Docserver: Add _query_commit handler

chrome/common/extensions/docs/server2/handler.py

 # Copyright (c) 2012 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.
 
 import time
 
 from appengine_wrappers import taskqueue
+from commit_tracker import CommitTracker
 from cron_servlet import CronServlet
 from instance_servlet import InstanceServlet
+from object_store_creator import ObjectStoreCreator
 from patch_servlet import PatchServlet
 from refresh_servlet import RefreshServlet
 from servlet import Servlet, Request, Response
 from test_servlet import TestServlet
 
 
 _DEFAULT_SERVLET = InstanceServlet.GetConstructor()
 
 
-_FORCE_CRON_TARGET = 'force_cron'
+class _EnqueueServlet(Servlet):
+  '''This Servlet can be used to manually enqueue tasks on the default
+  taskqueue. Useful for when an admin wants to manually force a specific
+  DataSource refresh, but the refresh operation takes longer than the 60 sec
+  timeout of a non-taskqueue request. For example, you might query
+
+  /_enqueue/_refresh/content_providers/cr-native-client?commit=123ff65468dcafff0
+
+  which will enqueue a task (/_refresh/content_providers/cr-native-client) to
+  refresh the NaCl documentation cache for commit 123ff65468dcafff0.
+
+  Access to this servlet should always be restricted to administrative users.
+  '''
+  def __init__(self, request):
+    Servlet.__init__(self, request)
+
+  def Get(self):
+    queue = taskqueue.Queue()
+    queue.add(taskqueue.Task(url='/%s' % self._request.path,
+                             params=self._request.arguments))
+    return Response.Ok('Task enqueued.')
+
+
+class _QueryCommitServlet(Servlet):
+  '''Provides read access to the commit ID cache within the server. For example:
+
+  /_query_commit/master
+
+  will return the commit ID stored under the commit key "master" within the
+  commit cache. Currently "master" is the only named commit we cache, and it
+  corresponds to the commit ID whose data currently populates the data cache
+  used by live instances.
+  '''
+  def __init__(self, request):
+    Servlet.__init__(self, request)
+
+  def Get(self):
+    object_store_creator = ObjectStoreCreator(start_empty=False)
+    commit_tracker = CommitTracker(object_store_creator)
+    return Response.Ok(commit_tracker.Get(self._request.path).Get())
 
 
 _SERVLETS = {
   'cron': CronServlet,
+  'enqueue': _EnqueueServlet,
   'patch': PatchServlet,
+  'query_commit': _QueryCommitServlet,
   'refresh': RefreshServlet,
   'test': TestServlet,
 }
 
 
 class Handler(Servlet):
   def Get(self):
     path = self._request.path
 
     if path.startswith('_'):
       servlet_path = path[1:]
       if not '/' in servlet_path:
         servlet_path += '/'
       servlet_name, servlet_path = servlet_path.split('/', 1)
-      if servlet_name == _FORCE_CRON_TARGET:
-        queue = taskqueue.Queue()
-        queue.purge()
-        time.sleep(2)
-        queue.add(taskqueue.Task(url='/_cron'))
-        return Response.Ok('Cron job started.')
-      if servlet_name == 'enqueue':
-        queue = taskqueue.Queue()
-        queue.add(taskqueue.Task(url='/%s'%servlet_path))
-        return Response.Ok('Task enqueued.')
       servlet = _SERVLETS.get(servlet_name)
       if servlet is None:
         return Response.NotFound('"%s" servlet not found' %  servlet_path)
     else:
       servlet_path = path
       servlet = _DEFAULT_SERVLET
 
     return servlet(Request(servlet_path,
                            self._request.host,
                            self._request.headers,
                            self._request.arguments)).Get()