Add branch_id field to proxy_io_bytes_per_client metric.

Since we allow switching endpoints between different branches, it is important to use composite key.
Otherwise, we may try to calculate delta between metric values for two different branches.

proxy/src/metrics.rs

@@ -21,6 +21,7 @@ const PROXY_IO_BYTES_PER_CLIENT: &str = "proxy_io_bytes_per_client";
 #[derive(Eq, Hash, PartialEq, Serialize, Debug)]
 pub struct Ids {
     pub endpoint_id: String,
+    pub branch_id: String,
 }
 
 pub async fn task_main(config: &MetricCollectionConfig) -> anyhow::Result<()> {
@@ -74,12 +75,23 @@ fn gather_proxy_io_bytes_per_client() -> Vec<(Ids, (u64, DateTime<Utc>))> {
                         .find(|l| l.get_name() == "endpoint_id")
                         .unwrap()
                         .get_value();
+                    let branch_id = ms
+                        .get_label()
+                        .iter()
+                        .find(|l| l.get_name() == "branch_id")
+                        .unwrap()
+                        .get_value();
+
                     let value = ms.get_counter().get_value() as u64;
 
-                    debug!("endpoint_id:val - {}: {}", endpoint_id, value);
+                    debug!(
+                        "branch_id {} endpoint_id {} val: {}",
+                        branch_id, endpoint_id, value
+                    );
                     current_metrics.push((
                         Ids {
                             endpoint_id: endpoint_id.to_string(),
+                            branch_id: "".to_string(),
                         },
                         (value, Utc::now()),
                     ));
@@ -131,6 +143,7 @@ async fn collect_metrics_iteration(
                 value,
                 extra: Ids {
                     endpoint_id: curr_key.endpoint_id.clone(),
+                    branch_id: curr_key.branch_id.clone(),
                 },
             })
         })
@@ -172,6 +185,7 @@ async fn collect_metrics_iteration(
                 cached_metrics
                     .entry(Ids {
                         endpoint_id: send_metric.extra.endpoint_id.clone(),
+                        branch_id: send_metric.extra.branch_id.clone(),
                     })
                     // update cached value (add delta) and time
                     .and_modify(|e| {