course-service 0.2.0

//! Course Service binary — boot sequence for the REST API.
//!
//! `Config::from_env` → `db::create_connection` → `SearchEngine` →
//! matcher → `AppState` → `api::rest::serve`. Mirrors the person-service
//! boot sequence so operators get one shape to learn.
//!
//! Migrations are NOT auto-run; see `README.md` for the bring-up
//! sequence.

#[cfg(target_env = "musl")]
#[global_allocator]
static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;

use course_service::{
    api::rest::{AppState, serve},
    config::Config,
    db::create_connection,
    matching::CourseMatcher,
    search::SearchEngine,
};
use tracing_subscriber::EnvFilter;

/// Process entry point. Delegates to [`run`] and translates any startup
/// error into a non-zero [`ExitCode`](std::process::ExitCode) after
/// printing it to stderr (the tracing subscriber may not be up yet).
#[tokio::main]
async fn main() -> std::process::ExitCode {
    if let Err(err) = run().await {
        eprintln!("course-service failed to start: {err}");
        return std::process::ExitCode::FAILURE;
    }
    std::process::ExitCode::SUCCESS
}

/// Assemble and run the service: load config from the environment, init
/// tracing, open the database connection, build the search engine and
/// matcher, wire them into [`AppState`], and hand off to
/// [`serve`](course_service::api::rest::serve). Returns only when the
/// server stops or a startup step fails.
async fn run() -> Result<(), Box<dyn std::error::Error>> {
    let config = Config::from_env()?;

    let filter = EnvFilter::try_from_default_env()
        .or_else(|_| EnvFilter::try_new(&config.observability.log_level))
        .unwrap_or_else(|_| EnvFilter::new("info"));
    tracing_subscriber::fmt()
        .with_env_filter(filter)
        .compact()
        .init();

    tracing::info!(
        version = env!("CARGO_PKG_VERSION"),
        service = config.observability.service_name.as_str(),
        host = config.server.host.as_str(),
        port = config.server.port,
        "course-service starting",
    );

    let db = create_connection(&config.database).await?;
    tracing::info!(
        url = mask_db_url(&config.database.url),
        "database connected"
    );

    let search_engine = SearchEngine::new(&config.search.index_path)?;
    tracing::info!(
        path = config.search.index_path.as_str(),
        "search index ready"
    );

    let matcher = CourseMatcher::new(config.matching.clone());
    let state = AppState::new(db, search_engine, matcher, config);

    serve(state).await?;
    Ok(())
}

/// Redact the userinfo (`user:password`) segment of a database URL so it
/// is safe to emit in a startup log line. Replaces everything between the
/// `://` scheme separator and the `@` host delimiter with
/// `<credentials>`; returns the input unchanged when no `@`/`://` is
/// found.
fn mask_db_url(url: &str) -> String {
    if let Some(at) = url.find('@') {
        if let Some(scheme_end) = url.find("://") {
            let scheme = &url[..scheme_end + 3];
            return format!("{scheme}<credentials>@{}", &url[at + 1..]);
        }
    }
    url.to_string()
}