Move aggregator into its own repo and add it to the image

util/metrics/prometheus.py

@@ -40,12 +40,12 @@ class PrometheusPlugin(object):
 class Prometheus(object):
   """ Aggregator for collecting stats that are reported to Prometheus. """
   def __init__(self, url=None):
-    self._registered = []
+    self._metric_collectors = []
     self._url = url
 
     if url is not None:
       self._queue = Queue(QUEUE_MAX)
-      self._sender = _QueueSender(self._queue, url, self._registered)
+      self._sender = _QueueSender(self._queue, url, self._metric_collectors)
       self._sender.start()
       logger.debug('Prometheus aggregator sending to %s', url)
     else:
@@ -62,7 +62,7 @@ class Prometheus(object):
     })
 
     if call == 'register':
-      self._registered.append(v)
+      self._metric_collectors.append(v)
       return
 
     try:
@@ -71,7 +71,7 @@ class Prometheus(object):
       # If the queue is full, it is because 1) no aggregator was enabled or 2)
       # the aggregator is taking a long time to respond to requests. In the case
       # of 1, it's probably enterprise mode and we don't care. In the case of 2,
-      # the response timeout error is printed at another place. In either case,
+      # the response timeout error is printed inside the queue handler. In either case,
       # we don't need to print an error here.
       pass
 
@@ -97,13 +97,13 @@ class Prometheus(object):
 class _QueueSender(Thread):
   """ Helper class which uses a thread to asynchronously send metrics to the local Prometheus
       aggregator. """
-  def __init__(self, queue, url, registered):
+  def __init__(self, queue, url, metric_collectors):
     Thread.__init__(self)
     self.daemon = True
     self.next_register = datetime.datetime.now()
     self._queue = queue
     self._url = url
-    self._registered = registered
+    self._metric_collectors = metric_collectors
 
   def run(self):
     while True:
@@ -120,10 +120,10 @@ class _QueueSender(Thread):
       try:
         resp = requests.post(self._url + '/call', '\n'.join(reqs))
         if resp.status_code == 500 and self.next_register <= datetime.datetime.now():
-          resp = requests.post(self._url + '/call', '\n'.join(self._registered))
+          resp = requests.post(self._url + '/call', '\n'.join(self._metric_collectors))
           self.next_register = datetime.datetime.now() + REGISTER_WAIT
           logger.debug('Register returned %s for %s metrics; setting next to %s', resp.status_code,
-                       len(self._registered), self.next_register)
+                       len(self._metric_collectors), self.next_register)
         elif resp.status_code != 200:
           logger.debug('Failed sending to prometheus: %s: %s: %s', resp.status_code, resp.text,
                        ', '.join(reqs))
@@ -135,19 +135,20 @@ class _QueueSender(Thread):
 
 class _Collector(object):
   """ Collector for a Prometheus metric. """
-  def __init__(self, enqueue_method, c_type, name, c_help, namespace='', subsystem='', **kwargs):
+  def __init__(self, enqueue_method, collector_type, collector_name, collector_help,
+               namespace='', subsystem='', **kwargs):
     self._enqueue_method = enqueue_method
 
     self._base_args = {
-      'Name': name,
+      'Name': collector_name,
       'Namespace': namespace,
       'Subsystem': subsystem,
-      'Type': c_type,
+      'Type': collector_type,
     }
 
     registration_params = dict(kwargs)
     registration_params.update(self._base_args)
-    registration_params['Help'] = c_help
+    registration_params['Help'] = collector_help
 
     self._enqueue_method('register', registration_params)