Add a configurable prometheus namespace for all metrics

Fixes #1918

config.py

@@ -369,6 +369,9 @@ class DefaultConfig(object):
   # URL that specifies the location of the prometheus stats aggregator.
   PROMETHEUS_AGGREGATOR_URL = 'http://localhost:9092'
 
+  # Namespace prefix for all prometheus metrics.
+  PROMETHEUS_NAMESPACE = 'quay'
+
   # Reverse DNS prefixes that are reserved for internal use on labels and should not be allowable
   # to be set via the API.
   DEFAULT_LABEL_KEY_RESERVED_PREFIXES = ['com.docker.', 'io.docker.', 'org.dockerproject.',

util/metrics/prometheus.py

@@ -25,8 +25,9 @@ class PrometheusPlugin(object):
 
   def init_app(self, app):
     prom_url = app.config.get('PROMETHEUS_AGGREGATOR_URL')
+    prom_namespace = app.config.get('PROMETHEUS_NAMESPACE')
     logger.debug('Initializing prometheus with aggregator url: %s', prom_url)
-    prometheus = Prometheus(prom_url)
+    prometheus = Prometheus(prom_url, prom_namespace)
 
     # register extension with app
     app.extensions = getattr(app, 'extensions', {})
@@ -39,9 +40,10 @@ class PrometheusPlugin(object):
 
 class Prometheus(object):
   """ Aggregator for collecting stats that are reported to Prometheus. """
-  def __init__(self, url=None):
+  def __init__(self, url=None, namespace=None):
     self._metric_collectors = []
     self._url = url
+    self._namespace = namespace or ''
 
     if url is not None:
       self._queue = Queue(QUEUE_MAX)
@@ -91,6 +93,7 @@ class Prometheus(object):
     return self._create_collector('Untyped', args, kwargs)
 
   def _create_collector(self, collector_type, args, kwargs):
+    kwargs['namespace'] = kwargs.get('namespace', self._namespace)
     return _Collector(self.enqueue, collector_type, *args, **kwargs)
 
 
@@ -138,7 +141,6 @@ class _Collector(object):
   def __init__(self, enqueue_method, collector_type, collector_name, collector_help,
                namespace='', subsystem='', **kwargs):
     self._enqueue_method = enqueue_method
-
     self._base_args = {
       'Name': collector_name,
       'Namespace': namespace,