Use YAML for config (#352)

resolves #343 

If the flake url is a local path and `om.yaml` exists in the project
root, `omnix` will not invoke `nix eval .#om`.

Cargo.toml

@@ -50,6 +50,7 @@ serde = { version = "1.0.197", features = ["derive"] }
 serde_json = "1.0"
 serde_repr = "0.1.18"
 serde_with = { version = "3.2", features = ["json"] }
+serde_yaml = "0.9"
 shell-words = { version = "1.1.0" }
 sysinfo = "0.29.10"
 syntect = { version = "5.2.0", features = ["default-syntaxes"] }

crates/omnix-ci/src/command/core.rs

@@ -39,7 +39,8 @@ impl Command {
     pub async fn run(self, nixcmd: &NixCmd, verbose: bool) -> anyhow::Result<()> {
         tracing::info!("{}", "\n👟 Reading om.ci config from flake".bold());
         let url = self.get_flake_ref().to_flake_url().await?;
-        let cfg = OmConfig::from_flake_url(nixcmd, &url).await?;
+        let cfg = OmConfig::get(&url).await?;
+
         tracing::debug!("OmConfig: {cfg:?}");
         match self {
             Command::Run(cmd) => cmd.run(nixcmd, verbose, cfg).await,

crates/omnix-ci/src/config/core.rs

@@ -2,7 +2,7 @@
 
 #[cfg(test)]
 mod tests {
-    use nix_rs::{command::NixCmd, flake::url::FlakeUrl};
+    use nix_rs::flake::url::FlakeUrl;
     use omnix_common::config::OmConfig;
 
     use crate::config::subflakes::SubflakesConfig;
@@ -15,9 +15,7 @@ mod tests {
             "github:srid/haskell-flake/76214cf8b0d77ed763d1f093ddce16febaf07365#default.dev"
                 .to_string(),
         );
-        let cfg = OmConfig::from_flake_url(&NixCmd::default(), url)
-            .await
-            .unwrap();
+        let cfg = OmConfig::get(url).await.unwrap();
         let (config, attrs) = cfg.get_sub_config_under::<SubflakesConfig>("ci").unwrap();
         assert_eq!(attrs, &["dev"]);
         // assert_eq!(cfg.selected_subconfig, Some("dev".to_string()));

crates/omnix-cli/src/command/develop.rs

@@ -1,5 +1,5 @@
 use clap::Parser;
-use nix_rs::{command::NixCmd, flake::url::FlakeUrl};
+use nix_rs::flake::url::FlakeUrl;
 use omnix_common::config::OmConfig;
 
 /// Prepare to develop on a flake project
@@ -28,7 +28,7 @@ impl DevelopCommand {
     pub async fn run(&self) -> anyhow::Result<()> {
         let flake = self.flake_shell.without_attr();
 
-        let om_config = OmConfig::from_flake_url(NixCmd::get().await, &flake).await?;
+        let om_config = OmConfig::get(&flake).await?;
 
         tracing::info!("⌨️  Preparing to develop project: {:}", &flake);
         let prj = omnix_develop::core::Project::new(flake, om_config).await?;

crates/omnix-common/Cargo.toml

@@ -27,3 +27,4 @@ tracing = { workspace = true }
 tracing-subscriber = { workspace = true }
 which = { workspace = true }
 serde_json = { workspace = true }
+serde_yaml = { workspace = true }

crates/omnix-common/src/config.rs

@@ -4,7 +4,7 @@ use std::collections::BTreeMap;
 
 use nix_rs::{
     command::NixCmd,
-    flake::{eval::nix_eval_attr, url::FlakeUrl},
+    flake::{eval::nix_eval_attr, metadata::FlakeMetadata, url::FlakeUrl},
 };
 use serde::{de::DeserializeOwned, Deserialize};
 
@@ -24,12 +24,44 @@ pub struct OmConfig {
 }
 
 impl OmConfig {
-    /// Read the om configuration from the flake url
-    pub async fn from_flake_url(cmd: &NixCmd, flake_url: &FlakeUrl) -> Result<Self, OmConfigError> {
+    /// Fetch the `om` configuration from `om.yaml` if present, falling back to `om` config in flake output
+    pub async fn get(flake_url: &FlakeUrl) -> Result<Self, OmConfigError> {
+        match Self::from_yaml(flake_url).await? {
+            None => Self::from_flake(flake_url).await,
+            Some(config) => Ok(config),
+        }
+    }
+
+    /// Read the configuration from `om.yaml` in flake root
+    async fn from_yaml(flake_url: &FlakeUrl) -> Result<Option<Self>, OmConfigError> {
+        let path = if let Some(local_path) = flake_url.without_attr().as_local_path() {
+            local_path.to_path_buf()
+        } else {
+            FlakeMetadata::from_nix(NixCmd::get().await, flake_url)
+                .await?
+                .path
+        }
+        .join("om.yaml");
+
+        if !path.exists() {
+            return Ok(None);
+        }
+
+        let yaml_str = std::fs::read_to_string(path)?;
+        let config: OmConfigTree = serde_yaml::from_str(&yaml_str)?;
+        Ok(Some(OmConfig {
+            flake_url: flake_url.without_attr(),
+            reference: flake_url.get_attr().as_list(),
+            config,
+        }))
+    }
+
+    /// Read the configuration from `om` flake output
+    async fn from_flake(flake_url: &FlakeUrl) -> Result<Self, OmConfigError> {
         Ok(OmConfig {
             flake_url: flake_url.without_attr(),
             reference: flake_url.get_attr().as_list(),
-            config: nix_eval_attr(cmd, &flake_url.with_attr("om"))
+            config: nix_eval_attr(NixCmd::get().await, &flake_url.with_attr("om"))
                 .await?
                 .unwrap_or_default(),
         })
@@ -108,4 +140,12 @@ pub enum OmConfigError {
     /// Failed to parse JSON
     #[error("Failed to decode (json error): {0}")]
     DecodeErrorJson(#[from] serde_json::Error),
+
+    /// Failed to parse yaml
+    #[error("Failed to parse yaml: {0}")]
+    ParseYaml(#[from] serde_yaml::Error),
+
+    /// Failed to read yaml
+    #[error("Failed to read yaml: {0}")]
+    ReadYaml(#[from] std::io::Error),
 }

crates/omnix-health/src/lib.rs

@@ -12,7 +12,7 @@ use colored::Colorize;
 use check::direnv::Direnv;
 use nix_rs::env::OS;
 use nix_rs::flake::url::FlakeUrl;
-use nix_rs::{command::NixCmd, info::NixInfo};
+use nix_rs::info::NixInfo;
 use omnix_common::config::{OmConfig, OmConfigError};
 use omnix_common::markdown::render_markdown;
 use serde::{Deserialize, Serialize};
@@ -109,7 +109,7 @@ pub async fn run_all_checks_with(flake_url: Option<FlakeUrl>) -> anyhow::Result<
 
     let health: NixHealth = match flake_url.as_ref() {
         Some(flake_url) => {
-            let om_config = OmConfig::from_flake_url(NixCmd::get().await, flake_url).await?;
+            let om_config = OmConfig::get(flake_url).await?;
             NixHealth::from_om_config(&om_config)
         }
         None => Ok(NixHealth::default()),

crates/omnix-init/src/config.rs

@@ -1,7 +1,7 @@
 use std::fmt::{self, Display, Formatter};
 
 use colored::Colorize;
-use nix_rs::{command::NixCmd, flake::url::FlakeUrl};
+use nix_rs::flake::url::FlakeUrl;
 use omnix_common::config::OmConfig;
 
 use crate::template::Template;
@@ -33,7 +33,8 @@ impl<'a> Display for FlakeTemplate<'a> {
 
 /// Load templates from the given flake
 pub async fn load_templates<'a>(url: &FlakeUrl) -> anyhow::Result<Vec<FlakeTemplate>> {
-    let om_config = OmConfig::from_flake_url(NixCmd::get().await, url).await?;
+    let om_config = OmConfig::get(url).await?;
+
     let templates = om_config
         .config
         .get::<Template>("templates")?

om.yaml

@@ -0,0 +1,84 @@
+ci:
+  default:
+    omnix:
+      dir: .
+      steps:
+        flake-check:
+          enable: false
+        custom:
+          om-show:
+            type: app
+            args:
+              - show
+              - .
+          binary-size-is-small:
+            type: app
+            name: check-closure-size
+            systems:
+              - x86_64-linux
+          omnix-source-is-buildable:
+            type: app
+            name: omnix-source-is-buildable
+          cargo-tests:
+            type: devshell
+            command:
+              - just
+              - cargo-test
+            systems:
+              - x86_64-linux
+              - aarch64-darwin
+          cargo-clippy:
+            type: devshell
+            command:
+              - just
+              - clippy
+            systems:
+              - x86_64-linux
+              - aarch64-darwin
+          cargo-doc:
+            type: devshell
+            command:
+              - just
+              - cargo-doc
+            systems:
+              - x86_64-linux
+              - aarch64-darwin
+    doc:
+      dir: doc
+    registry:
+      dir: crates/omnix-init/registry
+      steps:
+        build:
+          enable: false
+        custom: {}
+    cli-test-dep-cache:
+      dir: crates/omnix-cli/tests
+      steps:
+        lockfile:
+          enable: false
+        flake_check:
+          enable: false
+        custom: {}
+health:
+  default:
+    nix-version:
+      min-required: "2.16.0"
+    caches:
+      required:
+        - https://om.cachix.org
+    direnv:
+      required: true
+develop:
+  default:
+    readme: |
+      🍾 Welcome to the **omnix** project
+
+      To run omnix,
+
+      ```sh-session
+      just watch <args>
+      ```
+
+      (Now, as you edit the Rust sources, the above will reload!)
+
+      🍎🍎 Run 'just' to see more commands. See <https://nixos.asia/en/vscode> for IDE setup.