make version of ts_mon compatible with appengine

appengine_module/gae_ts_mon/monitoring.py

+#!/usr/bin/env python
+# Copyright (c) 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Send system monitoring data to the timeseries monitoring API."""
+
+import logging
+import webapp2
+
+from common.metrics import *
+import config
+import interface
+
+from google.appengine.api import app_identity
+from google.appengine.api import modules
+
+import os
+import sys
+
+
+access_count = CounterMetric('gae/access/count')
+request_bytes = CumulativeDistributionMetric('http/request_bytes')
+response_bytes = CumulativeDistributionMetric('http/response_bytes')
+durations = CumulativeDistributionMetric('http/durations')
+response_status = CounterMetric('http/response_status')
+
+
+class InitializeMonitoringHandler(webapp2.RequestHandler):
+
+  def get(self):
+    service = app_identity.get_application_id()
+    version = modules.get_current_version_name()
+    instance_id = int(modules.get_current_instance_id())
+    endpoint = 'pubsub://chrome-infra-mon-pubsub/monacq'

[Sergey Berezin, 2015/08/18 00:40:38]

nit: in general, it's a bad idea to hard-code endpoints. At the very least,
let's make it into a constant and define at the top of the file, for visibility.

+    config.initialize(job_name=version, instance=instance_id,
+                      service_name=service, endpoint=endpoint)
+    self.response.set_status(200, 'Initialized instance of ts_mon.')
+
+
+class MonitoringHandler(webapp2.RequestHandler):
+
+  ''' Called by cron jobs every 5 minutes to update metrics. '''
+  def get(self, key=None):
+    interface.flush()
+    self.response.write('Metrics updated.')

[Sergey Berezin, 2015/08/18 00:40:38]

nit: change it to logging.info(). Response will likely be lost in a cron job.

+    return
+
+
+app = webapp2.WSGIApplication([
+    ('/_ah/start', InitializeMonitoringHandler),
+    ('/monitoring', MonitoringHandler),
+    ('/monitoring/(.*)', MonitoringHandler)
+], debug=True)