fix(cli): Respect the --cfg flag (#506)

Use the --cfg flag to load the configuration file for `iroh`.

This does not affect the config files for any of the managed
processes like iroh-p2p etc.

* Make argument a slice rather than a vec, the vec was not really used.
* Test the priority order and document it.

iroh-api/src/api.rs

@@ -39,12 +39,12 @@ impl Api {
  overrides_map: HashMap<String, String>,
  ) -> Result<Self> {
  let cfg_path = iroh_config_path(CONFIG_FILE_NAME)?;
- let sources = vec![Some(cfg_path.as_path()), config_path];
+ let sources = [Some(cfg_path.as_path()), config_path];
  let config = make_config(
  // default
  Config::default(),
  // potential config files
- sources,
+ &sources,
  // env var prefix for this config
  ENV_PREFIX,
  // map of present command line arguments

iroh-gateway/src/main.rs

@@ -23,12 +23,12 @@ async fn main() -> Result<()> {
  let args = Args::parse();
 
  let cfg_path = iroh_config_path(CONFIG_FILE_NAME)?;
- let sources = vec![Some(cfg_path.as_path()), args.cfg.as_deref()];
+ let sources = [Some(cfg_path.as_path()), args.cfg.as_deref()];
  let mut config = make_config(
  // default
  Config::default(),
  // potential config files
- sources,
+ &sources,
  // env var prefix for this config
  ENV_PREFIX,
  // map of present command line arguments

iroh-one/src/main.rs

@@ -25,12 +25,12 @@ async fn main() -> Result<()> {
  let args = Args::parse();
 
  let cfg_path = iroh_config_path(CONFIG_FILE_NAME)?;
- let sources = vec![Some(cfg_path.as_path()), args.cfg.as_deref()];
+ let sources = [Some(cfg_path.as_path()), args.cfg.as_deref()];
  let mut config = make_config(
  // default
  Config::default(),
  // potential config files
- sources,
+ &sources,
  // env var prefix for this config
  ENV_PREFIX,
  // map of present command line arguments

iroh-p2p/src/main.rs

@@ -27,12 +27,12 @@ fn main() -> Result<()> {
 
  // TODO: configurable network
  let cfg_path = iroh_config_path(CONFIG_FILE_NAME)?;
- let sources = vec![Some(cfg_path.as_path()), args.cfg.as_deref()];
+ let sources = [Some(cfg_path.as_path()), args.cfg.as_deref()];
  let network_config = make_config(
  // default
  Config::default_grpc(),
  // potential config files
- sources,
+ &sources,
  // env var prefix for this config
  ENV_PREFIX,
  // map of present command line arguments

iroh-store/src/main.rs

@@ -20,7 +20,7 @@ async fn main() -> anyhow::Result<()> {
  println!("Starting iroh-store, version {version}");
 
  let config_path = iroh_config_path(CONFIG_FILE_NAME)?;
- let sources = vec![Some(config_path.as_path()), args.cfg.as_deref()];
+ let sources = &[Some(config_path.as_path()), args.cfg.as_deref()];
  let config_data_path = config_data_path(args.path.clone())?;
  let config = make_config(
  // default

iroh-util/Cargo.toml

@@ -23,5 +23,8 @@ thiserror = "1.0"
 toml = "0.5.9"
 tracing = "0.1.34"
 
+[dev-dependencies]
+testdir = "0.6.0"
+
 [target.'cfg(unix)'.dev-dependencies]
 nix = "0.25"

iroh-util/src/lib.rs

@@ -142,18 +142,20 @@ impl Source for MetricsSource {
  }
 }
 
-/// make a config using a default, file sources, environment variables, and commandline flag
-/// overrides
+/// Make a config using a default, files, environment variables, and commandline flags.
 ///
-/// environment variables are expected to start with the `env_prefix`. Nested fields can be
+/// Later items in the *file_paths* slice will have a higher priority than earlier ones.
+///
+/// Environment variables are expected to start with the *env_prefix*. Nested fields can be
 /// accessed using `.`, if your environment allows env vars with `.`
 ///
-/// Note: For the metrics configuration env vars, it is recommended to use the metrics specific
-/// prefix `IROH_METRICS` to set a field in the metrics config. You can use the above dot notation to set
-/// a metrics field, eg, `IROH_CONFIG_METRICS.SERVICE_NAME`, but only if your environment allows it
+/// Note: For the metrics configuration env vars, it is recommended to use the metrics
+/// specific prefix `IROH_METRICS` to set a field in the metrics config. You can use the
+/// above dot notation to set a metrics field, eg, `IROH_CONFIG_METRICS.SERVICE_NAME`, but
+/// only if your environment allows it
 pub fn make_config<T, S, V>(
  default: T,
- file_paths: Vec<Option<&Path>>,
+ file_paths: &[Option<&Path>],
  env_prefix: &str,
  flag_overrides: HashMap<S, V>,
 ) -> Result<T>
@@ -166,7 +168,7 @@ where
  let mut builder = Config::builder().add_source(default);
 
  // layer on config options from files
- for path in file_paths.into_iter().flatten() {
+ for path in file_paths.iter().flatten() {
  if path.exists() {
  let p = path.to_str().ok_or_else(|| anyhow::anyhow!("empty path"))?;
  builder = builder.add_source(File::with_name(p));
@@ -238,6 +240,9 @@ pub fn increase_fd_limit() -> std::io::Result<u64> {
 
 #[cfg(test)]
 mod tests {
+ use serde::Deserialize;
+ use testdir::testdir;
+
  use super::*;
 
  #[test]
@@ -247,4 +252,41 @@ mod tests {
  let got = got.replace('\\', "/"); // handle windows paths
  assert!(got.ends_with("/iroh/foo.bar"));
  }
+
+ #[derive(Debug, Clone, Deserialize)]
+ struct Config {
+ item: String,
+ }
+
+ impl Source for Config {
+ fn clone_into_box(&self) -> Box<dyn Source + Send + Sync> {
+ Box::new(self.clone())
+ }
+
+ fn collect(&self) -> Result<Map<String, Value>, ConfigError> {
+ let mut map = Map::new();
+ insert_into_config_map(&mut map, "item", self.item.clone());
+ Ok(map)
+ }
+ }
+
+ #[test]
+ fn test_make_config_priority() {
+ // Asserting that later items have a higher priority
+ let cfgdir = testdir!();
+ let cfgfile0 = cfgdir.join("cfg0.toml");
+ std::fs::write(&cfgfile0, r#"item = "zero""#).unwrap();
+ let cfgfile1 = cfgdir.join("cfg1.toml");
+ std::fs::write(&cfgfile1, r#"item = "one""#).unwrap();
+ let cfg = make_config(
+ Config {
+ item: String::from("default"),
+ },
+ &[Some(cfgfile0.as_path()), Some(cfgfile1.as_path())],
+ "NO_PREFIX_PLEASE_",
+ HashMap::<String, String>::new(),
+ )
+ .unwrap();
+ assert_eq!(cfg.item, "one");
+ }
 }

iroh-util/tests/config.rs

@@ -179,7 +179,7 @@ fn test_make_config() {
  || {
  let got = make_config(
  TestConfig::new(),
- vec![
+ &[
  Some(&PathBuf::from(CONFIG_A)),
  Some(&PathBuf::from(CONFIG_B)),
  None,

iroh/src/run.rs

@@ -85,13 +85,12 @@ enum Commands {
 impl Cli {
  pub async fn run(&self) -> Result<()> {
  let config_path = iroh_config_path(CONFIG_FILE_NAME)?;
- // TODO(b5): allow suppliying some sort of config flag. maybe --config-cli?
- let sources = vec![Some(config_path.as_path())];
+ let sources = [Some(config_path.as_path()), self.cfg.as_deref()];
  let config = make_config(
  // default
  Config::new(),
  // potential config files
- sources,
+ &sources,
  // env var prefix for this config
  ENV_PREFIX,
  // map of present command line arguments