Add more logging to builder_alerts to see why metrics are not reported

infra/services/builder_alerts/crbug_issues.py

 # Copyright 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.
 
 from collections import defaultdict
 import datetime
 import json
+import logging
 
 from apiclient import discovery
 from apiclient.errors import HttpError
 import httplib2
 from oauth2client import client
 
 from infra_libs import ts_mon
 
 
 # Dictionary mapping whitelisted lower-case labels to corresponding tree names.
@@ skipping 27 matching lines @@
   seen_issue_ids = set()
   for whitelisted_label in WHITELISTED_LABELS:
     start_index = 0
     while True:
       request = service.issues().list(
           projectId='chromium', label=whitelisted_label,
           startIndex=start_index, maxResults=BATCH_SIZE, can='open')
       response = request.execute(num_retries=5)
       issue_tracker_requests.increment(
           {'source': 'builder_alerts', 'operation': 'issues_list'})
+      logging.debug('Incremented issue_tracker_requests counter')
   
       # Issue Tracker may omit certain issues occasionally, so counting whether
       # they add up to 'totalResults' in response is not relaible. However, we
       # can use the fact that 'items' is not present in response if we try to
       # list issues starting from an index beyond totalResults.
       if not response.get('items'):
         break
   
       # Here we increment start_index by BATCH_SIZE rather then by the actual
       # number of returned issues in 'items' because as described above, issue
@@ skipping 106 matching lines @@
 
     sheriff_issue['tags'] = sorted(tags)  # converts back to list
     if severity is not None:
       sheriff_issue['severity'] = severity
 
     # We assume that a tags have 1:1 mapping to trees here.
     for tree_name in sheriff_issue['tags']:
       sheriff_issues[tree_name].append(sheriff_issue)
 
   return sheriff_issues