maestro/crates/maestro-web/src/config.rs

//! `maestro-web` view over the unified Maestro config.

use std::net::SocketAddr;
use std::path::{Path, PathBuf};

use maestro_config::MaestroConfigFile;

pub use maestro_config::default_config_path;

use maestro_config::WebSection;

/// Default bind address when neither env nor file specify one.
pub const DEFAULT_BIND_ADDR: &str = "127.0.0.1:8080";
/// Default daemon URL `maestro-web` reverse-proxies to.
pub const DEFAULT_DAEMON_URL: &str = "http://127.0.0.1:7070";

pub const ENV_WEB_BIND_ADDR: &str = "MAESTRO_WEB_BIND_ADDR";
pub const ENV_WEB_DAEMON_URL: &str = "MAESTRO_WEB_DAEMON_URL";

fn default_bind_addr() -> SocketAddr {
    DEFAULT_BIND_ADDR.parse().expect("valid default bind_addr")
}

#[derive(Debug, thiserror::Error)]
pub enum WebConfigError {
    #[error(transparent)]
    Inner(#[from] maestro_config::ConfigError),
}

/// Resolved runtime configuration for the `maestro-web` binary.
#[derive(Debug, Clone)]
pub struct WebConfig {
    pub bind_addr: SocketAddr,
    /// Daemon HTTP base URL — e.g. `http://127.0.0.1:7070`. Always a base
    /// without trailing slash and without a path.
    pub daemon_url: String,
}

#[derive(Debug, Clone, Default)]
pub struct EnvOverrides {
    pub bind_addr: Option<String>,
    pub daemon_url: Option<String>,
}

impl EnvOverrides {
    pub fn from_env() -> Self {
        Self {
            bind_addr: std::env::var(ENV_WEB_BIND_ADDR).ok(),
            daemon_url: std::env::var(ENV_WEB_DAEMON_URL).ok(),
        }
    }
}

/// Resolve the runtime configuration. Missing-file is fine: every field has
/// a default and the binary is happy to run with no config.toml at all.
pub fn load_config(path: &Path, env: EnvOverrides) -> Result<WebConfig, WebConfigError> {
    let file = MaestroConfigFile::load(path)?;
    resolve_with(file.web, env)
}

fn resolve_with(web: WebSection, env: EnvOverrides) -> Result<WebConfig, WebConfigError> {
    let bind_addr = match env.bind_addr {
        Some(raw) => maestro_config::parse_bind_addr(&raw, ENV_WEB_BIND_ADDR)?,
        None => web.bind_addr.unwrap_or_else(default_bind_addr),
    };

    let daemon_url = env
        .daemon_url
        .or(web.daemon_url)
        .unwrap_or_else(|| DEFAULT_DAEMON_URL.to_string())
        .trim_end_matches('/')
        .to_string();

    Ok(WebConfig {
        bind_addr,
        daemon_url,
    })
}

/// Standard state dir (mostly so callers have a place to put logs — the
/// binary itself is stateless).
pub fn default_state_dir() -> Result<PathBuf, WebConfigError> {
    Ok(maestro_config::default_state_dir("maestro-web")?)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn defaults_when_file_missing() {
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("does-not-exist.toml");
        let cfg = load_config(&path, EnvOverrides::default()).unwrap();
        assert_eq!(cfg.bind_addr, default_bind_addr());
        assert_eq!(cfg.daemon_url, "http://127.0.0.1:7070");
    }

    #[test]
    fn reads_web_section_from_file() {
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        std::fs::write(
            &path,
            r#"
[web]
bind_addr = "127.0.0.1:9090"
daemon_url = "http://127.0.0.1:9070"
"#,
        )
        .unwrap();
        let cfg = load_config(&path, EnvOverrides::default()).unwrap();
        assert_eq!(cfg.bind_addr, "127.0.0.1:9090".parse().unwrap());
        assert_eq!(cfg.daemon_url, "http://127.0.0.1:9070");
    }

    #[test]
    fn env_beats_file() {
        let dir = tempfile::tempdir().unwrap();
        let path = dir.path().join("config.toml");
        std::fs::write(
            &path,
            r#"
[web]
bind_addr = "127.0.0.1:9090"
daemon_url = "http://127.0.0.1:9070"
"#,
        )
        .unwrap();
        let env = EnvOverrides {
            bind_addr: Some("0.0.0.0:8080".into()),
            daemon_url: Some("http://daemon:7070".into()),
        };
        let cfg = load_config(&path, env).unwrap();
        assert_eq!(cfg.bind_addr, "0.0.0.0:8080".parse().unwrap());
        assert_eq!(cfg.daemon_url, "http://daemon:7070");
    }

    #[test]
    fn daemon_url_strips_trailing_slash() {
        let env = EnvOverrides {
            daemon_url: Some("http://daemon:7070/".into()),
            ..Default::default()
        };
        let cfg = resolve_with(WebSection::default(), env).unwrap();
        assert_eq!(cfg.daemon_url, "http://daemon:7070");
    }
}