Add caching for task counts

appengine/swarming/handlers_endpoints.py

 # Copyright 2015 The LUCI Authors. All rights reserved.
 # Use of this source code is governed under the Apache License, Version 2.0
 # that can be found in the LICENSE file.
 
 """This module defines Swarming Server endpoints handlers."""
 
 import logging
 import os
 
 from google.appengine.api import datastore_errors
+from google.appengine.api import memcache as gae_memcache

[M-A Ruel, 2017/02/16 18:15:19]

why rename?

[kjlubick, 2017/02/17 15:54:49]

It was to be consistent with components/utils.py.  I'll un-rename it.

 from google.appengine.ext import ndb
+
 import endpoints
 import gae_ts_mon
 from protorpc import messages
 from protorpc import message_types
 from protorpc import protojson
 from protorpc import remote
 
 from components import auth
 from components import datastore_utils
 from components import endpoints_webapp2
@@ skipping 481 matching lines @@
   @auth.endpoints_method(
       swarming_rpcs.TasksCountRequest, swarming_rpcs.TasksCount,
       http_method='GET')
   @auth.require(acl.is_privileged_user)
   def count(self, request):
     """Counts number of tasks in a given state."""
     logging.info('%s', request)
     if not request.start:
       raise endpoints.BadRequestException('start (as epoch) is required')
     now = utils.utcnow()
+    mem_key = self._memcache_key(request, now)
+    count = gae_memcache.get(mem_key)

[M-A Ruel, 2017/02/16 18:15:19]

use a namespace, e.g. 'tasks_count'

+    if count is not None:
+      return swarming_rpcs.TasksCount(count=count, now=now)
+
     try:
       count = self._query_from_request(request, 'created_ts').count()
+      gae_memcache.add(mem_key, count, 120)

[M-A Ruel, 2017/02/16 18:15:19]

technically the entry is valid for a while since you encode the end time, you
could use 24*60*60 as the expiration.

[kjlubick, 2017/02/17 15:54:49]

Done

     except ValueError as e:
       raise endpoints.BadRequestException(
           'Inappropriate filter for tasks/count: %s' % e)
     return swarming_rpcs.TasksCount(count=count, now=now)
 
+  def _memcache_key(self, request, now):
+    # Floor now to minute to account for empty "end"
+    end = request.end or now.replace(second=0, microsecond=0)
+    request.tags.sort()
+    return '%s|%s|%s|%s' % (request.tags, request.state, request.start, end)
+
   def _query_from_request(self, request, sort=None):
     """Returns a TaskResultSummary query."""
     start = message_conversion.epoch_to_datetime(request.start)
     end = message_conversion.epoch_to_datetime(request.end)
     return task_result.get_result_summaries_query(
         start, end,
         sort or request.sort.name.lower(),
         request.state.name.lower(),
         request.tags)
 
@@ skipping 289 matching lines @@
 def get_routes():
   return (
     endpoints_webapp2.api_routes(SwarmingServerService) +
     endpoints_webapp2.api_routes(SwarmingTaskService) +
     endpoints_webapp2.api_routes(SwarmingTasksService) +
     endpoints_webapp2.api_routes(SwarmingBotService) +
     endpoints_webapp2.api_routes(SwarmingBotsService) +
     # components.config endpoints for validation and configuring of luci-config
     # service URL.
     endpoints_webapp2.api_routes(config.ConfigApi))