daemon: Add config loading

Cargo.lock

@@ -283,6 +283,20 @@ dependencies = [
  "crossbeam-utils",
 ]
 
+[[package]]
+name = "config"
+version = "0.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7328b20597b53c2454f0b1919720c25c7339051c02b72b7e05409e00b14132be"
+dependencies = [
+ "async-trait",
+ "lazy_static",
+ "nom",
+ "pathdiff",
+ "serde",
+ "toml",
+]
+
 [[package]]
 name = "cpufeatures"
 version = "0.2.12"
@@ -591,6 +605,12 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "minimal-lexical"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
+
 [[package]]
 name = "miniz_oxide"
 version = "0.7.2"
@@ -624,6 +644,16 @@ dependencies = [
  "memoffset",
 ]
 
+[[package]]
+name = "nom"
+version = "7.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d273983c5a657a70a3e8f2a01329822f3b8c8172b73826411a55751e404a0a4a"
+dependencies = [
+ "memchr",
+ "minimal-lexical",
+]
+
 [[package]]
 name = "num_cpus"
 version = "1.16.0"
@@ -665,6 +695,12 @@ version = "2.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bb813b8af86854136c6922af0598d719255ecb2179515e6e7730d468f05c9cae"
 
+[[package]]
+name = "pathdiff"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8835116a5c179084a830efb3adc117ab007512b535bc1a21c991d3b32a6b44dd"
+
 [[package]]
 name = "pin-project-lite"
 version = "0.2.14"
@@ -894,7 +930,9 @@ name = "steamos-manager"
 version = "24.5.1"
 dependencies = [
  "anyhow",
+ "async-trait",
  "clap",
+ "config",
  "inotify",
  "itertools",
  "libc",

Cargo.toml

@@ -12,7 +12,9 @@ strip="symbols"
 
 [dependencies]
 anyhow = "1"
+async-trait = "0.1"
 clap = { version = "4.5", default-features = false, features = ["derive", "help", "std", "usage"] }
+config = { version = "0.14", default-features = false, features = ["async", "toml"] }
 inotify = { version = "0.10", default-features = false, features = ["stream"] }
 libc = "0.2"
 itertools = "0.12"

src/daemon/config.rs

@@ -6,12 +6,53 @@
  */
 
 use anyhow::{anyhow, Result};
+use async_trait::async_trait;
+use config::builder::AsyncState;
+use config::{AsyncSource, ConfigBuilder, ConfigError, FileFormat, Format, Map, Value};
+use std::ffi::OsStr;
+use std::fmt::Debug;
 use std::io::ErrorKind;
-use tokio::fs::{create_dir_all, read_to_string, write};
-use tracing::{error, info};
+use std::path::Path;
+use tokio::fs::{create_dir_all, read_dir, read_to_string, write};
+use tracing::{debug, error, info};
 
 use crate::daemon::DaemonContext;
 
+#[derive(Debug)]
+struct AsyncFileSource<F: Format, P: AsRef<Path> + Sized + Send + Sync> {
+    path: P,
+    format: F,
+}
+
+impl<F: Format, P: AsRef<Path> + Sized + Send + Sync + Debug> AsyncFileSource<F, P> {
+    fn from(path: P, format: F) -> AsyncFileSource<F, P> {
+        AsyncFileSource { path, format }
+    }
+}
+
+#[async_trait]
+impl<F: Format + Send + Sync + Debug, P: AsRef<Path> + Sized + Send + Sync + Debug> AsyncSource
+    for AsyncFileSource<F, P>
+{
+    async fn collect(&self) -> Result<Map<String, Value>, ConfigError> {
+        let path = self.path.as_ref();
+        let text = match read_to_string(&path).await {
+            Ok(text) => text,
+            Err(e) => {
+                if e.kind() == ErrorKind::NotFound {
+                    info!("No config file {} found", path.to_string_lossy());
+                    return Ok(Map::new());
+                }
+                return Err(ConfigError::Foreign(Box::new(e)));
+            }
+        };
+        let path = path.to_string_lossy().to_string();
+        self.format
+            .parse(Some(&path), &text)
+            .map_err(ConfigError::Foreign)
+    }
+}
+
 pub(in crate::daemon) async fn read_state<C: DaemonContext>(context: &C) -> Result<C::State> {
     let path = context.state_path()?;
     let state = match read_to_string(path).await {
@@ -39,6 +80,466 @@ pub(in crate::daemon) async fn write_state<C: DaemonContext>(context: &C) -> Res
     Ok(write(path, state.as_bytes()).await?)
 }
 
-pub(in crate::daemon) async fn read_config<C: DaemonContext>(_context: &C) -> Result<C::Config> {
-    todo!();
+pub(in crate::daemon) async fn read_config<C: DaemonContext>(context: &C) -> Result<C::Config> {
+    let builder = ConfigBuilder::<AsyncState>::default();
+    let system_config_path = context.system_config_path()?;
+    let user_config_path = context.user_config_path()?;
+
+    let builder = builder.add_async_source(AsyncFileSource::from(
+        system_config_path.join("config.toml"),
+        FileFormat::Toml,
+    ));
+    let builder = read_config_directory(builder, system_config_path.join("config.toml.d")).await?;
+
+    let builder = builder.add_async_source(AsyncFileSource::from(
+        user_config_path.join("config.toml"),
+        FileFormat::Toml,
+    ));
+    let builder = read_config_directory(builder, user_config_path.join("config.toml.d")).await?;
+    let config = builder.build().await?;
+    Ok(config.try_deserialize()?)
+}
+
+async fn read_config_directory<P: AsRef<Path> + Sync + Send>(
+    builder: ConfigBuilder<AsyncState>,
+    path: P,
+) -> Result<ConfigBuilder<AsyncState>> {
+    let mut dir = match read_dir(&path).await {
+        Ok(dir) => dir,
+        Err(e) => {
+            if e.kind() == ErrorKind::NotFound {
+                debug!(
+                    "No config fragment directory {} found",
+                    path.as_ref().to_string_lossy()
+                );
+                return Ok(builder);
+            }
+            error!("Error reading config fragment directory: {e}");
+            return Err(e.into());
+        }
+    };
+    let mut entries = Vec::new();
+    while let Some(entry) = dir.next_entry().await? {
+        let path = entry.path();
+        match path.extension() {
+            Some(ext) if ext == OsStr::new("toml") => entries.push(path),
+            _ => continue,
+        }
+    }
+    entries.sort();
+    Ok(entries.into_iter().fold(builder, |builder, path| {
+        builder.add_async_source(AsyncFileSource::from(path, FileFormat::Toml))
+    }))
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use crate::daemon::Daemon;
+    use crate::{path, testing, write_synced};
+
+    use serde::{Deserialize, Serialize};
+    use std::path::PathBuf;
+
+    #[derive(Deserialize, Serialize, Copy, Clone, Default, PartialEq, Debug)]
+    struct TestSubstate {
+        subvalue: i32,
+    }
+
+    #[derive(Deserialize, Serialize, Copy, Clone, Default, PartialEq, Debug)]
+    #[serde(default)]
+    struct TestState {
+        substate: TestSubstate,
+        value: i32,
+    }
+
+    #[derive(Default)]
+    struct TestContext {
+        state: TestState,
+        config: TestState,
+    }
+
+    impl DaemonContext for TestContext {
+        type State = TestState;
+        type Config = TestState;
+        type Command = ();
+
+        fn user_config_path(&self) -> Result<PathBuf> {
+            Ok(path("user"))
+        }
+
+        fn system_config_path(&self) -> Result<PathBuf> {
+            Ok(path("system"))
+        }
+
+        fn state(&self) -> TestState {
+            self.state
+        }
+
+        async fn start(
+            &mut self,
+            state: Self::State,
+            config: Self::Config,
+            _daemon: &mut Daemon<Self>,
+        ) -> Result<()> {
+            self.state = state;
+            self.config = config;
+            Ok(())
+        }
+
+        async fn reload(&mut self, config: Self::Config, _daemon: &mut Daemon<Self>) -> Result<()> {
+            self.config = config;
+            Ok(())
+        }
+
+        async fn handle_command(
+            &mut self,
+            _cmd: Self::Command,
+            _daemon: &mut Daemon<Self>,
+        ) -> Result<()> {
+            Ok(())
+        }
+    }
+
+    #[tokio::test]
+    async fn test_read_state() {
+        let _h = testing::start();
+
+        let context = TestContext::default();
+        let state = read_state(&context).await.expect("read_state");
+
+        assert_eq!(state, TestState::default());
+
+        let state_path = context.state_path().expect("state_path");
+        create_dir_all(state_path.parent().unwrap())
+            .await
+            .expect("create_dir_all");
+
+        write_synced(
+            state_path,
+            "value = 1\n\n[substate]\nsubvalue = 2\n".as_bytes(),
+        )
+        .await
+        .expect("write");
+
+        let state = read_state(&context).await.expect("read_state");
+        assert_eq!(
+            state,
+            TestState {
+                value: 1,
+                substate: TestSubstate { subvalue: 2 }
+            }
+        );
+    }
+
+    #[tokio::test]
+    async fn test_read_extra_state() {
+        let _h = testing::start();
+
+        let context = TestContext::default();
+        let state_path = context.state_path().expect("state_path");
+        create_dir_all(state_path.parent().unwrap())
+            .await
+            .expect("create_dir_all");
+
+        write_synced(
+            state_path,
+            "value = 1\nvalue2 = 3\n\n[substate]\nsubvalue = 2\n".as_bytes(),
+        )
+        .await
+        .expect("write");
+
+        let state = read_state(&context).await.expect("read_state");
+        assert_eq!(
+            state,
+            TestState {
+                value: 1,
+                substate: TestSubstate { subvalue: 2 }
+            }
+        );
+    }
+
+    #[tokio::test]
+    async fn test_read_missing_state() {
+        let _h = testing::start();
+
+        let context = TestContext::default();
+        let state_path = context.state_path().expect("state_path");
+        create_dir_all(state_path.parent().unwrap())
+            .await
+            .expect("create_dir_all");
+
+        write_synced(state_path, "[substate]\nsubvalue = 2\n".as_bytes())
+            .await
+            .expect("write");
+
+        let state = read_state(&context).await.expect("read_state");
+        assert_eq!(
+            state,
+            TestState {
+                value: 0,
+                substate: TestSubstate { subvalue: 2 }
+            }
+        );
+    }
+
+    #[tokio::test]
+    async fn test_write_state() {
+        let _h = testing::start();
+
+        let mut context = TestContext::default();
+        let state_path = context.state_path().expect("state_path");
+
+        write_state(&context).await.expect("write_state");
+        let config = read_to_string(&state_path).await.expect("read_to_string");
+        assert_eq!(config, "value = 0\n\n[substate]\nsubvalue = 0\n");
+
+        context.state.value = 1;
+        write_state(&context).await.expect("write_state");
+        let config = read_to_string(&state_path).await.expect("read_to_string");
+        assert_eq!(config, "value = 1\n\n[substate]\nsubvalue = 0\n");
+    }
+
+    #[tokio::test]
+    async fn test_read_system_config() {
+        let _h = testing::start();
+
+        let context = TestContext::default();
+        let config = read_config(&context).await.expect("read_config");
+        assert_eq!(config, TestState::default());
+
+        let system_config_path = context.system_config_path().expect("system_config_path");
+        create_dir_all(&system_config_path)
+            .await
+            .expect("create_dir_all");
+
+        let config = read_config(&context).await.expect("read_config");
+        assert_eq!(config, TestState::default());
+
+        write_synced(
+            system_config_path.join("config.toml"),
+            "value = 1\n\n[substate]\nsubvalue = 2\n".as_bytes(),
+        )
+        .await
+        .expect("write");
+
+        let config = read_config(&context).await.expect("read_config");
+        assert_eq!(
+            config,
+            TestState {
+                value: 1,
+                substate: TestSubstate { subvalue: 2 }
+            }
+        );
+    }
+
+    #[tokio::test]
+    async fn test_read_user_config() {
+        let _h = testing::start();
+
+        let context = TestContext::default();
+        let config = read_config(&context).await.expect("read_config");
+        assert_eq!(config, TestState::default());
+
+        let user_config_path = context.user_config_path().expect("user_config_path");
+        create_dir_all(&user_config_path)
+            .await
+            .expect("create_dir_all");
+
+        let config = read_config(&context).await.expect("read_config");
+        assert_eq!(config, TestState::default());
+
+        write_synced(
+            user_config_path.join("config.toml"),
+            "value = 1\n\n[substate]\nsubvalue = 2\n".as_bytes(),
+        )
+        .await
+        .expect("write");
+
+        let config = read_config(&context).await.expect("read_config");
+        assert_eq!(
+            config,
+            TestState {
+                value: 1,
+                substate: TestSubstate { subvalue: 2 }
+            }
+        );
+    }
+
+    #[tokio::test]
+    async fn test_config_ordering() {
+        let _h = testing::start();
+
+        let context = TestContext::default();
+
+        let system_config_path = context.user_config_path().expect("system_config_path");
+        create_dir_all(&system_config_path)
+            .await
+            .expect("create_dir_all");
+
+        let user_config_path = context.user_config_path().expect("user_config_path");
+        create_dir_all(&user_config_path)
+            .await
+            .expect("create_dir_all");
+
+        write_synced(
+            system_config_path.join("config.toml"),
+            "value = 1\n\n[substate]\nsubvalue = 2\n".as_bytes(),
+        )
+        .await
+        .expect("write");
+
+        write_synced(
+            user_config_path.join("config.toml"),
+            "value = 3\n\n[substate]\nsubvalue = 4\n".as_bytes(),
+        )
+        .await
+        .expect("write");
+
+        let config = read_config(&context).await.expect("read_config");
+        assert_eq!(
+            config,
+            TestState {
+                value: 3,
+                substate: TestSubstate { subvalue: 4 }
+            }
+        );
+    }
+
+    #[tokio::test]
+    async fn test_config_partial_ordering() {
+        let _h = testing::start();
+
+        let context = TestContext::default();
+
+        let system_config_path = context.system_config_path().expect("system_config_path");
+        create_dir_all(&system_config_path)
+            .await
+            .expect("create_dir_all");
+
+        let user_config_path = context.user_config_path().expect("user_config_path");
+        create_dir_all(&user_config_path)
+            .await
+            .expect("create_dir_all");
+
+        write_synced(
+            system_config_path.join("config.toml"),
+            "value = 1\n\n[substate]\nsubvalue = 2\n".as_bytes(),
+        )
+        .await
+        .expect("write");
+
+        let config = read_config(&context).await.expect("read_config");
+        assert_eq!(
+            config,
+            TestState {
+                value: 1,
+                substate: TestSubstate { subvalue: 2 }
+            }
+        );
+
+        write_synced(
+            user_config_path.join("config.toml"),
+            "value = 3\n".as_bytes(),
+        )
+        .await
+        .expect("write");
+
+        let config = read_config(&context).await.expect("read_config");
+        assert_eq!(
+            config,
+            TestState {
+                value: 3,
+                substate: TestSubstate { subvalue: 2 }
+            }
+        );
+    }
+
+    #[tokio::test]
+    async fn test_read_user_config_fragments() {
+        let _h = testing::start();
+
+        let context = TestContext::default();
+
+        let user_config_path = context.user_config_path().expect("user_config_path");
+        create_dir_all(user_config_path.join("config.toml.d"))
+            .await
+            .expect("create_dir_all");
+
+        write_synced(
+            user_config_path.join("config.toml"),
+            "value = 1\n\n[substate]\nsubvalue = 2\n".as_bytes(),
+        )
+        .await
+        .expect("write");
+
+        let config = read_config(&context).await.expect("read_config");
+        assert_eq!(
+            config,
+            TestState {
+                value: 1,
+                substate: TestSubstate { subvalue: 2 }
+            }
+        );
+
+        write_synced(
+            user_config_path.join("config.toml.d/frag.toml"),
+            "[substate]\nsubvalue = 3\n".as_bytes(),
+        )
+        .await
+        .expect("write");
+
+        let config = read_config(&context).await.expect("read_config");
+        assert_eq!(
+            config,
+            TestState {
+                value: 1,
+                substate: TestSubstate { subvalue: 3 }
+            }
+        );
+    }
+
+    #[tokio::test]
+    async fn test_read_system_config_fragments() {
+        let _h = testing::start();
+
+        let context = TestContext::default();
+
+        let system_config_path = context.system_config_path().expect("system_config_path");
+        create_dir_all(system_config_path.join("config.toml.d"))
+            .await
+            .expect("create_dir_all");
+
+        write_synced(
+            system_config_path.join("config.toml"),
+            "value = 1\n\n[substate]\nsubvalue = 2\n".as_bytes(),
+        )
+        .await
+        .expect("write");
+
+        let config = read_config(&context).await.expect("read_config");
+        assert_eq!(
+            config,
+            TestState {
+                value: 1,
+                substate: TestSubstate { subvalue: 2 }
+            }
+        );
+
+        write_synced(
+            system_config_path.join("config.toml.d/frag.toml"),
+            "[substate]\nsubvalue = 3\n".as_bytes(),
+        )
+        .await
+        .expect("write");
+
+        let config = read_config(&context).await.expect("read_config");
+        assert_eq!(
+            config,
+            TestState {
+                value: 1,
+                substate: TestSubstate { subvalue: 3 }
+            }
+        );
+    }
 }