Disable metrics layer if running in memory

limitador-server/src/main.rs

@@ -43,7 +43,6 @@ use std::path::Path;
 use std::sync::Arc;
 use std::time::Duration;
 use std::{env, process};
-use tracing_subscriber::Layer;
 
 #[cfg(feature = "distributed_storage")]
 use clap::parser::ValuesRef;
@@ -52,9 +51,10 @@ use sysinfo::{MemoryRefreshKind, RefreshKind, System};
 use thiserror::Error;
 use tokio::runtime::Handle;
 use tracing::level_filters::LevelFilter;
+use tracing::Subscriber;
 use tracing_subscriber::fmt::format::FmtSpan;
-use tracing_subscriber::layer::SubscriberExt;
 use tracing_subscriber::util::SubscriberInitExt;
+use tracing_subscriber::{layer::SubscriberExt, Layer};
 
 mod envoy_rls;
 mod http_api;
@@ -760,15 +760,7 @@ fn configure_tracing_subscriber(config: &Configuration) {
             .unwrap_or(LevelFilter::ERROR)
     });
 
-    let fmt_layer = tracing_subscriber::fmt::layer()
-        .with_span_events(if level >= LevelFilter::DEBUG {
-            FmtSpan::CLOSE
-        } else {
-            FmtSpan::NONE
-        })
-        .with_filter(level);
-
-    let metrics_layer = MetricsLayer::new()
+    let metrics_layer = MetricsLayer::default()
         .gather(
             "should_rate_limit",
             PrometheusMetrics::record_datastore_latency,
@@ -794,22 +786,41 @@ fn configure_tracing_subscriber(config: &Configuration) {
                 .with_trace_config(trace::config().with_resource(Resource::new(vec![
                     KeyValue::new("service.name", "limitador"),
                 ])))
-                .install_batch(opentelemetry_sdk::runtime::Tokio)?;
+                .install_batch(opentelemetry_sdk::runtime::Tokio)
+                .expect("error installing tokio tracing exporter");
 
         let telemetry_layer = tracing_opentelemetry::layer().with_tracer(tracer);
 
         // Init tracing subscriber with telemetry
         tracing_subscriber::registry()
             .with(metrics_layer)
-            .with(fmt_layer)
+            .with(fmt_layer(level))
             .with(level.max(LevelFilter::INFO))
             .with(telemetry_layer)
-            .init();
+            .init()
     } else {
-        // Init tracing subscriber without telemetry
-        tracing_subscriber::registry()
-            .with(metrics_layer)
-            .with(fmt_layer)
-            .init();
-    };
+        // If running in memory initialize without metrics, otherwise include the metrics layer
+        match config.storage {
+            StorageConfiguration::InMemory(_) => {
+                tracing_subscriber::registry().with(fmt_layer(level)).init()
+            }
+            _ => tracing_subscriber::registry()
+                .with(metrics_layer)
+                .with(fmt_layer(level))
+                .init(),
+        }
+    }
+}
+
+fn fmt_layer<S>(level: LevelFilter) -> impl Layer<S>
+where
+    S: Subscriber + for<'a> tracing_subscriber::registry::LookupSpan<'a>,
+{
+    tracing_subscriber::fmt::layer()
+        .with_span_events(if level >= LevelFilter::DEBUG {
+            FmtSpan::CLOSE
+        } else {
+            FmtSpan::NONE
+        })
+        .with_filter(level)
 }