refactor: streamline metrics configuration and initialization

Author: Ngha-Boris

.env.template

@@ -7,7 +7,7 @@ APP_ENV=development # development | production
 APP_SERVER__HOST=0.0.0.0
 APP_SERVER__DOMAIN=statuslist.example.com
 APP_SERVER__PORT=8000
-APP_SERVER__ENABLE_METRICS=bool
+APP_SERVER__ENABLE_METRICS=false
 
 # Certificate
 APP_SERVER__CERT__EMAIL=support@example.com

docker-compose.yml

@@ -73,7 +73,6 @@ services:
     environment:
       APP_ENV: ${APP_ENV:-development}
       APP_SERVER__ENABLE_METRICS: ${APP_SERVER__ENABLE_METRICS:-true}
-      APP_SERVER__EXPOSE_METRICS_ENDPOINT: ${APP_SERVER__EXPOSE_METRICS_ENDPOINT:-true}
     ports:
       - 8000:8000
     depends_on:

src/main.rs

@@ -3,7 +3,6 @@ use dotenvy::dotenv;
 use rustls::crypto::aws_lc_rs;
 use status_list_server::cert_manager::setup_cert_renewal_scheduler;
 use status_list_server::state::build_state;
-use status_list_server::utils::metrics::{setup_metrics, start_metrics_collector};
 use status_list_server::{config::Config as AppConfig, startup::HttpServer};
 #[cfg(not(target_env = "msvc"))]
 use tikv_jemallocator::Jemalloc;
@@ -33,23 +32,7 @@ async fn main() -> Result<()> {
     let cert_manager = app_state.cert_manager.clone();
     setup_cert_renewal_scheduler(cert_manager.clone()).await?;
 
-    // Setup metrics if enabled
-    let metrics_handle = if config.server.enable_metrics {
-        match setup_metrics() {
-            Ok(handle) => {
-                start_metrics_collector();
-                Some(handle)
-            }
-            Err(e) => {
-                warn!("Failed to setup metrics: {e}");
-                None
-            }
-        }
-    } else {
-        None
-    };
-
-    let http_server = HttpServer::new(&config, app_state, metrics_handle).await?;
+    let http_server = HttpServer::new(&config, app_state).await?;
 
     // Initial certificate request
     tokio::spawn(async move {

src/startup.rs

@@ -6,7 +6,6 @@ use axum::{
 };
 use color_eyre::eyre::Context;
 use hyper::Method;
-use metrics_exporter_prometheus::PrometheusHandle;
 use tokio::net::TcpListener;
 use tower_http::{
     catch_panic::CatchPanicLayer,
@@ -38,11 +37,7 @@ pub struct HttpServer {
 }
 
 impl HttpServer {
-    pub async fn new(
-        config: &Config,
-        state: AppState,
-        metrics_handle: Option<PrometheusHandle>,
-    ) -> color_eyre::Result<Self> {
+    pub async fn new(config: &Config, state: AppState) -> color_eyre::Result<Self> {
         let cors = CorsLayer::new()
             .allow_methods([Method::GET, Method::POST, Method::OPTIONS])
             .allow_origin(Any)
@@ -58,16 +53,7 @@ impl HttpServer {
             .layer(cors)
             .with_state(state);
 
-        if config.server.enable_metrics {
-            if let Some(handle) = metrics_handle {
-                tracing::info!("StatusList Monitor: ENABLED (Metrics at /metrics)");
-                router = router.route("/metrics", get(move || metrics_handler(handle)));
-            } else {
-                tracing::warn!("Metrics enabled in config but no handle provided");
-            }
-        } else {
-            tracing::info!("StatusList Monitor: DISABLED");
-        }
+        router = metrics(router, config);
 
         let listener = TcpListener::bind(format!("{}:{}", config.server.host, config.server.port))
             .await
@@ -95,3 +81,22 @@ fn status_list_routes(state: AppState) -> Router<AppState> {
         .merge(protected_routes)
         .route("/{list_id}", get(get_status_list))
 }
+
+fn metrics(router: Router, config: &Config) -> Router {
+    if config.server.enable_metrics {
+        match crate::utils::metrics::setup_metrics() {
+            Ok(handle) => {
+                crate::utils::metrics::start_metrics_collector();
+                tracing::info!("StatusList Monitor: ENABLED (Metrics at /metrics)");
+                router.route("/metrics", get(move || metrics_handler(handle)))
+            }
+            Err(e) => {
+                tracing::warn!("Failed to setup metrics: {e}");
+                router
+            }
+        }
+    } else {
+        tracing::info!("StatusList Monitor: DISABLED");
+        router
+    }
+}