Run nix build.

example_config.toml

@@ -1,4 +1,4 @@
-# work_directory = "/home/nixworker/persist/nix_builder"
+# repo_directory = "/home/nixworker/persist/nix_builder"
 
 [[targets]]
   name = "odo"

src/command/build/runner.rs

@@ -6,6 +6,7 @@ use crate::fs_util::assert_directory;
 use crate::fs_util::is_git_repo;
 use crate::git_util::git_force_into_state;
 use crate::git_util::git_init_at_rev;
+use crate::nix_util::nixos_build_target;
 
 pub(crate) async fn run_build(args: BuildArgs) -> Result<(), CustomError> {
     println!("{:?}", args);
@@ -23,6 +24,7 @@ pub(crate) async fn run_build(args: BuildArgs) -> Result<(), CustomError> {
         };
 
         prepare_flake_repo(&config, target_config).await?;
+        build_target(&config, target_config).await?;
     }
 
     Ok(())
@@ -32,17 +34,17 @@ async fn prepare_flake_repo(
     config_root: &Config,
     target_config: &TargetConfig,
 ) -> Result<(), CustomError> {
-    let flake_directory = target_config.get_flake_directory(config_root)?;
+    let repo_directory = target_config.get_repo_directory(config_root)?;
     assert_directory!(
-        &flake_directory,
-        "Creating flake directory {}",
-        (&flake_directory).to_string_lossy()
+        &repo_directory,
+        "Creating repo directory {}",
+        (&repo_directory).to_string_lossy()
     );
 
-    if is_git_repo(&flake_directory).await? {
+    if is_git_repo(&repo_directory).await? {
         // Clean up the existing clone
         git_force_into_state(
-            &flake_directory,
+            &repo_directory,
             target_config.get_branch()?,
             "origin",
             target_config.get_repo()?,
@@ -51,7 +53,7 @@ async fn prepare_flake_repo(
         .await?;
     } else {
         git_init_at_rev(
-            &flake_directory,
+            &repo_directory,
             target_config.get_branch()?,
             target_config.get_repo()?,
             target_config.get_revision()?,
@@ -60,3 +62,20 @@ async fn prepare_flake_repo(
     }
     Ok(())
 }
+
+async fn build_target(
+    config_root: &Config,
+    target_config: &TargetConfig,
+) -> Result<(), CustomError> {
+    let flake_directory = target_config.get_flake_directory(config_root)?;
+    let build_directory = target_config.get_build_directory(config_root)?;
+    assert_directory!(
+        &build_directory,
+        "Creating build directory {}",
+        (&build_directory).to_string_lossy()
+    );
+
+    nixos_build_target(build_directory, flake_directory, target_config.get_attr()?).await?;
+
+    Ok(())
+}

src/config/root.rs

@@ -15,7 +15,7 @@ use super::TargetConfig;
 pub(crate) struct Config {
     #[serde(skip)]
     config_path: Option<PathBuf>,
-    work_directory: Option<PathBuf>,
+    output_directory: Option<PathBuf>,
     targets: Vec<TargetConfig>,
 }
 
@@ -63,9 +63,9 @@ impl Config {
         Ok(target_config)
     }
 
-    pub(crate) fn get_work_directory(&self) -> Result<Cow<'_, Path>, CustomError> {
-        let maybe_work_directory = self.work_directory.as_deref().map(Cow::Borrowed);
-        if let Some(work_dir) = maybe_work_directory {
+    pub(crate) fn get_output_directory(&self) -> Result<Cow<'_, Path>, CustomError> {
+        let maybe_repo_directory = self.output_directory.as_deref().map(Cow::Borrowed);
+        if let Some(work_dir) = maybe_repo_directory {
             return Ok(work_dir);
         }
         let current_dir: PathBuf = std::env::current_dir()?;

src/config/target.rs

@@ -24,7 +24,7 @@ pub(crate) struct TargetConfig {
     pub(super) path: Option<String>,
 
     #[serde(default)]
-    pub(super) attr: Option<String>,
+    pub(super) attr: String,
 
     #[serde(default)]
     pub(super) update: Option<bool>,
@@ -34,26 +34,44 @@ pub(crate) struct TargetConfig {
 }
 
 impl TargetConfig {
+    /// The root directory for this specific build target.
     pub(crate) fn get_target_directory<'target, 'root>(
         &'target self,
         config_root: &'root Config,
     ) -> Result<Cow<'target, Path>, CustomError> {
-        let work_directory = config_root.get_work_directory()?;
-        Ok(Cow::Owned(work_directory.join(&self.name)))
+        let repo_directory = config_root.get_output_directory()?;
+        Ok(Cow::Owned(repo_directory.join(&self.name)))
     }
 
-    pub(crate) fn get_flake_directory<'target, 'root>(
+    /// The root of the checkout of the git repository.
+    pub(crate) fn get_repo_directory<'target, 'root>(
         &'target self,
         config_root: &'root Config,
     ) -> Result<Cow<'target, Path>, CustomError> {
         let target_directory = self.get_target_directory(config_root)?;
-        Ok(Cow::Owned(target_directory.join("flake")))
+        Ok(Cow::Owned(target_directory.join("repo")))
     }
 
+    /// The directory that contains flake.nix.
+    pub(crate) fn get_flake_directory<'target, 'root>(
+        &'target self,
+        config_root: &'root Config,
+    ) -> Result<Cow<'target, Path>, CustomError> {
+        let repo_directory = self.get_repo_directory(config_root)?;
+        let subpath = self.path.as_deref();
+        if let Some(subpath) = subpath {
+            Ok(Cow::Owned(repo_directory.join(subpath)))
+        } else {
+            Ok(repo_directory)
+        }
+    }
+
+    /// The URL to the upstream git repository.
     pub(crate) fn get_repo(&'_ self) -> Result<&String, CustomError> {
         Ok(&self.repo)
     }
 
+    /// The git branch name to track.
     pub(crate) fn get_branch(&'_ self) -> Result<Cow<'_, str>, CustomError> {
         if let Some(b) = &self.branch {
             Ok(Cow::Borrowed(b))
@@ -62,7 +80,22 @@ impl TargetConfig {
         }
     }
 
+    /// If we want to pin to a specific revision, this is the reference to that commit.
     pub(crate) fn get_revision(&self) -> Result<&Option<String>, CustomError> {
         Ok(&self.revision)
     }
+
+    /// The folder where nixos-rebuild is invoked and the outputs are linked.
+    pub(crate) fn get_build_directory<'target, 'root>(
+        &'target self,
+        config_root: &'root Config,
+    ) -> Result<Cow<'target, Path>, CustomError> {
+        let target_directory = self.get_target_directory(config_root)?;
+        Ok(Cow::Owned(target_directory.join("build")))
+    }
+
+    /// The flake output attribute to build (the part after '#' in the build command).
+    pub(crate) fn get_attr(&'_ self) -> Result<&String, CustomError> {
+        Ok(&self.attr)
+    }
 }

src/main.rs

@@ -16,6 +16,7 @@ mod error;
 mod fs_util;
 mod git_util;
 mod init_tracing;
+mod nix_util;
 
 fn main() -> Result<ExitCode, CustomError> {
     let rt = tokio::runtime::Runtime::new()?;

src/nix_util/high_level.rs

@@ -0,0 +1,58 @@
+use std::ffi::OsStr;
+use std::ffi::OsString;
+use std::path::Path;
+
+use tokio::process::Command;
+
+use crate::error::CustomError;
+
+pub(crate) async fn nixos_build_target<B, F, A>(
+    build_path: B,
+    flake_path: F,
+    attr: A,
+) -> Result<(), CustomError>
+where
+    B: AsRef<Path>,
+    F: AsRef<Path>,
+    A: AsRef<str>,
+{
+    let reference = {
+        let path = AsRef::<OsStr>::as_ref(flake_path.as_ref());
+        let attr = attr.as_ref();
+        let mut reference = OsString::with_capacity(path.len() + attr.len() + 1);
+        reference.push(path);
+        reference.push("#");
+        reference.push(attr);
+        reference
+    };
+
+    // nixos-rebuild build --show-trace --sudo --max-jobs "$JOBS" --flake "$DIR/../../#odo" --log-format internal-json -v "${@}"
+    let mut command = Command::new("nixos-rebuild");
+    command.current_dir(build_path);
+    command.args(&[
+        "build",
+        "--show-trace",
+        "--sudo",
+        "--max-jobs",
+        "1",
+        "--log-format",
+        "internal-json",
+        "-v",
+    ]);
+    command.arg("--flake");
+    command.arg(reference);
+    command.kill_on_drop(true);
+
+    let mut child = command.spawn()?;
+    let status = child.wait().await?;
+    if !status.success() {
+        return Err("Nixos rebuild failed.".into());
+    }
+
+    // tokio::spawn(async move {
+    //     let status = child.wait().await.expect("mpv encountered an error");
+    //     println!("mpv status was: {}", status);
+    // });
+
+    Ok(())
+}

src/nix_util/mod.rs

@@ -0,0 +1,2 @@
+mod high_level;
+pub(crate) use high_level::*;