merge proxying metrics accross workers

bin/src/cli.rs

@@ -231,7 +231,7 @@ pub enum MetricsCmd {
         #[clap(
             short = 'w',
             long = "workers",
-            help = "display metrics of each worker, without flattening by cluster id (takes more space)"
+            help = "display metrics of each worker, without merging by metric name or cluster id (takes more space)"
         )]
         workers: bool,
     },

bin/src/command/requests.rs

@@ -583,10 +583,11 @@ impl GatheringTask for QueryMetricsTask {
             main: main_metrics,
             clusters: BTreeMap::new(),
             workers: workers_metrics,
+            proxying: BTreeMap::new(),
         };
 
         if !self.options.workers && server.workers.len() > 1 {
-            aggregated_metrics.merge_cluster_metrics();
+            aggregated_metrics.merge_metrics();
         }
 
         client.finish_ok_with_content(

command/src/command.proto

@@ -578,12 +578,18 @@ message AvailableMetrics {
 
 // Aggregated metrics of main process & workers
 message AggregatedMetrics {
+    // metrics about the main process.
     // metric_name -> metric_value
     map<string, FilteredMetrics> main = 1;
+    // details of worker metrics, with clusters and backends.
     // worker_id -> worker_metrics
     map<string, WorkerMetrics> workers = 2;
+    // if present, contains metrics of clusters and their backends, merged across all workers.
     // cluster_id -> cluster_metrics
     map<string, ClusterMetrics> clusters = 3;
+    // if present, proxying metrics, merged accross all workers.
+    // metric_name -> metric_value
+    map<string, FilteredMetrics> proxying = 4;
 }
 
 // All metrics of a worker: proxy and clusters

command/src/proto/display.rs

@@ -240,10 +240,17 @@ pub fn print_metrics(aggregated_metrics: &AggregatedMetrics) -> Result<(), Displ
     println!("\nMAIN PROCESS\n============");
     print_proxy_metrics(&aggregated_metrics.main);
 
+    if aggregated_metrics.proxying.len() != 0 {
+        println!("\nPROXYING\n============");
+        print_proxy_metrics(&aggregated_metrics.proxying);
+    }
+
     // workers
-    for (worker_id, worker_metrics) in aggregated_metrics.workers.iter() {
-        println!("\nWorker {worker_id}\n=========");
-        print_worker_metrics(worker_metrics)?;
+    for (worker_id, worker) in aggregated_metrics.workers.iter() {
+        if worker.clusters.len() != 0 && worker.proxy.len() != 0 {
+            println!("\nWorker {worker_id}\n=========");
+            print_worker_metrics(worker)?;
+        }
     }
 
     // clusters

command/src/proto/mod.rs

@@ -42,16 +42,27 @@ impl From<command::request::RequestType> for command::Request {
 }
 
 impl AggregatedMetrics {
-    /// Merge cluster metrics that were received from several workers
+    /// Merge metrics that were received from several workers
     ///
-    /// Each workers serves the same clusters and gathers metrics on them,
-    /// which means we have to reduce each metric from N instances to 1.
-    pub fn merge_cluster_metrics(&mut self) {
-        for (_worker_id, worker_metrics) in &mut self.workers {
-            // avoid copying the cluster metrics by taking them
-            let clusters = std::mem::take(&mut worker_metrics.clusters);
+    /// Each worker gather the same kind of metrics,
+    /// for its own proxying logic, and for the same clusters with their backends.
+    /// This means we have to reduce each metric from N instances to 1.
+    pub fn merge_metrics(&mut self) {
+        // avoid copying the worker metrics, by taking them
+        let workers = std::mem::take(&mut self.workers);
 
-            for (cluster_id, mut cluster_metrics) in clusters {
+        for (_worker_id, worker) in workers {
+            for (metric_name, new_value) in worker.proxy {
+                if !new_value.is_mergeable() {
+                    continue;
+                }
+                self.proxying
+                    .entry(metric_name)
+                    .and_modify(|old_value| old_value.merge(&new_value))
+                    .or_insert(new_value);
+            }
+
+            for (cluster_id, mut cluster_metrics) in worker.clusters {
                 for (metric_name, new_value) in cluster_metrics.cluster {
                     if !new_value.is_mergeable() {
                         continue;