf8(output.stdout)
+            .context("container id is not valid UTF-8")?
+            .trim()
+            .to_owned();
+        if id.is_empty() {
+            bail!("`{runtime_str} run` returned an empty container id");
+        }
+
+        Ok(Self {
+            runtime: runtime_str,
+            id,
+            stopped: false,
+        })
+    }
+
+    pub fn exec(&self, argv: &[String], env: &[(String, String)], cwd: &str) -> anyhow::Result<()> {
+        if argv.is_empty() {
+            bail!("ctx.run called with an empty argv");
+        }
+
+        let mut cmd = Command::new(self.runtime);
+        cmd.arg("exec").arg("-w").arg(cwd);
+        for (k, v) in env {
+            cmd.arg("-e").arg(format!("{k}={v}"));
+        }
+        cmd.arg(&self.id);
+        cmd.args(argv);
+
+        let status = cmd.status().with_context(|| {
+            format!("spawning `{} exec` in container {}", self.runtime, self.id)
+        })?;
+        if !status.success() {
+            bail!("command {argv:?} failed with {status}");
+        }
+        Ok(())
+    }
+
+    pub fn cp_out(&self, src_in_container: &str, host_dst: &Path) -> anyhow::Result<()> {
+        let spec = format!("{}:{}", self.id, src_in_container);
+        let status = Command::new(self.runtime)
+            .arg("cp")
+            .arg(spec)
+            .arg(host_dst)
+            .status()
+            .with_context(|| format!("spawning `{} cp`", self.runtime))?;
+        if !status.success() {
+            bail!(
+                "`{} cp` failed with {status} for {src_in_container} -> {}",
+                self.runtime,
+                host_dst.display()
+            );
+        }
+        Ok(())
+    }
+
+    pub fn stop(mut self) -> anyhow::Result<()> {
+        self.stop_inner()
+    }
+
+    fn stop_inner(&mut self) -> anyhow::Result<()> {
+        if self.stopped {
+            return Ok(());
+        }
+        self.stopped = true;
+        let status = Command::new(self.runtime)
+            .arg("rm")
+            .arg("-f")
+            .arg(&self.id)
+            .stdout(Stdio::null())
+            .stderr(Stdio::null())
+            .status()
+            .with_context(|| format!("spawning `{} rm`", self.runtime))?;
+        if !status.success() {
+            bail!("`{} rm -f {}` failed with {status}", self.runtime, self.id);
+        }
+        Ok(())
+    }
+}
+
+impl Drop for Container {
+    fn drop(&mut self) {
+        if !self.stopped {
+            let _ = Command::new(self.runtime)
+                .arg("rm")
+                .arg("-f")
+                .arg(&self.id)
+                .stdout(Stdio::null())
+                .stderr(Stdio::null())
+                .status();
+        }
+    }
+}

src/container/mod.rs

@@ -1,99 +0,0 @@
-use std::{
-    collections::HashMap,
-    path::Path,
-    sync::{Arc, Mutex},
-};
-
-mod podman;
-
-pub use podman::PodmanRuntime;
-
-#[derive(Clone)]
-pub struct Container {
-    id: String,
-    runtime: Arc<dyn ContainerRuntime>,
-}
-
-impl Container {
-    fn new(id: String, runtime: Arc<dyn ContainerRuntime>) -> Self {
-        Self { id, runtime }
-    }
-
-    pub fn id(&self) -> &str {
-        &self.id
-    }
-
-    pub fn exec<'a, 'e, 'c>(
-        &self,
-        argv: impl Into<Vec<&'a str>>,
-        env: impl Into<Vec<(&'e str, &'e str)>>,
-        cwd: impl Into<&'c Path>,
-    ) -> anyhow::Result<()> {
-        self.runtime
-            .exec(self.id(), argv.into(), env.into(), cwd.into())
-    }
-}
-
-pub trait ContainerRuntime {
-    /// Starts a new container, returns the ID.
-    fn start_container(
-        &self,
-        image_name: &str,
-        mounts: &[(&Path, &str, bool)],
-    ) -> anyhow::Result<String>;
-
-    /// Stops a container.
-    fn stop_container(&self, container_id: &str);
-
-    /// Executes a command in a container.
-    fn exec(
-        &self,
-        container_id: &str,
-        argv: Vec<&str>,
-        env: Vec<(&str, &str)>,
-        cwd: &Path,
-    ) -> anyhow::Result<()>;
-}
-
-pub struct ContainerManager {
-    inner: Mutex<ContainerManagerInner>,
-}
-
-struct ContainerManagerInner {
-    containers: HashMap<String, Container>,
-    runtime: Arc<dyn ContainerRuntime>,
-}
-
-impl ContainerManager {
-    pub fn new(runtime: Arc<dyn ContainerRuntime>) -> Self {
-        Self {
-            inner: Mutex::new(ContainerManagerInner {
-                containers: HashMap::new(),
-                runtime,
-            }),
-        }
-    }
-
-    pub fn container(&self, name: &str) -> anyhow::Result<Container> {
-        let mut inner = self.inner.lock().unwrap();
-        if inner.containers.get(name).is_none() {
-            let container_id = inner.runtime.start_container("alpine:edge", &[])?;
-
-            crate::log!("info", "Started new container ({container_id})");
-
-            let container = Container::new(container_id, inner.runtime.clone());
-            inner.containers.insert(name.into(), container);
-        }
-
-        Ok(inner.containers.get(name).cloned().unwrap())
-    }
-}
-
-impl Drop for ContainerManager {
-    fn drop(&mut self) {
-        let inner = self.inner.lock().unwrap();
-        for (_, container) in inner.containers.iter() {
-            inner.runtime.stop_container(container.id());
-        }
-    }
-}

src/container/podman.rs

@@ -1,101 +0,0 @@
-use crate::container::ContainerRuntime;
-
-use anyhow::Context;
-use std::{
-    path::Path,
-    process::{Command, Stdio},
-};
-
-pub struct PodmanRuntime;
-
-impl PodmanRuntime {
-    pub fn new() -> anyhow::Result<Self> {
-        let output = Command::new("podman").arg("--version").output()?;
-
-        if output.status.success() {
-            Ok(Self)
-        } else {
-            anyhow::bail!(
-                "Could not execute `podman --version` - make sure you have podman installed."
-            );
-        }
-    }
-}
-
-impl ContainerRuntime for PodmanRuntime {
-    fn start_container(
-        &self,
-        image_name: &str,
-        mounts: &[(&Path, &str, bool)],
-    ) -> anyhow::Result<String> {
-        let mut cmd = Command::new("podman");
-
-        cmd.arg("run");
-        cmd.arg("--detach");
-        cmd.arg("--read-only");
-        cmd.arg("--network=none");
-        cmd.arg("--userns=keep-id");
-        cmd.arg("--tmpfs").arg("/builder/dest");
-        cmd.arg("--tmpfs").arg("/builder/sysroot");
-
-        for &(host, container, read_only) in mounts {
-            cmd.arg("--volume").arg(format!(
-                "{}:{}{}",
-                host.display(),
-                container,
-                if read_only { ":ro" } else { "" }
-            ));
-        }
-
-        cmd.arg(image_name);
-        cmd.arg("sleep").arg("infinity");
-
-        let output = cmd.output()?;
-
-        if output.status.success() {
-            Ok(String::from_utf8(output.stdout)
-                .context("container ID is not valid UTF-8")?
-                .trim()
-                .into())
-        } else {
-            todo!()
-        }
-    }
-
-    fn stop_container(&self, container_id: &str) {
-        Command::new("podman")
-            .arg("kill")
-            .arg(container_id)
-            .output()
-            .unwrap();
-    }
-
-    fn exec(
-        &self,
-        container_id: &str,
-        argv: Vec<&str>,
-        env: Vec<(&str, &str)>,
-        cwd: &Path,
-    ) -> anyhow::Result<()> {
-        let mut cmd = Command::new("podman");
-
-        cmd.arg("exec");
-        cmd.arg("--workdir").arg(cwd);
-
-        for (key, value) in env {
-            cmd.arg("--env").arg(format!("{key}={value}"));
-        }
-
-        cmd.arg(container_id);
-        cmd.args(argv);
-        cmd.stdout(Stdio::inherit()).stderr(Stdio::inherit());
-
-        let output = cmd.output()?;
-
-        if output.status.success() {
-            Ok(())
-        } else {
-            anyhow::bail!("Failed to execute command");
-        }
-    }
-}

src/eval.rs

@@ -0,0 +1,177 @@
+use anyhow::Context;
+use starlark::{
+    environment::{FrozenModule, Globals, GlobalsBuilder, Module},
+    eval::Evaluator,
+    syntax::{AstModule, Dialect},
+    values::list::ListRef,
+};
+use std::path::{Path, PathBuf};
+use walkdir::WalkDir;
+
+use crate::{
+    options::Options,
+    recipe::{GitSource, Metadata, Source, Subpackage, TarballSource},
+};
+
+#[derive(Debug)]
+pub enum ExtractError {
+    NotFound,
+    TypeMismatch,
+}
+
+impl std::fmt::Display for ExtractError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            ExtractError::NotFound => write!(f, "missing"),
+            ExtractError::TypeMismatch => write!(f, "wrong type"),
+        }
+    }
+}
+
+impl std::error::Error for ExtractError {}
+
+#[starlark::starlark_module]
+fn builder_globals(builder: &mut GlobalsBuilder) {
+    fn meta(
+        maintainer: Option<String>,
+        description: Option<String>,
+        license: Option<String>,
+        website: Option<String>,
+    ) -> anyhow::Result<Metadata> {
+        Ok(Metadata::new(maintainer, description, license, website))
+    }
+
+    fn tarball_source(
+        url: String,
+        sha256: String,
+        strip_components: Option<u32>,
+    ) -> anyhow::Result<Source> {
+        Ok(Source::Tarball(TarballSource::new(
+            url,
+            sha256,
+            strip_components.unwrap_or(0),
+        )))
+    }
+
+    fn git_source(url: String, commit: String) -> anyhow::Result<Source> {
+        Ok(Source::Git(GitSource::new(url, commit)))
+    }
+
+    fn subpackage(name: String, metadata: Option<&Metadata>) -> anyhow::Result<Subpackage> {
+        let metadata = metadata
+            .cloned()
+            .unwrap_or_else(|| Metadata::new(None, None, None, None));
+        Ok(Subpackage::new(name, metadata))
+    }
+}
+
+pub fn eval_file(
+    path: &Path,
+    options: Option<&Options>,
+    lib: Option<&FrozenModule>,
+) -> anyhow::Result<Module> {
+    let module = Module::new();
+    if let Some(lib) = lib {
+        module.import_public_symbols(lib);
+    }
+    if let Some(options) = options {
+        inject_options(&module, options);
+    }
+
+    let ast = AstModule::parse_file(path, &dialect()).map_err(|err| anyhow::anyhow!("{err}"))?;
+    let globals = globals();
+
+    let mut eval = Evaluator::new(&module);
+    eval.eval_module(ast, &globals)
+        .map_err(|err| anyhow::anyhow!("{err}"))?;
+    drop(eval);
+
+    Ok(module)
+}
+
+/// Parse and evaluate every `.star` file under `dir` into a single frozen
+/// module whose public bindings can be imported into recipe modules. Returns
+/// `Ok(None)` if `dir` doesn't exist or contains no `.star` files.
+pub fn eval_lib(dir: &Path, options: Option<&Options>) -> anyhow::Result<Option<FrozenModule>> {
+    if !dir.exists() {
+        return Ok(None);
+    }
+
+    let mut files: Vec<PathBuf> = Vec::new();
+    for entry in WalkDir::new(dir) {
+        let entry = entry.with_context(|| format!("walking lib directory {}", dir.display()))?;
+        let path = entry.path();
+        if entry.file_type().is_file() && path.extension().is_some_and(|ext| ext == "star") {
+            files.push(path.to_path_buf());
+        }
+    }
+    if files.is_empty() {
+        return Ok(None);
+    }
+    // Sorted for deterministic ordering when later definitions shadow earlier ones.
+    files.sort();
+
+    let module = Module::new();
+    if let Some(options) = options {
+        inject_options(&module, options);
+    }
+    let dialect = dialect();
+    let globals = globals();
+
+    for file in &files {
+        let ast = AstModule::parse_file(file, &dialect)
+            .map_err(|err| anyhow::anyhow!("parsing {}: {err}", file.display()))?;
+        let mut eval = Evaluator::new(&module);
+        eval.eval_module(ast, &globals)
+            .map_err(|err| anyhow::anyhow!("evaluating {}: {err}", file.display()))?;
+    }
+
+    Ok(Some(module.freeze()?))
+}
+
+fn dialect() -> Dialect {
+    Dialect {
+        enable_top_level_stmt: true,
+        enable_f_strings: true,
+        ..Dialect::Standard
+    }
+}
+
+fn globals() -> Globals {
+    GlobalsBuilder::standard().with(builder_globals).build()
+}
+
+fn inject_options(module: &Module, options: &Options) {
+    let value = module.heap().alloc(options.clone());
+    module.set("options", value);
+}
+
+pub fn extract_string(module: &Module, key: &str) -> Result<String, ExtractError> {
+    module
+        .get(key)
+        .ok_or_else(|| ExtractError::NotFound)
+        .and_then(|v| {
+            v.unpack_str()
+                .map(|v| v.to_string())
+                .ok_or_else(|| ExtractError::TypeMismatch)
+        })
+}
+
+pub fn extract_i32(module: &Module, key: &str) -> Result<i32, ExtractError> {
+    module
+        .get(key)
+        .ok_or(ExtractError::NotFound)
+        .and_then(|v| v.unpack_i32().ok_or(ExtractError::TypeMismatch))
+}
+
+pub fn extract_string_list(module: &Module, key: &str) -> Result<Vec<String>, ExtractError> {
+    let value = module.get(key).ok_or(ExtractError::NotFound)?;
+    let list = ListRef::from_value(value).ok_or(ExtractError::TypeMismatch)?;
+    list.iter()
+        .map(|v| {
+            v.unpack_str()
+                .map(|s| s.to_string())
+                .ok_or(ExtractError::TypeMismatch)
+        })
+        .collect()
+}

src/eval/config.rs

@@ -1,154 +0,0 @@
-use crate::eval::Path;
-
-use allocative::Allocative;
-use starlark::{
-    collections::SmallMap,
-    environment::GlobalsBuilder,
-    eval::Evaluator,
-    starlark_module, starlark_simple_value,
-    values::{StarlarkValue, Value, ValueLike, none::NoneType},
-};
-use starlark_derive::{NoSerialize, ProvidesStaticType, starlark_value};
-use std::{
-    cell::Cell,
-    collections::HashMap,
-    path::{Path as StdPath, PathBuf},
-};
-
-#[derive(Debug, Clone, Allocative, NoSerialize, ProvidesStaticType)]
-pub struct PodmanConfig {
-    image: String,
-    dockerfile: PathBuf,
-}
-
-impl std::fmt::Display for PodmanConfig {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "podman_config")
-    }
-}
-
-starlark_simple_value!(PodmanConfig);
-
-#[starlark_value(type = "podman_config")]
-impl<'v> StarlarkValue<'v> for PodmanConfig {}
-
-#[derive(Debug, Clone, Allocative, NoSerialize, ProvidesStaticType)]
-pub enum ContainerConfig {
-    Podman(PodmanConfig),
-}
-
-impl std::fmt::Display for ContainerConfig {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "container_config")
-    }
-}
-
-starlark_simple_value!(ContainerConfig);
-
-#[starlark_value(type = "container_config")]
-impl<'v> StarlarkValue<'v> for ContainerConfig {}
-
-#[derive(Debug, Clone, Allocative, ProvidesStaticType)]
-pub enum ConfigValue {
-    String(String),
-    Integer(i32),
-    Bool(bool),
-    Path(Path),
-}
-
-#[derive(Debug, Clone, Allocative, NoSerialize, ProvidesStaticType)]
-pub struct Config {
-    arch: String,
-    container: ContainerConfig,
-    recipes_dir: Path,
-    host_recipes_dir: Path,
-
-    options: HashMap<String, ConfigValue>,
-}
-
-impl Config {
-    pub fn arch(&self) -> &str {
-        &self.arch
-    }
-
-    pub fn container(&self) -> &ContainerConfig {
-        &self.container
-    }
-
-    pub fn recipes_dir(&self) -> &StdPath {
-        &self.recipes_dir.path()
-    }
-
-    pub fn host_recipes_dir(&self) -> &StdPath {
-        &self.host_recipes_dir.path()
-    }
-
-    pub fn options(&self) -> &HashMap<String, ConfigValue> {
-        &self.options
-    }
-}
-
-impl std::fmt::Display for Config {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "container_config")
-    }
-}
-
-starlark_simple_value!(Config);
-
-#[starlark_value(type = "config")]
-impl<'v> StarlarkValue<'v> for Config {}
-
-#[starlark_module]
-pub fn config_globals(b: &mut GlobalsBuilder) {
-    fn podman(
-        #[starlark(require = named)] image: &str,
-        #[starlark(require = named)] dockerfile: &Path,
-    ) -> anyhow::Result<ContainerConfig> {
-        Ok(ContainerConfig::Podman(PodmanConfig {
-            image: image.to_string(),
-            dockerfile: dockerfile.path().to_owned(),
-        }))
-    }
-
-    fn config(
-        #[starlark(require = named)] arch: &str,
-        #[starlark(require = named)] container: &ContainerConfig,
-        #[starlark(require = named)] recipes_dir: &Path,
-        #[starlark(require = named)] host_recipes_dir: &Path,
-        #[starlark(kwargs)] kwargs: SmallMap<&str, Value>,
-        eval: &mut Evaluator,
-    ) -> anyhow::Result<NoneType> {
-        let config = eval
-            .extra
-            .and_then(|extra| extra.downcast_ref::<Cell<Option<Config>>>())
-            .ok_or_else(|| anyhow::anyhow!("`config` called outside of config.star"))?;
-
-        config.set(Some(Config {
-            arch: arch.to_string(),
-            container: container.clone(),
-            recipes_dir: recipes_dir.clone(),
-            host_recipes_dir: host_recipes_dir.clone(),
-            options: kwargs
-                .iter()
-                .map(|(&k, v)| {
-                    let value = if let Some(str) = v.unpack_str() {
-                        ConfigValue::String(str.to_string())
-                    } else if let Some(num) = v.unpack_i32() {
-                        ConfigValue::Integer(num)
-                    } else if let Some(bool) = v.unpack_bool() {
-                        ConfigValue::Bool(bool)
-                    } else if let Some(path) = v.downcast_ref::<Path>() {
-                        ConfigValue::Path(path.clone())
-                    } else {
-                        anyhow::bail!("config option must be a `string`, `int`, `bool` or `path`");
-                    };
-
-                    Ok((k.to_string(), value))
-                })
-                .collect::<Result<_, _>>()?,
-        }));
-
-        Ok(NoneType)
-    }
-}

src/eval/mod.rs

@@ -1,96 +0,0 @@
-use starlark::{
-    any::AnyLifetime,
-    environment::{FrozenModule, Globals, Module},
-    eval::Evaluator,
-    syntax::{AstModule, Dialect, DialectTypes},
-    values::{UnpackValue, Value, type_repr::StarlarkTypeRepr},
-};
-use std::path::Path as StdPath;
-
-mod config;
-mod recipe;
-mod types;
-
-#[allow(unused_imports)]
-pub use config::*;
-#[allow(unused_imports)]
-pub use recipe::*;
-#[allow(unused_imports)]
-pub use types::*;
-
-pub trait UnpackCloned: Sized + StarlarkTypeRepr {
-    fn unpack_cloned(value: Value<'_>) -> Option<Self>;
-}
-
-impl<T> UnpackCloned for T
-where
-    for<'v> T: UnpackValue<'v>,
-{
-    fn unpack_cloned(value: Value<'_>) -> Option<Self> {
-        T::unpack_value(value).unwrap()
-    }
-}
-
-pub fn eval_files(
-    path: &[&StdPath],
-    globals: &Globals,
-    lib_module: Option<&FrozenModule>,
-    config: Option<&Config>,
-    extra: Option<&dyn AnyLifetime>,
-) -> anyhow::Result<Module> {
-    use anyhow::Context;
-
-    let module = Module::new();
-
-    if let Some(lib_module) = lib_module {
-        module.import_public_symbols(lib_module);
-    }
-
-    if let Some(config) = config {
-        module.set("options", module.heap().alloc(config.clone()));
-    }
-
-    let mut paths = path.to_vec();
-
-    paths.sort();
-
-    let ast_modules = paths
-        .iter()
-        .map(|&path| {
-            let module = AstModule::parse_file(path, &default_dialect())
-                .map_err(|err| anyhow::anyhow!("{err}"))
-                .context(format!("parsing file {:?}", path.display()))?;
-
-            Ok((path, module))
-        })
-        .collect::<anyhow::Result<Vec<(&StdPath, AstModule)>>>()?;
-
-    for (path, ast) in ast_modules {
-        let mut eval = Evaluator::new(&module);
-
-        if let Some(extra) = extra {
-            eval.extra = Some(extra);
-        }
-
-        eval.eval_module(ast, globals)
-            .map_err(|err| anyhow::anyhow!("{err}"))
-            .context(format!("evaluating file {:?}", path.display()))?;
-    }
-
-    Ok(module)
-}
-
-fn default_dialect() -> Dialect {
-    Dialect {
-        enable_def: true,
-        enable_lambda: true,
-        enable_load: false,
-        enable_keyword_only_arguments: false,
-        enable_positional_only_arguments: false,
-        enable_types: DialectTypes::Disable,
-        enable_load_reexport: false,
-        enable_top_level_stmt: true,
-        enable_f_strings: true,
-        ..Dialect::Standard
-    }
-}

src/eval/recipe.rs

@@ -1,202 +0,0 @@
-use std::cell::Cell;
-
-use allocative::Allocative;
-use starlark::{
-    environment::{GlobalsBuilder, Methods, MethodsBuilder, MethodsStatic},
-    eval::Evaluator,
-    starlark_module, starlark_simple_value,
-    typing::Ty,
-    values::{
-        Heap, StarlarkValue, UnpackValue, Value, ValueLike, none::NoneType, tuple::UnpackTuple,
-        type_repr::StarlarkTypeRepr,
-    },
-};
-use starlark_derive::{NoSerialize, ProvidesStaticType, starlark_value};
-
-use crate::{
-    container::{Container, ContainerManager},
-    eval::{Path, UnpackCloned},
-    log,
-    recipe::Source,
-};
-
-#[derive(Debug, Clone, Allocative, NoSerialize, ProvidesStaticType)]
-pub struct TarballSource {
-    url: String,
-    sha256: String,
-    strip_components: u32,
-}
-
-impl std::fmt::Display for TarballSource {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "tarball")
-    }
-}
-
-starlark_simple_value!(TarballSource);
-
-#[starlark_value(type = "tarball")]
-impl<'v> StarlarkValue<'v> for TarballSource {}
-
-impl UnpackCloned for TarballSource {
-    fn unpack_cloned(value: Value<'_>) -> Option<Self> {
-        value.downcast_ref().cloned()
-    }
-}
-
-impl Source for TarballSource {}
-
-#[derive(Debug, Clone, Allocative, NoSerialize, ProvidesStaticType)]
-pub struct Metadata {
-    maintainer: Option<String>,
-    description: Option<String>,
-    license: Option<String>,
-    website: Option<String>,
-}
-
-impl std::fmt::Display for Metadata {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "metadata")
-    }
-}
-
-starlark_simple_value!(Metadata);
-
-#[starlark_value(type = "metadata")]
-impl<'v> StarlarkValue<'v> for Metadata {}
-
-impl UnpackCloned for Metadata {
-    fn unpack_cloned(value: Value<'_>) -> Option<Self> {
-        value.downcast_ref().cloned()
-    }
-}
-
-#[derive(Debug, Clone, Allocative, NoSerialize, ProvidesStaticType)]
-pub struct Context {
-    pub source_dir: Path,
-    pub build_dir: Path,
-    pub jobs: i32,
-}
-
-impl std::fmt::Display for Context {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "context")
-    }
-}
-
-starlark_simple_value!(Context);
-
-#[derive(Debug)]
-struct RunArg(pub String);
-
-impl UnpackValue<'_> for RunArg {
-    type Error = anyhow::Error;
-
-    fn unpack_value_impl(value: Value) -> anyhow::Result<Option<Self>> {
-        Ok(if let Some(str) = value.unpack_str() {
-            Some(RunArg(str.to_owned()))
-        } else if let Some(int) = value.unpack_i32() {
-            Some(RunArg(int.to_string()))
-        } else if let Some(path) = value.downcast_ref::<Path>() {
-            Some(RunArg(path.path().to_str().unwrap_or("").to_string()))
-        } else {
-            None
-        })
-    }
-}
-
-impl StarlarkTypeRepr for RunArg {
-    type Canonical = Self;
-
-    fn starlark_type_repr() -> starlark::typing::Ty {
-        Ty::string()
-    }
-}
-
-#[derive(ProvidesStaticType)]
-pub struct ContainerManagerWrapper<'a>(pub &'a ContainerManager);
-
-#[starlark_module]
-fn context_methods(b: &mut MethodsBuilder) {
-    fn run(
-        #[starlark(this)] this: &Context,
-        #[starlark(args)] args: UnpackTuple<RunArg>,
-        eval: &mut Evaluator,
-    ) -> anyhow::Result<NoneType> {
-        let ContainerManagerWrapper(container_manager) = eval
-            .extra
-            .and_then(|extra| extra.downcast_ref())
-            .ok_or_else(|| anyhow::anyhow!("`config` called outside of config.star"))?;
-
-        let argv = args.items.iter().map(|x| x.0.as_str()).collect::<Vec<_>>();
-
-        log!("run", "Running command: {argv:?}");
-
-        container_manager
-            .container("changeme")? // TODO
-            .exec(argv, [], std::path::Path::new("/"))?;
-
-        Ok(NoneType)
-    }
-}
-
-#[starlark_value(type = "context")]
-impl<'v> StarlarkValue<'v> for Context {
-    fn get_methods() -> Option<&'static Methods> {
-        static RES: MethodsStatic = MethodsStatic::new();
-        RES.methods(context_methods)
-    }
-
-    fn has_attr(&self, attr: &str, _heap: &Heap) -> bool {
-        match attr {
-            "source_dir" => true,
-            "build_dir" => true,
-            "jobs" => true,
-            _ => false,
-        }
-    }
-
-    fn get_attr(&self, attr: &str, heap: &'v Heap) -> Option<Value<'v>> {
-        match attr {
-            "source_dir" => Some(heap.alloc(self.source_dir.clone())),
-            "build_dir" => Some(heap.alloc(self.build_dir.clone())),
-            "jobs" => Some(heap.alloc(self.jobs)),
-            _ => None,
-        }
-    }
-}
-
-impl UnpackCloned for Context {
-    fn unpack_cloned(value: Value<'_>) -> Option<Self> {
-        value.downcast_ref().cloned()
-    }
-}
-
-#[starlark_module]
-pub fn recipe_globals(b: &mut GlobalsBuilder) {
-    fn tarball(
-        #[starlark(require = named)] url: &str,
-        #[starlark(require = named)] sha256: &str,
-        #[starlark(require = named, default = 0)] strip_components: u32,
-    ) -> anyhow::Result<TarballSource> {
-        Ok(TarballSource {
-            url: url.to_string(),
-            sha256: sha256.to_string(),
-            strip_components,
-        })
-    }
-
-    fn meta(
-        #[starlark(require = named)] maintainer: Option<&str>,
-        #[starlark(require = named)] description: Option<&str>,
-        #[starlark(require = named)] license: Option<&str>,
-        #[starlark(require = named)] website: Option<&str>,
-    ) -> anyhow::Result<Metadata> {
-        Ok(Metadata {
-            maintainer: maintainer.map(|x| x.to_string()),
-            description: description.map(|x| x.to_string()),
-            license: license.map(|x| x.to_string()),
-            website: website.map(|x| x.to_string()),
-        })
-    }
-}

src/eval/types.rs

@@ -1,64 +0,0 @@
-use allocative::Allocative;
-use starlark::{
-    environment::GlobalsBuilder,
-    starlark_module, starlark_simple_value,
-    values::{Heap, StarlarkValue, Value, ValueLike},
-};
-use starlark_derive::{NoSerialize, ProvidesStaticType, starlark_value};
-use std::path::{Path as StdPath, PathBuf};
-
-#[derive(Debug, Clone, Allocative, NoSerialize, ProvidesStaticType)]
-pub struct Path {
-    inner: PathBuf,
-}
-
-impl Path {
-    pub fn new(value: impl Into<PathBuf>) -> Self {
-        Self {
-            inner: value.into(),
-        }
-    }
-
-    pub fn path(&self) -> &StdPath {
-        &self.inner
-    }
-}
-
-impl std::fmt::Display for Path {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "path({:?})", self.inner)
-    }
-}
-
-starlark_simple_value!(Path);
-
-#[starlark_value(type = "path")]
-impl<'v> StarlarkValue<'v> for Path {
-    fn div(&self, other: Value<'v>, heap: &'v Heap) -> starlark::Result<Value<'v>> {
-        let rhs = if let Some(str) = other.unpack_str() {
-            str.to_string()
-        } else if let Some(path) = other.downcast_ref::<Path>() {
-            path.inner.to_str().unwrap_or("").to_string()
-        } else {
-            return Err(starlark::Error::new_other(anyhow::anyhow!(
-                "expected a `string` or `path`, got `{}`",
-                other.get_type()
-            )));
-        };
-
-        Ok(heap.alloc(Path {
-            inner: self
-                .inner
-                .join(rhs.trim_start_matches(std::path::MAIN_SEPARATOR_STR)),
-        }))
-    }
-}
-
-#[starlark_module]
-pub fn types_globals(b: &mut GlobalsBuilder) {
-    fn path(value: &str) -> anyhow::Result<Path> {
-        Ok(Path {
-            inner: PathBuf::from(value),
-        })
-    }
-}

src/graph.rs

@@ -0,0 +1,385 @@
+use std::{
+    collections::{BTreeMap, BTreeSet},
+    fmt, fs,
+    path::Path,
+};
+
+use anyhow::bail;
+
+use crate::{
+    layout::Layout,
+    recipe::{OutputPackage, Recipe, RecipeKind, RecipeSet},
+};
+
+#[derive(Clone, Debug, Eq, Ord, PartialEq, PartialOrd)]
+pub enum TaskId {
+    FetchSources(String),
+    PrepareSources(String),
+    ConfigureRecipe(String),
+    BuildRecipe(String),
+    InstallPackageFiles(String),
+    ProduceApk(String),
+    InstallHostRecipe(String),
+}
+
+impl fmt::Display for TaskId {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::FetchSources(recipe) => write!(f, "fetch sources {recipe}"),
+            Self::PrepareSources(recipe) => write!(f, "prepare sources {recipe}"),
+            Self::ConfigureRecipe(recipe) => write!(f, "configure {recipe}"),
+            Self::BuildRecipe(recipe) => write!(f, "build {recipe}"),
+            Self::InstallPackageFiles(output) => write!(f, "install package files {output}"),
+            Self::ProduceApk(output) => write!(f, "produce apk {output}"),
+            Self::InstallHostRecipe(recipe) => write!(f, "install host recipe {recipe}"),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub struct TaskPlan {
+    dependencies: BTreeMap<TaskId, Vec<TaskId>>,
+    order: Vec<TaskId>,
+}
+
+impl TaskPlan {
+    pub fn order(&self) -> &[TaskId] {
+        &self.order
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.order.is_empty()
+    }
+
+    pub fn dependency_count(&self) -> usize {
+        self.dependencies.values().map(Vec::len).sum()
+    }
+
+    #[cfg(test)]
+    pub fn dependencies(&self, task: &TaskId) -> Option<&[TaskId]> {
+        self.dependencies.get(task).map(Vec::as_slice)
+    }
+}
+
+pub struct TaskPlanner<'a> {
+    layout: Layout<'a>,
+    recipes: &'a RecipeSet,
+    force: bool,
+    dependencies: BTreeMap<TaskId, Vec<TaskId>>,
+    inactive: BTreeSet<TaskId>,
+    visiting: BTreeSet<TaskId>,
+    visited: BTreeSet<TaskId>,
+}
+
+impl<'a> TaskPlanner<'a> {
+    pub fn new(root: &'a Path, arch: &'a str, recipes: &'a RecipeSet) -> Self {
+        Self {
+            layout: Layout::new(root, arch),
+            recipes,
+            force: false,
+            dependencies: BTreeMap::new(),
+            inactive: BTreeSet::new(),
+            visiting: BTreeSet::new(),
+            visited: BTreeSet::new(),
+        }
+    }
+
+    pub fn build_plan(mut self, requests: &[String], force: bool) -> anyhow::Result<TaskPlan> {
+        self.force = force;
+        for request in requests {
+            let recipe = self.recipes.recipe(request)?;
+            match recipe.kind() {
+                RecipeKind::Package => {
+                    for output in recipe.outputs() {
+                        self.visit(TaskId::ProduceApk(output.key()))?;
+                    }
+                }
+                RecipeKind::HostPackage => {
+                    self.visit(TaskId::InstallHostRecipe(recipe.key()))?;
+                }
+            }
+        }
+        self.into_plan()
+    }
+
+    pub fn fetch_plan(mut self, requests: &[String]) -> anyhow::Result<TaskPlan> {
+        for request in requests {
+            let recipe = self.recipes.recipe(request)?;
+            self.visit(TaskId::FetchSources(recipe.key()))?;
+        }
+        self.into_plan()
+    }
+
+    fn visit(&mut self, task: TaskId) -> anyhow::Result<()> {
+        if self.visited.contains(&task) || self.inactive.contains(&task) {
+            return Ok(());
+        }
+        if !self.is_active(&task)? {
+            self.inactive.insert(task);
+            return Ok(());
+        }
+        if !self.visiting.insert(task.clone()) {
+            bail!("task dependency cycle involving `{task}`");
+        }
+
+        let dependencies = self.dependencies(&task)?;
+        let mut active_dependencies = Vec::new();
+        for dependency in dependencies {
+            self.visit(dependency.clone())?;
+            if self.dependencies.contains_key(&dependency) {
+                active_dependencies.push(dependency);
+            }
+        }
+
+        self.visiting.remove(&task);
+        self.visited.insert(task.clone());
+        self.dependencies.insert(task, active_dependencies);
+        Ok(())
+    }
+
+    fn into_plan(self) -> anyhow::Result<TaskPlan> {
+        let order = recipe_contiguous_order(&self.dependencies, self.recipes)?;
+        Ok(TaskPlan {
+            dependencies: self.dependencies,
+            order,
+        })
+    }
+
+    fn dependencies(&self, task: &TaskId) -> anyhow::Result<Vec<TaskId>> {
+        match task {
+            TaskId::FetchSources(_) => Ok(Vec::new()),
+            TaskId::PrepareSources(recipe) => Ok(vec![TaskId::FetchSources(recipe.clone())]),
+            TaskId::ConfigureRecipe(recipe) => {
+                let recipe = self.recipes.recipe(recipe)?;
+                let mut deps = vec![TaskId::PrepareSources(recipe.key())];
+                deps.extend(
+                    recipe
+                        .host_deps()
+                        .iter()
+                        .map(|dep| TaskId::InstallHostRecipe(RecipeKind::HostPackage.key(dep))),
+                );
+                deps.extend(
+                    recipe
+                        .build_deps()
+                        .iter()
+                        .chain(recipe.deps().iter())
+                        .map(|dep| TaskId::ProduceApk(dep.clone())),
+                );
+                Ok(deps)
+            }
+            TaskId::BuildRecipe(recipe) => Ok(vec![TaskId::ConfigureRecipe(recipe.clone())]),
+            TaskId::InstallPackageFiles(output) => {
+                let output = self.recipes.output(output)?;
+                Ok(vec![TaskId::BuildRecipe(output.recipe().to_owned())])
+            }
+            TaskId::ProduceApk(output) => {
+                let output = self.recipes.output(output)?;
+                let recipe = self.recipes.recipe(output.recipe())?;
+                let mut deps = vec![TaskId::InstallPackageFiles(output.key())];
+                deps.extend(
+                    recipe
+                        .deps()
+                        .iter()
+                        .chain(recipe.run_deps().iter())
+                        .map(|dep| TaskId::ProduceApk(dep.clone())),
+                );
+                Ok(deps)
+            }
+            TaskId::InstallHostRecipe(recipe) => {
+                self.recipes.recipe(recipe)?;
+                Ok(vec![TaskId::BuildRecipe(recipe.clone())])
+            }
+        }
+    }
+
+    fn is_active(&self, task: &TaskId) -> anyhow::Result<bool> {
+        match task {
+            TaskId::FetchSources(recipe) => self.fetch_sources_active(self.recipes.recipe(recipe)?),
+            TaskId::PrepareSources(recipe) => {
+                self.prepare_sources_active(self.recipes.recipe(recipe)?)
+            }
+            TaskId::ConfigureRecipe(recipe) => {
+                self.recipe_task_active(self.recipes.recipe(recipe)?, "configure")
+            }
+            TaskId::BuildRecipe(recipe) => {
+                self.recipe_task_active(self.recipes.recipe(recipe)?, "build")
+            }
+            TaskId::InstallPackageFiles(output) => {
+                let output = self.recipes.output(output)?;
+                let recipe = self.recipes.recipe(output.recipe())?;
+                Ok(self.output_task_active(recipe, output, "install")?
+                    || self.produce_apk_active(recipe, output)?)
+            }
+            TaskId::ProduceApk(output) => {
+                let output = self.recipes.output(output)?;
+                let recipe = self.recipes.recipe(output.recipe())?;
+                self.produce_apk_active(recipe, output)
+            }
+            TaskId::InstallHostRecipe(recipe) => {
+                let recipe = self.recipes.recipe(recipe)?;
+                self.install_host_recipe_active(recipe)
+            }
+        }
+    }
+
+    fn fetch_sources_active(&self, recipe: &Recipe) -> anyhow::Result<bool> {
+        Ok(recipe.sources().entries().iter().any(|(_, source)| {
+            source.is_unknown_cache_key()
+                || !self.layout.source_cache_path(source.cache_key()).exists()
+        }))
+    }
+
+    fn prepare_sources_active(&self, recipe: &Recipe) -> anyhow::Result<bool> {
+        if self.force {
+            return Ok(true);
+        }
+        let want_version = format!("{}-r{}", recipe.version(), recipe.revision());
+        if fs::read_to_string(self.layout.source_stamp(recipe, "version"))
+            .ok()
+            .as_deref()
+            != Some(want_version.as_str())
+        {
+            return Ok(true);
+        }
+        if self.layout.recipe_has_patches(recipe)?
+            && !self.layout.source_stamp(recipe, "patched").exists()
+        {
+            return Ok(true);
+        }
+        Ok(false)
+    }
+
+    fn recipe_task_active(&self, recipe: &Recipe, kind: &str) -> anyhow::Result<bool> {
+        if self.force {
+            return Ok(true);
+        }
+        Ok(
+            fs::read_to_string(self.layout.recipe_task_stamp(recipe, kind))
+                .ok()
+                .as_deref()
+                != Some(self.layout.recipe_fingerprint(recipe)?.as_str()),
+        )
+    }
+
+    fn output_task_active(
+        &self,
+        recipe: &Recipe,
+        output: &OutputPackage,
+        kind: &str,
+    ) -> anyhow::Result<bool> {
+        if self.force {
+            return Ok(true);
+        }
+        Ok(
+            fs::read_to_string(self.layout.output_task_stamp(output, kind))
+                .ok()
+                .as_deref()
+                != Some(self.layout.output_fingerprint(recipe, output)?.as_str()),
+        )
+    }
+
+    fn produce_apk_active(&self, recipe: &Recipe, output: &OutputPackage) -> anyhow::Result<bool> {
+        if self.force {
+            return Ok(true);
+        }
+        if !self.layout.apk_path(recipe, output).exists() {
+            return Ok(true);
+        }
+        Ok(
+            fs::read_to_string(self.layout.output_task_stamp(output, "apk"))
+                .ok()
+                .as_deref()
+                != Some(self.layout.output_fingerprint(recipe, output)?.as_str()),
+        )
+    }
+
+    fn install_host_recipe_active(&self, recipe: &Recipe) -> anyhow::Result<bool> {
+        if self.force {
+            return Ok(true);
+        }
+        if !self.layout.host_install_dir(recipe).exists() {
+            return Ok(true);
+        }
+        Ok(
+            fs::read_to_string(self.layout.recipe_task_stamp(recipe, "host-install"))
+                .ok()
+                .as_deref()
+                != Some(self.layout.recipe_fingerprint(recipe)?.as_str()),
+        )
+    }
+}
+
+fn recipe_contiguous_order(
+    dependencies: &BTreeMap<TaskId, Vec<TaskId>>,
+    recipes: &RecipeSet,
+) -> anyhow::Result<Vec<TaskId>> {
+    let total = dependencies.len();
+    let mut remaining: BTreeMap<TaskId, BTreeSet<TaskId>> = dependencies
+        .iter()
+        .map(|(task, deps)| (task.clone(), deps.iter().cloned().collect()))
+        .collect();
+
+    let mut dependents: BTreeMap<TaskId, Vec<TaskId>> = BTreeMap::new();
+    for (task, deps) in dependencies {
+        for dep in deps {
+            dependents
+                .entry(dep.clone())
+                .or_default()
+                .push(task.clone());
+        }
+    }
+
+    let mut order = Vec::with_capacity(total);
+    let mut current_recipe: Option<String> = None;
+    while order.len() < total {
+        let next = pick_next(&remaining, current_recipe.as_deref(), recipes)?;
+        let slug = task_recipe_slug(&next, recipes)?;
+        current_recipe = Some(slug);
+        remaining.remove(&next);
+        if let Some(children) = dependents.get(&next) {
+            for child in children {
+                if let Some(deps) = remaining.get_mut(child) {
+                    deps.remove(&next);
+                }
+            }
+        }
+        order.push(next);
+    }
+    Ok(order)
+}
+
+fn pick_next(
+    remaining: &BTreeMap<TaskId, BTreeSet<TaskId>>,
+    current_recipe: Option<&str>,
+    recipes: &RecipeSet,
+) -> anyhow::Result<TaskId> {
+    let mut fallback: Option<TaskId> = None;
+    for (task, deps) in remaining {
+        if !deps.is_empty() {
+            continue;
+        }
+        if let Some(active) = current_recipe {
+            let slug = task_recipe_slug(task, recipes)?;
+            if slug == active {
+                return Ok(task.clone());
+            }
+        }
+        if fallback.is_none() {
+            fallback = Some(task.clone());
+        }
+    }
+    fallback.ok_or_else(|| anyhow::anyhow!("task dependency cycle detected"))
+}
+
+pub fn task_recipe_slug(task: &TaskId, recipes: &RecipeSet) -> anyhow::Result<String> {
+    Ok(match task {
+        TaskId::FetchSources(recipe)
+        | TaskId::PrepareSources(recipe)
+        | TaskId::ConfigureRecipe(recipe)
+        | TaskId::BuildRecipe(recipe)
+        | TaskId::InstallHostRecipe(recipe) => recipe.clone(),
+        TaskId::InstallPackageFiles(output) | TaskId::ProduceApk(output) => {
+            recipes.output(output)?.recipe().to_owned()
+        }
+    })
+}

src/layout.rs

@@ -0,0 +1,131 @@
+use std::{
+    fs,
+    path::{Path, PathBuf},
+};
+
+use anyhow::Context;
+use sha2::{Digest, Sha256};
+
+use crate::recipe::{OutputPackage, Recipe};
+
+pub struct Layout<'a> {
+    pub root: &'a Path,
+    pub arch: &'a str,
+}
+
+impl<'a> Layout<'a> {
+    pub fn new(root: &'a Path, arch: &'a str) -> Self {
+        Self { root, arch }
+    }
+
+    pub fn source_cache_dir(&self) -> PathBuf {
+        self.root.join("build/cache/sources")
+    }
+
+    pub fn source_cache_path(&self, key: &str) -> PathBuf {
+        self.source_cache_dir().join(key)
+    }
+
+    pub fn source_workdir(&self, recipe: &Recipe) -> PathBuf {
+        self.root.join("build/sources").join(recipe.slug())
+    }
+
+    pub fn build_workdir(&self, recipe: &Recipe) -> PathBuf {
+        self.root.join("build/builds").join(recipe.slug())
+    }
+
+    pub fn host_install_dir(&self, recipe: &Recipe) -> PathBuf {
+        self.root
+            .join("build/host-pkgs")
+            .join(recipe.slug())
+            .join("usr/local")
+    }
+
+    pub fn host_install_root(&self, recipe: &Recipe) -> PathBuf {
+        self.root.join("build/host-pkgs").join(recipe.slug())
+    }
+
+    pub fn apk_path(&self, recipe: &Recipe, output: &OutputPackage) -> PathBuf {
+        self.root.join("build/pkgs").join(self.arch).join(format!(
+            "{}-{}-r{}.apk",
+            output.name(),
+            recipe.version(),
+            recipe.revision()
+        ))
+    }
+
+    pub fn source_stamp(&self, recipe: &Recipe, kind: &str) -> PathBuf {
+        self.root
+            .join("build/sources")
+            .join(format!("{}.{kind}", recipe.slug()))
+    }
+
+    pub fn recipe_task_stamp(&self, recipe: &Recipe, kind: &str) -> PathBuf {
+        self.root
+            .join("build/tasks")
+            .join(format!("{}.{kind}", recipe.slug()))
+    }
+
+    pub fn output_task_stamp(&self, output: &OutputPackage, kind: &str) -> PathBuf {
+        self.root
+            .join("build/tasks")
+            .join(format!("{}.{kind}", output.key().replace(':', "-")))
+    }
+
+    pub fn recipe_fingerprint(&self, recipe: &Recipe) -> anyhow::Result<String> {
+        let mut hasher = Sha256::new();
+        hasher.update(self.arch.as_bytes());
+        hasher.update(recipe.key().as_bytes());
+        hasher.update(recipe.version().as_bytes());
+        hasher.update(recipe.revision().to_le_bytes());
+        hasher.update(
+            fs::read(recipe.path())
+                .with_context(|| format!("reading recipe {}", recipe.path().display()))?,
+        );
+        for (name, source) in recipe.sources().entries() {
+            hasher.update(name.unwrap_or("").as_bytes());
+            hasher.update(source.url().as_bytes());
+            hasher.update(source.cache_key().as_bytes());
+        }
+        for patch in self.recipe_patches(recipe)? {
+            hasher.update(patch.display().to_string().as_bytes());
+            hasher
+                .update(fs::read(&patch).with_context(|| format!("reading {}", patch.display()))?);
+        }
+        Ok(hex::encode(hasher.finalize()))
+    }
+
+    pub fn output_fingerprint(
+        &self,
+        recipe: &Recipe,
+        output: &OutputPackage,
+    ) -> anyhow::Result<String> {
+        let mut hasher = Sha256::new();
+        hasher.update(self.recipe_fingerprint(recipe)?.as_bytes());
+        hasher.update(output.key().as_bytes());
+        Ok(hex::encode(hasher.finalize()))
+    }
+
+    pub fn recipe_has_patches(&self, recipe: &Recipe) -> anyhow::Result<bool> {
+        Ok(!self.recipe_patches(recipe)?.is_empty())
+    }
+
+    pub fn recipe_patches(&self, recipe: &Recipe) -> anyhow::Result<Vec<PathBuf>> {
+        let patches_dir = recipe.dir().join("patches");
+        if !patches_dir.exists() {
+            return Ok(Vec::new());
+        }
+        let mut patches = Vec::new();
+        for entry in fs::read_dir(&patches_dir)
+            .with_context(|| format!("reading patches directory {}", patches_dir.display()))?
+        {
+            let entry = entry?;
+            let path = entry.path();
+            if path.is_file() {
+                patches.push(path);
+            }
+        }
+        patches.sort();
+        Ok(patches)
+    }
+}

src/log.rs

@@ -2,19 +2,25 @@ use std::{io::IsTerminal, sync::LazyLock};
 
 static IS_STDERR_TERMINAL: LazyLock<bool> = LazyLock::new(|| std::io::stderr().is_terminal());
 
-pub fn __emit(color: &str, action: &str, args: std::fmt::Arguments) {
-    const ARROW: &str = "==>";
+const ARROW: &str = "==>";
 
+fn emit(color: &str, action: &str, details: &str) {
     if *IS_STDERR_TERMINAL {
-        eprintln!("\x1b[{color}m{ARROW}\x1b[0m \x1b[1m{action}\x1b[0m {args}");
+        eprintln!("\x1b[{color}m{ARROW} \x1b[1m{action} \x1b[0m{details}");
     } else {
-        eprintln!("{ARROW} {action} {args}");
+        eprintln!("{ARROW} {action} {details}");
     }
 }
 
-#[macro_export]
-macro_rules! log {
-    ($action:literal, $($arg:tt)*) => {{
-        $crate::log::__emit("1;34", $action, format_args!($($arg)*));
-    }};
+pub fn step(action: &str, details: &str) {
+    emit("1;34", action, details);
+}
+
+pub fn skip(action: &str, details: &str) {
+    emit("1;33", action, details);
+}
+
+#[allow(dead_code)]
+pub fn info(action: &str, details: &str) {
+    emit("1;32", action, details);
 }

src/main.rs

@@ -1,136 +1,15 @@
-use crate::{
-    container::{ContainerManager, PodmanRuntime},
-    plan::{Plan, PlanKey},
-    recipe::{PackageRecipe, RecipeSet, SourceRecipe, ToolRecipe},
-};
-
-use std::{path::Path, sync::Arc};
-
+mod builder;
 mod cli;
+mod config;
 mod container;
 mod eval;
+mod graph;
+mod layout;
 mod log;
-mod plan;
+mod options;
+mod phase;
 mod recipe;
 
 fn main() -> anyhow::Result<()> {
     cli::run()
-
-    // let podman_runtime = Arc::new(PodmanRuntime::new()?);
-    // let mut container_manager = ContainerManager::new(podman_runtime);
-
-    // container_manager.container("example")?.exec(
-    //     vec!["sh", "-c", "uname -a && id"],
-    //     vec![],
-    //     Path::new("/"),
-    // )?;
-
-    // let mut recipes = RecipeSet::default();
-
-    // recipes.load_recipes(Path::new("./recipes"), Path::new("./host-recipes"))?;
-
-    // recipes.add_source(
-    //     "binutils-2.46",
-    //     SourceRecipe {
-    //         name: "binutils-2.46".into(),
-    //     },
-    // );
-
-    // recipes.add_source(
-    //     "gcc-16.1.0",
-    //     SourceRecipe {
-    //         name: "gcc-16.1.0".into(),
-    //     },
-    // );
-
-    // recipes.add_source(
-    //     "linux-7.0.9",
-    //     SourceRecipe {
-    //         name: "linux-7.0.9".into(),
-    //     },
-    // );
-
-    // recipes.add_source(
-    //     "glibc-2.41",
-    //     SourceRecipe {
-    //         name: "glibc-2.41".into(),
-    //     },
-    // );
-
-    // recipes.add_source(
-    //     "bash-5.3",
-    //     SourceRecipe {
-    //         name: "bash-5.3".into(),
-    //     },
-    // );
-
-    // recipes.add_tool(
-    //     "binutils",
-    //     ToolRecipe {
-    //         name: "binutils".into(),
-    //         sources: vec!["binutils-2.46".into()],
-    //         tools_wanted: vec![],
-    //         pkgs_wanted: vec![],
-    //     },
-    // );
-
-    // recipes.add_tool(
-    //     "gcc-bootstrap",
-    //     ToolRecipe {
-    //         name: "gcc-bootstrap".into(),
-    //         sources: vec!["gcc-16.1.0".into()],
-    //         tools_wanted: vec!["binutils".into()],
-    //         pkgs_wanted: vec![],
-    //     },
-    // );
-
-    // recipes.add_tool(
-    //     "gcc",
-    //     ToolRecipe {
-    //         name: "gcc".into(),
-    //         sources: vec!["gcc-16.1.0".into()],
-    //         tools_wanted: vec!["binutils".into()],
-    //         pkgs_wanted: vec!["glibc".into()],
-    //     },
-    // );
-
-    // recipes.add_package(
-    //     "linux-headers",
-    //     PackageRecipe {
-    //         name: "linux-headers".into(),
-    //         sources: vec!["linux-7.0.9".into()],
-    //         tools_wanted: vec![],
-    //         pkgs_wanted: vec![],
-    //     },
-    // );
-
-    // recipes.add_package(
-    //     "glibc",
-    //     PackageRecipe {
-    //         name: "glibc".into(),
-    //         sources: vec!["glibc-2.41".into()],
-    //         tools_wanted: vec!["gcc-bootstrap".into()],
-    //         pkgs_wanted: vec!["linux-headers".into()],
-    //     },
-    // );
-
-    // recipes.add_package(
-    //     "bash",
-    //     PackageRecipe {
-    //         name: "bash".into(),
-    //         sources: vec!["bash-5.3".into()],
-    //         tools_wanted: vec!["gcc".into()],
-    //         pkgs_wanted: vec!["glibc".into()],
-    //     },
-    // );
-
-    // let mut plan = Plan::new(&recipes);
-
-    // plan.add_wanted(PlanKey::PkgPackage(
-    //     recipes.package("bash").expect("back package"),
-    // ));
-
-    // println!("{:#?}", plan.steps()?);
-
-    // Ok(())
 }

src/options.rs

@@ -0,0 +1,35 @@
+use allocative::Allocative;
+use starlark::values::{Heap, OwnedFrozenValue, StarlarkValue, Value};
+use starlark_derive::{NoSerialize, ProvidesStaticType, starlark_value};
+use std::collections::HashMap;
+
+#[derive(Debug, Clone, Allocative, ProvidesStaticType, NoSerialize)]
+pub struct Options {
+    entries: HashMap<String, OwnedFrozenValue>,
+}
+
+impl Options {
+    pub fn new(entries: HashMap<String, OwnedFrozenValue>) -> Self {
+        Self { entries }
+    }
+}
+
+impl std::fmt::Display for Options {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "options")
+    }
+}
+
+starlark::starlark_simple_value!(Options);
+
+#[starlark_value(type = "options")]
+impl<'v> StarlarkValue<'v> for Options {
+    fn get_attr(&self, attribute: &str, _heap: &'v Heap) -> Option<Value<'v>> {
+        let owned = self.entries.get(attribute)?;
+        // SAFETY: `self` is kept alive by the module heap into which it was
+        // allocated, and `owned` holds an Arc to its source frozen heap. The
+        // returned Value therefore remains valid for as long as the receiving
+        // module is alive.
+        Some(unsafe { owned.unchecked_frozen_value() }.to_value())
+    }
+}

src/phase.rs

@@ -0,0 +1,296 @@
+use std::{cell::RefCell, collections::BTreeMap, rc::Rc};
+
+use allocative::Allocative;
+use anyhow::anyhow;
+use starlark::{
+    collections::SmallMap,
+    environment::{Methods, MethodsBuilder, MethodsStatic, Module},
+    eval::Evaluator,
+    values::{Heap, OwnedFrozenValue, StarlarkValue, Value, list::UnpackList, none::NoneType},
+};
+use starlark_derive::{NoSerialize, ProvidesStaticType, starlark_module, starlark_value};
+
+use crate::container::Container;
+
+thread_local! {
+    static CURRENT: RefCell<Option<PhaseRuntime>> = const { RefCell::new(None) };
+}
+
+#[derive(Clone)]
+pub struct PhaseRuntime {
+    pub container: Rc<RefCell<Container>>,
+    pub base_path: String,
+    pub base_env: Vec<(String, String)>,
+}
+
+pub struct PhaseRuntimeGuard;
+
+impl PhaseRuntimeGuard {
+    pub fn enter(runtime: PhaseRuntime) -> Self {
+        CURRENT.with(|cell| {
+            let prev = cell.borrow_mut().replace(runtime);
+            assert!(prev.is_none(), "phase runtime already set");
+        });
+        Self
+    }
+}
+
+impl Drop for PhaseRuntimeGuard {
+    fn drop(&mut self) {
+        CURRENT.with(|cell| {
+            cell.borrow_mut().take();
+        });
+    }
+}
+
+fn with_current<R>(f: impl FnOnce(&PhaseRuntime) -> R) -> anyhow::Result<R> {
+    CURRENT.with(|cell| {
+        let borrow = cell.borrow();
+        let runtime = borrow
+            .as_ref()
+            .ok_or_else(|| anyhow!("ctx.run called outside of a phase invocation"))?;
+        Ok(f(runtime))
+    })
+}
+
+#[derive(Debug, Clone, Allocative, ProvidesStaticType, NoSerialize)]
+pub struct SourceDir {
+    default: String,
+    entries: BTreeMap<String, String>,
+}
+
+impl SourceDir {
+    pub fn single(path: impl Into<String>) -> Self {
+        Self {
+            default: path.into(),
+            entries: BTreeMap::new(),
+        }
+    }
+
+    pub fn named<I, K, V>(entries: I) -> Self
+    where
+        I: IntoIterator<Item = (K, V)>,
+        K: Into<String>,
+        V: Into<String>,
+    {
+        let entries: BTreeMap<String, String> = entries
+            .into_iter()
+            .map(|(k, v)| (k.into(), v.into()))
+            .collect();
+        let default = entries
+            .values()
+            .next()
+            .cloned()
+            .unwrap_or_else(|| "/sources".to_owned());
+        Self { default, entries }
+    }
+}
+
+impl std::fmt::Display for SourceDir {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(&self.default)
+    }
+}
+
+starlark::starlark_simple_value!(SourceDir);
+
+#[starlark_value(type = "source_dir")]
+impl<'v> StarlarkValue<'v> for SourceDir {
+    fn at(&self, index: Value<'v>, heap: &'v Heap) -> starlark::Result<Value<'v>> {
+        let key = index.unpack_str().ok_or_else(|| {
+            starlark::Error::new_other(anyhow!("source_dir index must be a string"))
+        })?;
+        let path = self.entries.get(key).ok_or_else(|| {
+            starlark::Error::new_other(anyhow!(
+                "no source named `{key}` (available: {})",
+                if self.entries.is_empty() {
+                    "<none>".to_owned()
+                } else {
+                    self.entries
+                        .keys()
+                        .map(String::as_str)
+                        .collect::<Vec<_>>()
+                        .join(", ")
+                }
+            ))
+        })?;
+        Ok(heap.alloc(path.as_str()))
+    }
+
+    fn add(&self, rhs: Value<'v>, heap: &'v Heap) -> Option<starlark::Result<Value<'v>>> {
+        let suffix = rhs.unpack_str()?;
+        Some(Ok(heap.alloc(format!("{}{}", self.default, suffix))))
+    }
+
+    fn radd(&self, lhs: Value<'v>, heap: &'v Heap) -> Option<starlark::Result<Value<'v>>> {
+        let prefix = lhs.unpack_str()?;
+        Some(Ok(heap.alloc(format!("{}{}", prefix, self.default))))
+    }
+}
+
+#[derive(Debug, Clone, Allocative, ProvidesStaticType, NoSerialize)]
+pub struct PhaseContext {
+    source_dir: SourceDir,
+    build_dir: String,
+    prefix: String,
+    sysroot: String,
+    jobs: i32,
+}
+
+impl PhaseContext {
+    pub fn new(source_dir: SourceDir, prefix: &str, jobs: i32) -> Self {
+        Self {
+            source_dir,
+            build_dir: "/build".to_owned(),
+            prefix: prefix.to_owned(),
+            sysroot: "/sysroot".to_owned(),
+            jobs,
+        }
+    }
+}
+
+impl std::fmt::Display for PhaseContext {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "ctx")
+    }
+}
+
+starlark::starlark_simple_value!(PhaseContext);
+
+#[starlark_value(type = "phase_context")]
+impl<'v> StarlarkValue<'v> for PhaseContext {
+    fn get_attr(&self, attr: &str, heap: &'v Heap) -> Option<Value<'v>> {
+        Some(match attr {
+            "source_dir" => heap.alloc(self.source_dir.clone()),
+            "build_dir" => heap.alloc(self.build_dir.as_str()),
+            "prefix" => heap.alloc(self.prefix.as_str()),
+            "sysroot" => heap.alloc(self.sysroot.as_str()),
+            "jobs" => heap.alloc(self.jobs),
+            _ => return None,
+        })
+    }
+
+    fn has_attr(&self, attr: &str, _heap: &'v Heap) -> bool {
+        matches!(
+            attr,
+            "source_dir" | "build_dir" | "prefix" | "sysroot" | "jobs" | "run"
+        )
+    }
+
+    fn dir_attr(&self) -> Vec<String> {
+        [
+            "source_dir",
+            "build_dir",
+            "prefix",
+            "sysroot",
+            "jobs",
+            "run",
+        ]
+        .into_iter()
+        .map(String::from)
+        .collect()
+    }
+
+    fn get_methods() -> Option<&'static Methods> {
+        static RES: MethodsStatic = MethodsStatic::new();
+        RES.methods(phase_context_methods)
+    }
+}
+
+#[starlark_module]
+fn phase_context_methods(builder: &mut MethodsBuilder) {
+    fn run<'v>(
+        #[starlark(this)] _this: Value<'v>,
+        #[starlark(require = pos)] argv: UnpackList<String>,
+        #[starlark(require = named)] env: Option<SmallMap<String, String>>,
+    ) -> anyhow::Result<NoneType> {
+        run_in_container(&argv.items, env.unwrap_or_default())?;
+        Ok(NoneType)
+    }
+}
+
+fn run_in_container(
+    argv: &[String],
+    env_overrides: SmallMap<String, String>,
+) -> anyhow::Result<()> {
+    let (container, env) = with_current(|runtime| {
+        let mut env: Vec<(String, String)> = runtime
+            .base_env
+            .iter()
+            .cloned()
+            .map(|(k, v)| {
+                if k == "PATH" {
+                    (k, runtime.base_path.clone())
+                } else {
+                    (k, v)
+                }
+            })
+            .collect();
+        for (k, v) in env_overrides {
+            if let Some(slot) = env.iter_mut().find(|(existing, _)| existing == &k) {
+                slot.1 = v;
+            } else {
+                env.push((k, v));
+            }
+        }
+        (runtime.container.clone(), env)
+    })?;
+    container.borrow().exec(argv, &env, "/build")
+}
+
+#[derive(Debug, Clone, Allocative, ProvidesStaticType, NoSerialize)]
+pub struct PackageContext {
+    dest_dir: String,
+}
+
+impl PackageContext {
+    pub fn new(dest_dir: String) -> Self {
+        Self { dest_dir }
+    }
+}
+
+impl std::fmt::Display for PackageContext {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "pkg")
+    }
+}
+
+starlark::starlark_simple_value!(PackageContext);
+
+#[starlark_value(type = "package_context")]
+impl<'v> StarlarkValue<'v> for PackageContext {
+    fn get_attr(&self, attr: &str, heap: &'v Heap) -> Option<Value<'v>> {
+        match attr {
+            "dest_dir" => Some(heap.alloc(self.dest_dir.as_str())),
+            _ => None,
+        }
+    }
+
+    fn has_attr(&self, attr: &str, _heap: &'v Heap) -> bool {
+        attr == "dest_dir"
+    }
+
+    fn dir_attr(&self) -> Vec<String> {
+        vec!["dest_dir".to_owned()]
+    }
+}
+
+pub fn invoke_phase(func: &OwnedFrozenValue, args: &[PhaseArg]) -> anyhow::Result<()> {
+    let module = Module::new();
+    let mut eval = Evaluator::new(&module);
+    let allocated: Vec<Value<'_>> = args
+        .iter()
+        .map(|arg| match arg {
+            PhaseArg::Ctx(ctx) => module.heap().alloc(ctx.clone()),
+            PhaseArg::Pkg(pkg) => module.heap().alloc(pkg.clone()),
+        })
+        .collect();
+    eval.eval_function(func.value(), &allocated, &[])
+        .map_err(|err| anyhow!("{err}"))?;
+    Ok(())
+}
+
+pub enum PhaseArg {
+    Ctx(PhaseContext),
+    Pkg(PackageContext),
+}

src/plan.rs

@@ -1,222 +0,0 @@
-use crate::recipe::{PackageRecipe, RecipeSet, SourceRecipe, ToolRecipe};
-
-use petgraph::{
-    Direction,
-    graph::{DiGraph, NodeIndex},
-};
-use smallvec::{SmallVec, smallvec};
-use std::{
-    cmp::Reverse,
-    collections::{BinaryHeap, HashMap, HashSet},
-};
-use thiserror::Error;
-
-#[derive(Debug, Error)]
-pub enum PlanError {
-    #[error("missing source recipe '{0}'")]
-    MissingSource(String),
-    #[error("missing tool recipe '{0}'")]
-    MissingTool(String),
-    #[error("missing package recipe '{0}'")]
-    MissingPackage(String),
-    #[error("plan cycle detected")]
-    CycleDetected,
-}
-
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
-pub enum PlanKey {
-    SourceFetch(String),
-    SourcePatch(String),
-    SourcePrepare(String),
-
-    ToolConfigure(String),
-    ToolBuild(String),
-    ToolInstall(String),
-
-    PkgConfigure(String),
-    PkgBuild(String),
-    PkgInstall(String),
-    PkgPackage(String),
-}
-
-impl PlanKey {
-    fn weight(&self) -> i8 {
-        match self {
-            PlanKey::SourceFetch(_) => 0,
-            PlanKey::SourcePatch(_) => 1,
-            PlanKey::SourcePrepare(_) => 2,
-            PlanKey::ToolConfigure(_) => 3,
-            PlanKey::ToolBuild(_) => 4,
-            PlanKey::ToolInstall(_) => 5,
-            PlanKey::PkgConfigure(_) => 6,
-            PlanKey::PkgBuild(_) => 7,
-            PlanKey::PkgInstall(_) => 8,
-            PlanKey::PkgPackage(_) => 9,
-        }
-    }
-
-    fn dependencies(&self, recipes: &RecipeSet) -> Result<SmallVec<[PlanKey; 8]>, PlanError> {
-        match self {
-            PlanKey::SourceFetch(_) => Ok(smallvec![]),
-            PlanKey::SourcePatch(recipe) => Ok(smallvec![PlanKey::SourceFetch(recipe.clone())]),
-            PlanKey::SourcePrepare(recipe) => Ok(smallvec![PlanKey::SourcePatch(recipe.clone())]),
-            PlanKey::ToolConfigure(recipe) => {
-                let recipe = recipes
-                    .tool(recipe)
-                    .ok_or(PlanError::MissingTool(recipe.clone()))?;
-
-                let source_deps = recipe.sources.iter().map(|name| {
-                    recipes
-                        .source(name)
-                        .map(|_| PlanKey::SourcePrepare(name.to_string()))
-                        .ok_or(PlanError::MissingSource(name.to_string()))
-                });
-
-                let tool_deps = recipe.tools_wanted.iter().map(|name| {
-                    recipes
-                        .tool(name)
-                        .map(|_| PlanKey::ToolInstall(name.to_string()))
-                        .ok_or(PlanError::MissingTool(name.to_string()))
-                });
-
-                let pkg_deps = recipe.pkgs_wanted.iter().map(|name| {
-                    recipes
-                        .package(name)
-                        .map(|_| PlanKey::PkgPackage(name.to_string()))
-                        .ok_or(PlanError::MissingPackage(name.to_string()))
-                });
-
-                source_deps.chain(tool_deps).chain(pkg_deps).collect()
-            }
-            PlanKey::ToolBuild(recipe) => Ok(smallvec![PlanKey::ToolConfigure(recipe.clone())]),
-            PlanKey::ToolInstall(recipe) => Ok(smallvec![PlanKey::ToolBuild(recipe.clone())]),
-            PlanKey::PkgConfigure(recipe) => {
-                let recipe = recipes
-                    .package(recipe)
-                    .ok_or(PlanError::MissingPackage(recipe.clone()))?;
-
-                let source_deps = recipe.sources.iter().map(|name| {
-                    recipes
-                        .source(name)
-                        .map(|_| PlanKey::SourcePrepare(name.to_string()))
-                        .ok_or(PlanError::MissingSource(name.to_string()))
-                });
-
-                let tool_deps = recipe.tools_wanted.iter().map(|name| {
-                    recipes
-                        .tool(name)
-                        .map(|_| PlanKey::ToolInstall(name.to_string()))
-                        .ok_or(PlanError::MissingTool(name.to_string()))
-                });
-
-                let pkg_deps = recipe.pkgs_wanted.iter().map(|name| {
-                    recipes
-                        .package(name)
-                        .map(|_| PlanKey::PkgPackage(name.to_string()))
-                        .ok_or(PlanError::MissingPackage(name.to_string()))
-                });
-
-                source_deps.chain(tool_deps).chain(pkg_deps).collect()
-            }
-            PlanKey::PkgBuild(recipe) => Ok(smallvec![PlanKey::PkgConfigure(recipe.clone())]),
-            PlanKey::PkgInstall(recipe) => Ok(smallvec![PlanKey::PkgBuild(recipe.clone())]),
-            PlanKey::PkgPackage(recipe) => Ok(smallvec![PlanKey::PkgInstall(recipe.clone())]),
-        }
-    }
-
-    fn is_active(&self) -> bool {
-        true
-    }
-}
-
-pub struct Plan<'a> {
-    recipes: &'a RecipeSet<'a>,
-    wanted: HashSet<PlanKey>,
-}
-
-impl<'a> Plan<'a> {
-    pub fn new(recipes: &'a RecipeSet) -> Self {
-        Self {
-            recipes,
-            wanted: HashSet::new(),
-        }
-    }
-
-    pub fn add_wanted(&mut self, key: PlanKey) {
-        self.wanted.insert(key);
-    }
-
-    pub fn steps(&self) -> Result<Vec<PlanKey>, PlanError> {
-        let mut stack: Vec<_> = self.wanted.iter().cloned().collect();
-        let mut graph: DiGraph<_, ()> = DiGraph::new();
-        let mut nodes = HashMap::new();
-
-        while let Some(node) = stack.pop() {
-            let node_idx = match nodes.get(&node) {
-                Some(&idx) => idx,
-                None => {
-                    let idx = graph.add_node(node.clone());
-                    nodes.insert(node.clone(), idx);
-                    idx
-                }
-            };
-
-            for dep in node.dependencies(self.recipes)? {
-                let dep_idx = match nodes.get(&dep) {
-                    Some(&idx) => idx,
-                    None => {
-                        let idx = graph.add_node(dep.clone());
-                        nodes.insert(dep.clone(), idx);
-                        stack.push(dep);
-                        idx
-                    }
-                };
-
-                graph.update_edge(dep_idx, node_idx, ());
-            }
-        }
-
-        // petgraph::algo::toposort(&graph, None)
-        //     .and_then(|nodes| {
-        //         Ok(nodes
-        //             .iter()
-        //             .map(|&k| graph[k])
-        //             .filter(|node| node.is_active())
-        //             .collect())
-        //     })
-        //     .map_err(|_| PlanError::CycleDetected)
-
-        let mut in_degree: HashMap<NodeIndex, usize> = graph
-            .node_indices()
-            .map(|i| (i, graph.neighbors_directed(i, Direction::Incoming).count()))
-            .collect();
-
-        let mut heap: BinaryHeap<(Reverse<i8>, NodeIndex)> = in_degree
-            .iter()
-            .filter(|&(_, d)| *d == 0)
-            .map(|(&i, _)| (Reverse(graph[i].weight()), i))
-            .collect();
-
-        let mut result = Vec::with_capacity(graph.node_count());
-
-        while let Some((_, idx)) = heap.pop() {
-            result.push(graph[idx].clone());
-
-            for neighbor in graph.neighbors_directed(idx, Direction::Outgoing) {
-                let d = in_degree.get_mut(&neighbor).unwrap();
-                *d -= 1;
-                if *d == 0 {
-                    heap.push((Reverse(graph[neighbor].weight()), neighbor));
-                }
-            }
-        }
-
-        if result.len() != graph.node_count() {
-            Err(PlanError::CycleDetected)
-        } else {
-            result.retain(|node| node.is_active());
-
-            Ok(result)
-        }
-    }
-}

src/recipe.rs

@@ -1,256 +0,0 @@
-use anyhow::Context;
-use starlark::{
-    environment::{FrozenModule, GlobalsBuilder, Module},
-    eval,
-    values::{
-        UnpackValue,
-        typing::{FrozenStarlarkCallable, StarlarkCallable, StarlarkCallableParamSpec},
-    },
-};
-use std::{
-    collections::HashMap,
-    path::{Path, PathBuf},
-};
-
-use crate::eval::{
-    Config, Metadata, TarballSource, UnpackCloned, eval_files, recipe_globals, types_globals,
-};
-
-pub struct SourceRecipe {
-    pub name: String,
-    pub source: Box<dyn Source>,
-}
-
-pub trait Source {}
-
-pub struct ToolRecipe {
-    pub name: String,
-    pub sources: Vec<String>,
-    pub tools_wanted: Vec<String>,
-    pub pkgs_wanted: Vec<String>,
-}
-
-#[derive(Debug)]
-pub struct PackageRecipe {
-    pub name: String,
-    pub meta: Option<Metadata>,
-    pub version: String,
-    pub revision: u32,
-    pub sources: Vec<String>,
-    pub tools_wanted: Vec<String>,
-    pub pkgs_wanted: Vec<String>,
-    pub module: FrozenModule,
-    pub configure: Option<FrozenStarlarkCallable>,
-    pub build: Option<FrozenStarlarkCallable>,
-    pub install: Option<FrozenStarlarkCallable>,
-}
-
-pub struct RecipeSet<'a> {
-    sources: HashMap<String, SourceRecipe>,
-    tools: HashMap<String, ToolRecipe>,
-    pub packages: HashMap<String, PackageRecipe>,
-    config: &'a Config,
-}
-
-impl<'a> RecipeSet<'a> {
-    fn add_source(&mut self, name: &str, recipe: SourceRecipe) -> anyhow::Result<()> {
-        if self.sources.insert(name.to_string(), recipe).is_some() {
-            anyhow::bail!("source '{name}' already exists");
-        }
-        Ok(())
-    }
-
-    fn add_tool(&mut self, name: &str, recipe: ToolRecipe) -> anyhow::Result<()> {
-        if self.tools.insert(name.to_string(), recipe).is_some() {
-            anyhow::bail!("tool '{name}' already exists");
-        }
-        Ok(())
-    }
-
-    fn add_package(&mut self, name: &str, recipe: PackageRecipe) -> anyhow::Result<()> {
-        if self.packages.insert(name.to_string(), recipe).is_some() {
-            anyhow::bail!("package '{name}' already exists");
-        }
-        Ok(())
-    }
-
-    fn load_tool_recipe(&mut self, name: &str, path: &Path) -> anyhow::Result<()> {
-        Ok(())
-    }
-
-    fn load_package_recipe(&mut self, name: &str, path: &Path) -> anyhow::Result<()> {
-        let module = eval_files(
-            &[path],
-            &GlobalsBuilder::standard()
-                .with(types_globals)
-                .with(recipe_globals)
-                .build(),
-            None,
-            Some(self.config),
-            None,
-        )?;
-
-        let module = module.freeze().map_err(|err| anyhow::anyhow!("{err:?}"))?;
-
-        let version: String = get_value(&module, "version")?;
-        let revision: u32 = get_value_option(&module, "revision")?.unwrap_or(1);
-        let metadata: Option<Metadata> = get_value_option(&module, "metadata")?;
-        let source: TarballSource = get_value(&module, "source")?;
-
-        let configure = get_frozen_callable(&module, "configure")?;
-        let build = get_frozen_callable(&module, "build")?;
-        let install = get_frozen_callable(&module, "install")?;
-
-        self.add_source(
-            name,
-            SourceRecipe {
-                name: name.to_string(),
-                source: Box::new(source),
-            },
-        )?;
-
-        self.add_package(
-            name,
-            PackageRecipe {
-                name: name.to_string(),
-                meta: metadata,
-                version,
-                revision,
-                sources: vec![name.to_string()],
-                tools_wanted: vec![],
-                pkgs_wanted: vec![],
-                module,
-                configure,
-                build,
-                install,
-            },
-        )
-    }
-
-    pub fn new(config: &'a Config) -> Self {
-        Self {
-            sources: HashMap::new(),
-            tools: HashMap::new(),
-            packages: HashMap::new(),
-            config,
-        }
-    }
-
-    pub fn load_recipes(
-        &mut self,
-        recipes_dir: &Path,
-        host_recipes_dir: &Path,
-    ) -> anyhow::Result<()> {
-        for (dir, tool_recipe) in [(recipes_dir, false), (host_recipes_dir, true)] {
-            for entry in std::fs::read_dir(dir)? {
-                let entry = entry.context("reading directory entry")?;
-
-                if let Some((name, path)) = get_recipe_name_and_patch(&entry)? {
-                    if tool_recipe {
-                        self.load_tool_recipe(&name, &path)?;
-                    } else {
-                        self.load_package_recipe(&name, &path)?;
-                    }
-                }
-            }
-        }
-
-        Ok(())
-    }
-
-    pub fn source(&self, name: &str) -> Option<&SourceRecipe> {
-        self.sources.get(name)
-    }
-
-    pub fn tool(&self, name: &str) -> Option<&ToolRecipe> {
-        self.tools.get(name)
-    }
-
-    pub fn package(&self, name: &str) -> Option<&PackageRecipe> {
-        self.packages.get(name)
-    }
-}
-
-fn get_recipe_name_and_patch(
-    entry: &std::fs::DirEntry,
-) -> anyhow::Result<Option<(String, PathBuf)>> {
-    let file_type = entry.file_type()?;
-    let path = entry.path();
-
-    if file_type.is_dir() {
-        let recipe_path = path.join("recipe.star");
-
-        if recipe_path.exists() {
-            return Ok(Some((
-                entry.file_name().to_str().unwrap_or("").to_string(),
-                recipe_path,
-            )));
-        }
-    } else {
-        let name = path.file_stem().unwrap().to_str().unwrap_or("").to_string();
-        let extension = path
-            .extension()
-            .ok_or(anyhow::anyhow!("File did not have an extension"))?;
-
-        if extension == "star" {
-            return Ok(Some((name, path)));
-        }
-    }
-
-    Ok(None)
-}
-
-fn get_value_option<T: UnpackCloned>(
-    module: &FrozenModule,
-    name: &str,
-) -> anyhow::Result<Option<T>> {
-    module
-        .get_option(name)?
-        .map(|value| {
-            T::unpack_cloned(value.value()).ok_or_else(|| {
-                anyhow::anyhow!(
-                    "`{name}` should be of type `{}` but got `{}`",
-                    T::starlark_type_repr(),
-                    value.value().get_type()
-                )
-            })
-        })
-        .transpose()
-}
-
-fn get_value<T: UnpackCloned>(module: &FrozenModule, name: &str) -> anyhow::Result<T> {
-    let value = module
-        .get_option(name)?
-        .ok_or_else(|| anyhow::anyhow!("`{name}` is required"))?;
-
-    T::unpack_cloned(value.value()).ok_or_else(|| {
-        anyhow::anyhow!(
-            "`{name}` should be of type `{}` but got `{}`",
-            T::starlark_type_repr(),
-            value.value().get_type()
-        )
-    })
-}
-
-fn get_frozen_callable<P: StarlarkCallableParamSpec>(
-    module: &FrozenModule,
-    name: &str,
-) -> anyhow::Result<Option<FrozenStarlarkCallable<P>>> {
-    let Some(value) = module.get_option(name)? else {
-        return Ok(None);
-    };
-
-    let callable = StarlarkCallable::unpack_value(value.value())
-        .map_err(|err| anyhow::anyhow!("{err}"))?
-        .ok_or_else(|| {
-            anyhow::anyhow!(
-                "`{name}` should be callable but got `{}`",
-                value.value().get_type()
-            )
-        })?;
-
-    callable
-        .unpack_frozen()
-        .ok_or_else(|| anyhow::anyhow!("`{name}` was callable but not frozen"))
-        .map(Some)
-}

src/recipe/metadata.rs

@@ -0,0 +1,54 @@
+use allocative::Allocative;
+use starlark::values::StarlarkValue;
+use starlark_derive::{NoSerialize, ProvidesStaticType, starlark_value};
+
+#[derive(Debug, Clone, Allocative, ProvidesStaticType, NoSerialize)]
+pub struct Metadata {
+    maintainer: Option<String>,
+    description: Option<String>,
+    license: Option<String>,
+    website: Option<String>,
+}
+
+impl std::fmt::Display for Metadata {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "metadata")
+    }
+}
+
+starlark::starlark_simple_value!(Metadata);
+
+#[starlark_value(type = "metadata")]
+impl<'v> StarlarkValue<'v> for Metadata {}
+
+impl Metadata {
+    pub fn new(
+        maintainer: Option<String>,
+        description: Option<String>,
+        license: Option<String>,
+        website: Option<String>,
+    ) -> Self {
+        Self {
+            maintainer,
+            description,
+            license,
+            website,
+        }
+    }
+
+    pub fn maintainer(&self) -> Option<&str> {
+        self.maintainer.as_deref()
+    }
+
+    pub fn description(&self) -> Option<&str> {
+        self.description.as_deref()
+    }
+
+    pub fn license(&self) -> Option<&str> {
+        self.license.as_deref()
+    }
+
+    pub fn website(&self) -> Option<&str> {
+        self.website.as_deref()
+    }
+}

src/recipe/mod.rs

@@ -0,0 +1,532 @@
+mod metadata;
+mod source;
+mod subpackage;
+
+use anyhow::{Context, bail};
+use starlark::{
+    environment::{FrozenModule, Module},
+    values::{
+        OwnedFrozenValue, UnpackValue, ValueLike, dict::DictRef, list::ListRef,
+        typing::StarlarkCallable,
+    },
+};
+use std::{
+    collections::HashMap,
+    fmt,
+    path::{Path, PathBuf},
+};
+use walkdir::WalkDir;
+
+use crate::{
+    eval::{self, ExtractError},
+    options::Options,
+};
+
+pub use metadata::Metadata;
+pub use source::{GitSource, Source, TarballSource};
+pub use subpackage::Subpackage;
+
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum RecipeKind {
+    Package,
+    HostPackage,
+}
+
+impl RecipeKind {
+    pub fn key(self, name: &str) -> String {
+        match self {
+            Self::Package => name.to_string(),
+            Self::HostPackage => format!("host:{name}"),
+        }
+    }
+
+    pub fn slug(self, name: &str) -> String {
+        self.key(name).replace(':', "-")
+    }
+}
+
+#[derive(Debug)]
+pub enum Sources {
+    Single(source::Source),
+    Multiple(HashMap<String, source::Source>),
+}
+
+impl Sources {
+    pub fn entries(&self) -> Vec<(Option<&str>, &source::Source)> {
+        match self {
+            Self::Single(source) => vec![(None, source)],
+            Self::Multiple(sources) => {
+                let mut entries = sources
+                    .iter()
+                    .map(|(name, source)| (Some(name.as_str()), source))
+                    .collect::<Vec<_>>();
+                entries.sort_by_key(|(name, _)| *name);
+                entries
+            }
+        }
+    }
+}
+
+pub struct Recipe {
+    /// Recipe name without namespace prefix.
+    name: String,
+    /// Path to the recipe's .star file.
+    path: PathBuf,
+    /// What kind of a recipe is that?
+    kind: RecipeKind,
+    /// Version shared by every package output of this recipe.
+    version: String,
+    /// Revision shared by every package output of this recipe.
+    revision: i32,
+    /// List of sources required to build this recipe.
+    sources: Sources,
+    /// All packages produced by this recipe.
+    /// This is empty for host recipes.
+    outputs: Vec<OutputPackage>,
+    /// Host packages requires for this recipe.
+    host_deps: Vec<String>,
+    /// Packages installed to the system root during build of the recipe, but
+    /// not listed as part of the `apk` dependencies.
+    build_deps: Vec<String>,
+    /// Packages installed to the system root during build of the recipe AND
+    /// listed as part of the `apk` dependencies.
+    deps: Vec<String>,
+    /// Packages NOT installed to the system root during build, only listed
+    /// as part of the `apk` dependencies.
+    run_deps: Vec<String>,
+    /// Starlark phase functions defined by the recipe.
+    phases: RecipePhases,
+}
+
+impl fmt::Debug for Recipe {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Recipe")
+            .field("path", &self.path)
+            .field("kind", &self.kind)
+            .field("version", &self.version)
+            .field("revision", &self.revision)
+            .field("sources", &self.sources)
+            .field("outputs", &self.outputs)
+            .field("host_deps", &self.host_deps)
+            .field("build_deps", &self.build_deps)
+            .field("deps", &self.deps)
+            .field("run_deps", &self.run_deps)
+            .field("phases", &self.phases)
+            .finish()
+    }
+}
+
+impl Recipe {
+    pub fn load(
+        path: &Path,
+        name: &str,
+        kind: RecipeKind,
+        options: &Options,
+        lib: Option<&FrozenModule>,
+    ) -> anyhow::Result<Self> {
+        let module = eval::eval_file(path, Some(options), lib)
+            .with_context(|| format!("evaluating recipe {}", path.display()))?;
+
+        let version = eval::extract_string(&module, "version")
+            .map_err(|e| anyhow::anyhow!("field `version`: {e}"))?;
+
+        let revision = match eval::extract_i32(&module, "revision") {
+            Ok(v) => v,
+            Err(ExtractError::NotFound) => 1,
+            Err(e) => bail!("field `revision`: {e}"),
+        };
+
+        let metadata = match module.get("metadata") {
+            None => Metadata::new(None, None, None, None),
+            Some(value) => value
+                .downcast_ref::<Metadata>()
+                .ok_or_else(|| anyhow::anyhow!("field `metadata`: expected a metadata value"))?
+                .clone(),
+        };
+
+        let source_value = module.get("source");
+        let sources_value = module.get("sources");
+        let sources = match (source_value, sources_value) {
+            (None, None) => bail!("recipe must define either `source` or `sources`"),
+            (Some(_), Some(_)) => {
+                bail!("recipe must define exactly one of `source` or `sources`, not both")
+            }
+            (Some(value), None) => {
+                let source = value
+                    .downcast_ref::<Source>()
+                    .ok_or_else(|| anyhow::anyhow!("field `source`: expected a source value"))?
+                    .clone();
+                Sources::Single(source)
+            }
+            (None, Some(value)) => {
+                let dict = DictRef::from_value(value).ok_or_else(|| {
+                    anyhow::anyhow!("field `sources`: expected a dict of name -> source")
+                })?;
+                if dict.iter().len() == 0 {
+                    bail!("field `sources`: must contain at least one entry");
+                }
+                let mut map: HashMap<String, source::Source> = HashMap::new();
+                for (key, value) in dict.iter() {
+                    let key_str = key
+                        .unpack_str()
+                        .ok_or_else(|| anyhow::anyhow!("field `sources`: keys must be strings"))?;
+                    if !is_valid_source_name(key_str) {
+                        bail!(
+                            "field `sources`: invalid source name `{key_str}` (allowed: letters, digits, `-`, `_`; must start with a letter or digit)"
+                        );
+                    }
+                    let source = value.downcast_ref::<Source>().ok_or_else(|| {
+                        anyhow::anyhow!("field `sources`: entry `{key_str}` is not a source value")
+                    })?;
+                    if map.insert(key_str.to_owned(), source.clone()).is_some() {
+                        bail!("field `sources`: duplicate key `{key_str}`");
+                    }
+                }
+                Sources::Multiple(map)
+            }
+        };
+
+        let host_deps = optional_string_list(&module, "host_deps")?;
+        let build_deps = optional_string_list(&module, "build_deps")?;
+        let deps = optional_string_list(&module, "deps")?;
+        let run_deps = optional_string_list(&module, "run_deps")?;
+
+        let recipe_key = kind.key(name);
+        let outputs = match kind {
+            RecipeKind::Package => {
+                let mut outputs = vec![OutputPackage {
+                    recipe: recipe_key.clone(),
+                    name: name.to_owned(),
+                    metadata: metadata.clone(),
+                }];
+                if let Some(value) = module.get("subpackages") {
+                    let list = ListRef::from_value(value)
+                        .ok_or_else(|| anyhow::anyhow!("field `subpackages`: expected a list"))?;
+                    for item in list.iter() {
+                        let sub = item.downcast_ref::<Subpackage>().ok_or_else(|| {
+                            anyhow::anyhow!(
+                                "field `subpackages`: each entry must be a subpackage value"
+                            )
+                        })?;
+                        outputs.push(OutputPackage {
+                            recipe: recipe_key.clone(),
+                            name: sub.name().to_owned(),
+                            metadata: sub.metadata().clone(),
+                        });
+                    }
+                }
+                outputs
+            }
+            RecipeKind::HostPackage => {
+                if module.get("subpackages").is_some() {
+                    bail!("host recipes cannot declare `subpackages`");
+                }
+                Vec::new()
+            }
+        };
+
+        let module = module
+            .freeze()
+            .map_err(|err| anyhow::anyhow!("freezing recipe module {}: {err:?}", path.display()))?;
+        let phases = RecipePhases::load(&module)?;
+
+        Ok(Recipe {
+            name: name.to_owned(),
+            path: path.to_path_buf(),
+            kind,
+            version,
+            revision,
+            sources,
+            outputs,
+            host_deps,
+            build_deps,
+            deps,
+            run_deps,
+            phases,
+        })
+    }
+
+    pub fn phases(&self) -> &RecipePhases {
+        &self.phases
+    }
+
+    pub fn key(&self) -> String {
+        self.kind.key(&self.name)
+    }
+
+    pub fn slug(&self) -> String {
+        self.kind.slug(&self.name)
+    }
+
+    pub fn dir(&self) -> &Path {
+        self.path.parent().unwrap_or_else(|| Path::new("."))
+    }
+
+    pub fn path(&self) -> &Path {
+        &self.path
+    }
+
+    pub fn kind(&self) -> RecipeKind {
+        self.kind
+    }
+
+    pub fn version(&self) -> &str {
+        &self.version
+    }
+
+    pub fn revision(&self) -> i32 {
+        self.revision
+    }
+
+    pub fn sources(&self) -> &Sources {
+        &self.sources
+    }
+
+    pub fn outputs(&self) -> &[OutputPackage] {
+        &self.outputs
+    }
+
+    pub fn host_deps(&self) -> &[String] {
+        &self.host_deps
+    }
+
+    pub fn build_deps(&self) -> &[String] {
+        &self.build_deps
+    }
+
+    pub fn deps(&self) -> &[String] {
+        &self.deps
+    }
+
+    pub fn run_deps(&self) -> &[String] {
+        &self.run_deps
+    }
+}
+
+fn optional_string_list(module: &Module, key: &str) -> anyhow::Result<Vec<String>> {
+    match eval::extract_string_list(module, key) {
+        Ok(v) => Ok(v),
+        Err(ExtractError::NotFound) => Ok(Vec::new()),
+        Err(e) => Err(anyhow::anyhow!("field `{key}`: {e}")),
+    }
+}
+
+fn is_valid_source_name(name: &str) -> bool {
+    let mut chars = name.chars();
+    let Some(first) = chars.next() else {
+        return false;
+    };
+    if !first.is_ascii_alphanumeric() {
+        return false;
+    }
+    chars.all(|c| c.is_ascii_alphanumeric() || c == '-' || c == '_')
+}
+
+pub struct RecipePhases {
+    configure: Option<OwnedFrozenValue>,
+    build: OwnedFrozenValue,
+    install: OwnedFrozenValue,
+}
+
+impl fmt::Debug for RecipePhases {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("RecipePhases")
+            .field("configure", &self.configure.is_some())
+            .field("build", &true)
+            .field("install", &true)
+            .finish()
+    }
+}
+
+impl RecipePhases {
+    fn load(module: &FrozenModule) -> anyhow::Result<Self> {
+        Ok(Self {
+            configure: optional_phase_function(module, "configure")?,
+            build: required_phase_function(module, "build")?,
+            install: required_phase_function(module, "install")?,
+        })
+    }
+
+    pub fn configure(&self) -> Option<&OwnedFrozenValue> {
+        self.configure.as_ref()
+    }
+
+    pub fn build(&self) -> &OwnedFrozenValue {
+        &self.build
+    }
+
+    pub fn install(&self) -> &OwnedFrozenValue {
+        &self.install
+    }
+}
+
+fn optional_phase_function(
+    module: &FrozenModule,
+    name: &str,
+) -> anyhow::Result<Option<OwnedFrozenValue>> {
+    let Some(value) = module
+        .get_option(name)
+        .with_context(|| format!("field `{name}`"))?
+    else {
+        return Ok(None);
+    };
+
+    validate_phase_function(name, &value)?;
+    Ok(Some(value))
+}
+
+fn required_phase_function(module: &FrozenModule, name: &str) -> anyhow::Result<OwnedFrozenValue> {
+    let value = module
+        .get_option(name)
+        .with_context(|| format!("field `{name}`"))?
+        .ok_or_else(|| anyhow::anyhow!("field `{name}`: missing"))?;
+
+    validate_phase_function(name, &value)?;
+    Ok(value)
+}
+
+fn validate_phase_function(name: &str, value: &OwnedFrozenValue) -> anyhow::Result<()> {
+    let callable: Option<StarlarkCallable<'_>> = StarlarkCallable::unpack_value_opt(value.value());
+    if callable.is_none() {
+        bail!("field `{name}`: expected a callable value");
+    }
+    Ok(())
+}
+
+#[derive(Clone, Debug)]
+pub struct OutputPackage {
+    /// Canonical key of the owning recipe.
+    recipe: String,
+    /// Name of the output package.
+    name: String,
+    /// Metadata attached to the output package.
+    metadata: Metadata,
+}
+
+impl OutputPackage {
+    pub fn key(&self) -> String {
+        self.name.clone()
+    }
+
+    pub fn recipe(&self) -> &str {
+        &self.recipe
+    }
+
+    pub fn name(&self) -> &str {
+        &self.name
+    }
+
+    pub fn metadata(&self) -> &Metadata {
+        &self.metadata
+    }
+}
+
+#[derive(Debug)]
+pub struct RecipeSet {
+    recipes: HashMap<String, Recipe>,
+    outputs: HashMap<String, OutputPackage>,
+}
+
+impl RecipeSet {
+    pub fn load(
+        root_path: &Path,
+        options: &Options,
+        lib: Option<&FrozenModule>,
+    ) -> anyhow::Result<Self> {
+        let mut recipes = HashMap::new();
+        let mut outputs = HashMap::new();
+
+        for (path, kind) in [
+            ("recipes", RecipeKind::Package),
+            ("host-recipes", RecipeKind::HostPackage),
+        ] {
+            let recipes_dir = root_path.join(path);
+
+            if !recipes_dir.exists() {
+                continue;
+            }
+
+            for (name, path) in discover_recipes(&recipes_dir)? {
+                let recipe = Recipe::load(&path, &name, kind, options, lib)
+                    .with_context(|| format!("loading recipe `{name}`"))?;
+                let key = kind.key(&name);
+
+                if recipes.insert(key.clone(), recipe).is_some() {
+                    bail!("duplicate recipe `{key}`");
+                }
+            }
+        }
+
+        for recipe in recipes.values() {
+            for output in &recipe.outputs {
+                let key = recipe.kind.key(&output.name);
+
+                if outputs.insert(key.clone(), output.clone()).is_some() {
+                    bail!("duplicate package output `{key}`");
+                }
+            }
+        }
+
+        Ok(Self { recipes, outputs })
+    }
+
+    pub fn recipe(&self, key: &str) -> anyhow::Result<&Recipe> {
+        self.recipes
+            .get(key)
+            .ok_or_else(|| anyhow::anyhow!("unknown recipe `{key}`"))
+    }
+
+    pub fn output(&self, key: &str) -> anyhow::Result<&OutputPackage> {
+        self.outputs
+            .get(key)
+            .ok_or_else(|| anyhow::anyhow!("unknown output package `{key}`"))
+    }
+}
+
+/// Find all recipe `.star` files under `dir`, returning a map of recipe name
+/// to its `.star` file. Intermediate directories act as categories and are
+/// not themselves recipes. Within any subtree, a recipe takes either form:
+///   - `.../<name>.star`           — name is the file stem
+///   - `.../<name>/recipe.star`    — name is the parent directory
+fn discover_recipes(dir: &Path) -> anyhow::Result<HashMap<String, PathBuf>> {
+    let mut recipes: HashMap<String, PathBuf> = HashMap::new();
+
+    let walker = WalkDir::new(dir).follow_links(false);
+    for entry in walker {
+        let entry =
+            entry.with_context(|| format!("walking recipes directory {}", dir.display()))?;
+        if !entry.file_type().is_file() {
+            continue;
+        }
+
+        let path = entry.path();
+        let Some(file_name) = path.file_name().and_then(|n| n.to_str()) else {
+            continue;
+        };
+
+        let name = if file_name == "recipe.star" {
+            let Some(parent_name) = path
+                .parent()
+                .and_then(|p| p.file_name())
+                .and_then(|n| n.to_str())
+            else {
+                continue;
+            };
+            parent_name.to_owned()
+        } else if let Some(stem) = file_name.strip_suffix(".star") {
+            stem.to_owned()
+        } else {
+            continue;
+        };
+
+        if let Some(existing) = recipes.insert(name.clone(), path.to_path_buf()) {
+            bail!(
+                "recipe `{name}` is defined twice: {} and {}",
+                existing.display(),
+                recipes[&name].display(),
+            );
+        }
+    }
+
+    Ok(recipes)
+}

src/recipe/source.rs

@@ -0,0 +1,111 @@
+use allocative::Allocative;
+use starlark::values::StarlarkValue;
+use starlark_derive::{NoSerialize, ProvidesStaticType, starlark_value};
+
+#[derive(Debug, Clone, Allocative, ProvidesStaticType, NoSerialize)]
+pub struct TarballSource {
+    url: String,
+    sha256: String,
+    strip_components: u32,
+}
+
+impl std::fmt::Display for TarballSource {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "tarball_source")
+    }
+}
+
+starlark::starlark_simple_value!(TarballSource);
+
+#[starlark_value(type = "tarball_source")]
+impl<'v> StarlarkValue<'v> for TarballSource {}
+
+impl TarballSource {
+    pub fn new(url: String, sha256: String, strip_components: u32) -> Self {
+        Self {
+            url,
+            sha256,
+            strip_components,
+        }
+    }
+
+    pub fn url(&self) -> &str {
+        &self.url
+    }
+
+    pub fn sha256(&self) -> &str {
+        &self.sha256
+    }
+
+    pub fn strip_components(&self) -> u32 {
+        self.strip_components
+    }
+}
+
+#[derive(Debug, Clone, Allocative, ProvidesStaticType, NoSerialize)]
+pub struct GitSource {
+    url: String,
+    commit: String,
+}
+
+impl std::fmt::Display for GitSource {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "git_source")
+    }
+}
+
+starlark::starlark_simple_value!(GitSource);
+
+#[starlark_value(type = "git_source")]
+impl<'v> StarlarkValue<'v> for GitSource {}
+
+impl GitSource {
+    pub fn new(url: String, commit: String) -> Self {
+        Self { url, commit }
+    }
+
+    pub fn url(&self) -> &str {
+        &self.url
+    }
+
+    pub fn commit(&self) -> &str {
+        &self.commit
+    }
+}
+
+#[derive(Debug, Clone, Allocative, ProvidesStaticType, NoSerialize)]
+pub enum Source {
+    Tarball(TarballSource),
+    Git(GitSource),
+}
+
+impl std::fmt::Display for Source {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "source")
+    }
+}
+
+starlark::starlark_simple_value!(Source);
+
+#[starlark_value(type = "source")]
+impl<'v> StarlarkValue<'v> for Source {}
+
+impl Source {
+    pub fn url(&self) -> &str {
+        match self {
+            Self::Tarball(source) => source.url(),
+            Self::Git(source) => source.url(),
+        }
+    }
+
+    pub fn cache_key(&self) -> &str {
+        match self {
+            Self::Tarball(source) => source.sha256(),
+            Self::Git(source) => source.commit(),
+        }
+    }
+
+    pub fn is_unknown_cache_key(&self) -> bool {
+        matches!(self.cache_key(), "?" | "???")
+    }
+}

src/recipe/subpackage.rs

@@ -0,0 +1,36 @@
+use allocative::Allocative;
+use starlark::values::StarlarkValue;
+use starlark_derive::{NoSerialize, ProvidesStaticType, starlark_value};
+
+use crate::recipe::Metadata;
+
+#[derive(Debug, Clone, Allocative, ProvidesStaticType, NoSerialize)]
+pub struct Subpackage {
+    name: String,
+    metadata: Metadata,
+}
+
+impl Subpackage {
+    pub fn new(name: String, metadata: Metadata) -> Self {
+        Self { name, metadata }
+    }
+
+    pub fn name(&self) -> &str {
+        &self.name
+    }
+
+    pub fn metadata(&self) -> &Metadata {
+        &self.metadata
+    }
+}
+
+impl std::fmt::Display for Subpackage {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "subpackage")
+    }
+}
+
+starlark::starlark_simple_value!(Subpackage);
+
+#[starlark_value(type = "subpackage")]
+impl<'v> StarlarkValue<'v> for Subpackage {}