ref(autoscaling): add prefix to autoscaling metrics (#4530)

This PR adds the `relay_` prefix to all produced metrics so they can be
specifically queried. The metrics names are quite generic and with the
prefix they are easier to find and use

Author: Litarnus

relay-server/src/endpoints/autoscaling.rs

@@ -28,12 +28,14 @@ fn to_prometheus_string(data: &AutoscalingData) -> String {
 
     append_data_row(&mut result, "memory_usage", data.memory_usage);
     append_data_row(&mut result, "up", data.up);
-    append_data_row(&mut result, "item_count", data.item_count);
-    append_data_row(&mut result, "total_size", data.total_size);
+    append_data_row(&mut result, "spool_item_count", data.item_count);
+    append_data_row(&mut result, "spool_total_size", data.total_size);
     result
 }
 
 fn append_data_row(result: &mut String, label: &str, data: impl Display) {
+    // Metrics are automatically prefixed with "relay_"
+    result.push_str("relay_");
     result.push_str(label);
     result.push(' ');
     result.push_str(&data.to_string());
@@ -55,7 +57,11 @@ mod test {
         let result = super::to_prometheus_string(&data);
         assert_eq!(
             result,
-            "memory_usage 0.75\nup 1\nitem_count 10\ntotal_size 30\n"
+            r#"relay_memory_usage 0.75
+relay_up 1
+relay_spool_item_count 10
+relay_spool_total_size 30
+"#
         );
     }
 }

relay-server/src/services/buffer/mod.rs

@@ -905,7 +905,7 @@ mod tests {
             addr.addr().send(EnvelopeBuffer::Push(envelope.clone()));
         }
 
-        tokio::time::sleep(Duration::from_millis(100)).await;
+        tokio::time::sleep(Duration::from_millis(1100)).await;
 
         assert_eq!(addr.metrics.item_count.load(Ordering::Relaxed), 10);
     }

tests/integration/test_autoscaling.py

@@ -21,7 +21,7 @@ def test_basic_autoscaling_endpoint(mini_sentry, relay):
     response = relay.get("/api/relay/autoscaling/")
     parsed = parse_prometheus(response.text)
     assert response.status_code == 200
-    assert int(parsed["up"]) == 1
+    assert int(parsed["relay_up"]) == 1
 
 
 def test_sqlite_spooling_metrics(mini_sentry, relay):
@@ -49,9 +49,9 @@ def test_sqlite_spooling_metrics(mini_sentry, relay):
     response = relay.get("/api/relay/autoscaling/")
     assert response.status_code == 200
     body = parse_prometheus(response.text)
-    assert int(body["item_count"]) == 200
-    assert int(body["up"]) == 1
-    assert int(body["total_size"]) > 30000
+    assert int(body["relay_spool_item_count"]) == 200
+    assert int(body["relay_up"]) == 1
+    assert int(body["relay_spool_total_size"]) > 30000
 
 
 def test_memory_spooling_metrics(mini_sentry, relay):
@@ -69,6 +69,6 @@ def test_memory_spooling_metrics(mini_sentry, relay):
     response = relay.get("/api/relay/autoscaling/")
     assert response.status_code == 200
     body = parse_prometheus(response.text)
-    assert int(body["item_count"]) == 200
-    assert int(body["up"]) == 1
-    assert int(body["total_size"]) == 0
+    assert int(body["relay_spool_item_count"]) == 200
+    assert int(body["relay_up"]) == 1
+    assert int(body["relay_spool_total_size"]) == 0