Update metrics and fix Prometheus v3 breakage (#89)

tazz4843 · web-flow · commit 496e98a28ed4 · 2025-04-11T05:55:56.000+02:00
* Update `metrics` to latest version
* Explicitly define Content-Type in `/metrics` response to fix Prometheus v3 breakage
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -18,9 +18,9 @@ tracing-subscriber = { version = "0.3", features = ["env-filter"] }
 twilight-http-ratelimiting = { version = "0.16.0" }
 
 # Only used by the `expose-metrics` feature.
-metrics = { version = "0.21", optional = true }
-metrics-exporter-prometheus = { version = "0.12", default-features = false, optional = true }
-metrics-util = { version = "0.15", optional = true }
+metrics = { version = "0.24", optional = true }
+metrics-exporter-prometheus = { version = "0.16", default-features = false, optional = true }
+metrics-util = { version = "0.19", optional = true }
 lazy_static = { version = "1.4", optional = true }
 
 [dev-dependencies]
diff --git a/src/main.rs b/src/main.rs
@@ -35,6 +35,8 @@ use tokio::signal::unix::{signal, SignalKind};
 #[cfg(feature = "expose-metrics")]
 use std::time::Instant;
 
+#[cfg(feature = "expose-metrics")]
+use http::header::CONTENT_TYPE;
 #[cfg(feature = "expose-metrics")]
 use lazy_static::lazy_static;
 #[cfg(feature = "expose-metrics")]
@@ -98,7 +100,7 @@ async fn main() -> Result<(), Box<dyn Error>> {
             )
             .build_recorder();
         handle = Arc::new(recorder.handle());
-        metrics::set_boxed_recorder(Box::new(recorder))
+        metrics::set_global_recorder(Box::new(recorder))
             .expect("Failed to create metrics receiver!");
     }
 
@@ -401,7 +403,8 @@ async fn handle_request(
             .and_then(|header| header.to_str().ok())
             .unwrap_or("")
             .to_string();
-        histogram!(METRIC_KEY.as_str(), end - start, "method"=>m.to_string(), "route"=>p, "status"=>status.to_string(), "scope" => scope);
+        histogram!(METRIC_KEY.as_str(), "method"=>m.to_string(), "route"=>p, "status"=>status.to_string(), "scope" => scope)
+            .record(end - start);
     }
 
     debug!("{} {} ({}): {}", m, p, request_path, status);
@@ -412,6 +415,10 @@ async fn handle_request(
 #[cfg(feature = "expose-metrics")]
 fn handle_metrics(handle: Arc<PrometheusHandle>) -> Response<Body> {
     Response::builder()
+        .header(
+            CONTENT_TYPE,
+            HeaderValue::from_static("text/plain; version=0.0.4"),
+        )
         .body(Body::from(handle.render()))
         .unwrap()
 }
