Docserver: Persist stat cache for versioned file systems

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

 # Copyright 2014 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 traceback
 
 from app_yaml_helper import AppYamlHelper
 from appengine_wrappers import IsDeadlineExceededError, logservice
 from branch_utility import BranchUtility
 from compiled_file_system import CompiledFileSystem
 from custom_logger import CustomLogger
 from data_source_registry import CreateDataSource
 from environment import GetAppVersion
 from file_system import IsFileSystemThrottledError
 from future import Future
 from gcs_file_system_provider import CloudStorageFileSystemProvider
 from github_file_system_provider import GithubFileSystemProvider
 from host_file_system_provider import HostFileSystemProvider
 from object_store_creator import ObjectStoreCreator
 from server_instance import ServerInstance
 from servlet import Servlet, Request, Response
 from timer import Timer, TimerClosure
 
 
 
 _log = CustomLogger('refresh')
 
 
+
+class _InstanceMasterCommitUpdater(object):
+  def __init__(self, commit):
+    self._commit = commit
+
+  def Refresh(self, path):
+    if self._commit is None:
+      raise ValueError('Refusing to set instance master without a commit ID')
+    creator = ObjectStoreCreator(start_empty=False)
+    store = creator.Create(str, category='commits')

[not at google - send to devlin, 2014/10/20 21:06:58]

Ok - I see why you use str. Maybe you should pull this "master commit thing"
into its own class (or at least own file) which does its own caching.

[Ken Rockot(use gerrit already), 2014/10/22 03:19:54]

Done.

+    store.SetMulti({ 'master': self._commit })
+    return Future(callback=lambda: None)
+
+
+
 class RefreshServlet(Servlet):
   '''Servlet which refreshes a single data source.
   '''
   def __init__(self, request, delegate_for_test=None):
     Servlet.__init__(self, request)
     self._delegate = delegate_for_test or RefreshServlet.Delegate()
 
   class Delegate(object):
     '''RefreshServlet's runtime dependencies. Override for testing.
     '''
@@ skipping 46 matching lines @@
                    'This is probably NOT what you want.')
       commit = None
 
     server_instance = self._CreateServerInstance(commit)
     success = True
     try:
       if source_name == 'platform_bundle':
         data_source = server_instance.platform_bundle
       elif source_name == 'content_providers':
         data_source = server_instance.content_providers
+      elif source_name == 'instance_master':
+        data_source = _InstanceMasterCommitUpdater(commit)
       else:
         data_source = CreateDataSource(source_name, server_instance)
 
       class_name = data_source.__class__.__name__
       refresh_future = data_source.Refresh(source_path)
       assert isinstance(refresh_future, Future), (
           '%s.Refresh() did not return a Future' % class_name)
       timer = Timer()
       try:
         refresh_future.Get()
@@ skipping 29 matching lines @@
     github_file_system_provider = self._delegate.CreateGithubFileSystemProvider(
         object_store_creator)
     gcs_file_system_provider = self._delegate.CreateGCSFileSystemProvider(
         object_store_creator)
     return ServerInstance(object_store_creator,
                           CompiledFileSystem.Factory(object_store_creator),
                           branch_utility,
                           host_file_system_provider,
                           github_file_system_provider,
                           gcs_file_system_provider)