Record datastore latency aggregated by batcher flush

limitador-server/src/main.rs

@@ -14,7 +14,6 @@ use crate::config::{
 use crate::envoy_rls::server::{run_envoy_rls_server, RateLimitHeaders};
 use crate::http_api::server::run_http_server;
 use crate::metrics::MetricsLayer;
-use ::metrics::histogram;
 use clap::{value_parser, Arg, ArgAction, Command};
 use const_format::formatcp;
 use limitador::counter::Counter;
@@ -271,11 +270,17 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             tracing_subscriber::fmt::layer()
         };
 
-        let metrics_layer = MetricsLayer::new().gather(
-            "should_rate_limit",
-            |timings| histogram!("counter_latency").record(Duration::from(timings).as_secs_f64()),
-            vec!["datastore"],
-        );
+        let metrics_layer = MetricsLayer::new()
+            .gather(
+                "should_rate_limit",
+                PrometheusMetrics::record_datastore_latency,
+                vec!["datastore"],
+            )
+            .gather(
+                "flush_batcher_and_update_counters",
+                PrometheusMetrics::record_datastore_latency,
+                vec!["datastore"],
+            );
 
         if !config.tracing_endpoint.is_empty() {
             global::set_text_map_propagator(TraceContextPropagator::new());

limitador-server/src/prometheus_metrics.rs

@@ -1,7 +1,9 @@
-use metrics::{counter, describe_counter, describe_gauge, describe_histogram, gauge};
+use metrics::{counter, describe_counter, describe_gauge, describe_histogram, gauge, histogram};
 use metrics_exporter_prometheus::{PrometheusBuilder, PrometheusHandle};
 use std::sync::Arc;
+use std::time::Duration;
 
+use crate::metrics::Timings;
 use limitador::limit::Namespace;
 
 const NAMESPACE_LABEL: &str = "limitador_namespace";
@@ -40,7 +42,7 @@ impl PrometheusMetrics {
         prometheus_handle: Arc<PrometheusHandle>,
     ) -> Self {
         describe_histogram!(
-            "counter_latency",
+            "datastore_latency",
             "Latency to the underlying counter datastore"
         );
         describe_counter!("authorized_calls", "Authorized calls");
@@ -91,6 +93,10 @@ impl PrometheusMetrics {
     pub fn gather_metrics(&self) -> String {
         self.prometheus_handle.render()
     }
+
+    pub fn record_datastore_latency(timings: Timings) {
+        histogram!("datastore_latency").record(Duration::from(timings).as_secs_f64())
+    }
 }
 
 #[cfg(test)]

limitador/src/storage/redis/redis_cached.rs

@@ -335,7 +335,7 @@ async fn update_counters<C: ConnectionLike>(
 
     Ok(res)
 }
-
+#[tracing::instrument(skip_all)]
 async fn flush_batcher_and_update_counters<C: ConnectionLike>(
     mut redis_conn: C,
     storage_is_alive: bool,