1 files changed, 56 insertions, 0 deletions
diff --git a/crates/atuin-server/src/metrics.rs b/crates/atuin-server/src/metrics.rs
new file mode 100644
index 00000000..0a7ac6bd
--- /dev/null
+++ b/crates/atuin-server/src/metrics.rs
@@ -0,0 +1,56 @@
+use std::time::Instant;
+
+use axum::{
+    extract::{MatchedPath, Request},
+    middleware::Next,
+    response::IntoResponse,
+};
+use metrics_exporter_prometheus::{Matcher, PrometheusBuilder, PrometheusHandle};
+
+pub fn setup_metrics_recorder() -> PrometheusHandle {
+    const EXPONENTIAL_SECONDS: &[f64] = &[
+        0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 10.0,
+    ];
+
+    PrometheusBuilder::new()
+        .set_buckets_for_metric(
+            Matcher::Full("http_requests_duration_seconds".to_string()),
+            EXPONENTIAL_SECONDS,
+        )
+        .unwrap()
+        .install_recorder()
+        .unwrap()
+}
+
+/// Middleware to record some common HTTP metrics
+/// Generic over B to allow for arbitrary body types (eg Vec<u8>, Streams, a deserialized thing, etc)
+/// Someday tower-http might provide a metrics middleware: https://github.com/tower-rs/tower-http/issues/57
+pub async fn track_metrics(req: Request, next: Next) -> impl IntoResponse {
+    let start = Instant::now();
+
+    let path = if let Some(matched_path) = req.extensions().get::<MatchedPath>() {
+        matched_path.as_str().to_owned()
+    } else {
+        req.uri().path().to_owned()
+    };
+
+    let method = req.method().clone();
+
+    // Run the rest of the request handling first, so we can measure it and get response
+    // codes.
+    let response = next.run(req).await;
+
+    let latency = start.elapsed().as_secs_f64();
+    let status = response.status().as_u16().to_string();
+
+    let labels = [
+        ("method", method.to_string()),
+        ("path", path),
+        ("status", status),
+    ];
+
+    metrics::increment_counter!("http_requests_total", &labels);
+    metrics::histogram!("http_requests_duration_seconds", latency, &labels);
+
+    response
+}