track responses by status code

Author: pietroalbini

src/metrics/instance.rs

@@ -19,7 +19,9 @@
 
 use crate::util::errors::AppResult;
 use crate::{app::App, db::DieselPool};
-use prometheus::{proto::MetricFamily, IntCounter, IntGauge, IntGaugeVec, HistogramVec};
+use prometheus::{
+    proto::MetricFamily, HistogramVec, IntCounter, IntCounterVec, IntGauge, IntGaugeVec,
+};
 
 metrics! {
     pub struct InstanceMetrics {
@@ -35,6 +37,8 @@ metrics! {
 
         /// Response times of our endpoints
         pub response_times: HistogramVec["endpoint"],
+        /// Nmber of responses per status code
+        pub responses_by_status_code_total: IntCounterVec["status"],
 
         /// Number of download requests that were served with an unconditional redirect.
         pub downloads_unconditional_redirects_total: IntCounter,

src/metrics/mod.rs

@@ -11,5 +11,6 @@ mod service;
 
 load_metric_type!(IntGauge as single);
 load_metric_type!(IntCounter as single);
+load_metric_type!(IntCounterVec as vec);
 load_metric_type!(IntGaugeVec as vec);
 load_metric_type!(HistogramVec as vec);

src/middleware/update_metrics.rs

@@ -30,6 +30,15 @@ impl Middleware for UpdateMetrics {
             .with_label_values(&[endpoint])
             .observe(req.elapsed().as_millis() as f64 / 1000.0);
 
+        let status = match &res {
+            Ok(res) => res.status().as_u16(),
+            Err(_) => 500,
+        };
+        metrics
+            .responses_by_status_code_total
+            .with_label_values(&[&status.to_string()])
+            .inc();
+
         res
     }
 }