Add prometheus metric for queued builds

endpoints/building.py

@@ -5,7 +5,7 @@ from datetime import datetime, timedelta
 
 from flask import request
 
-from app import app, dockerfile_build_queue
+from app import app, dockerfile_build_queue, metric_queue
 from data import model
 from data.database import db
 from auth.auth_context import get_authenticated_user
@@ -82,6 +82,10 @@ def start_build(repository, prepared_build, pull_robot_name=None):
     build_request.queue_id = queue_id
     build_request.save()
 
+  # Add the queueing of the build to the metrics queue.
+  metric_queue.repository_build_queued.Inc(labelvalues=[repository.namespace_user.username,
+                                                        repository.name])
+
   # Add the build to the repo's log and spawn the build_queued notification.
   event_log_metadata = {
     'build_id': build_request.uuid,

util/metrics/metricqueue.py

@@ -74,6 +74,10 @@ class MetricQueue(object):
                                                labelnames=['namespace', 'repo_name', 'protocol',
                                                            'status'])
 
+    self.repository_build_queued = prom.create_counter('repository_build_queued',
+                                                       'Repository Build Queued Count',
+                                                       labelnames=['namespace', 'repo_name'])
+
     self.repository_build_completed = prom.create_counter('repository_build_completed',
                                                           'Repository Build Complete Count',
                                                           labelnames=['namespace', 'repo_name',