Docserver: Add commit history and _reset_commit servlet

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

-# Copyright (c) 2012 The Chromium Authors. All rights reserved.
+# 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 time
-
 from appengine_wrappers import taskqueue
 from commit_tracker import CommitTracker
-from cron_servlet import CronServlet
-from instance_servlet import InstanceServlet
+from future import All
 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
+from servlet import Servlet, Response
 
 
-_DEFAULT_SERVLET = InstanceServlet.GetConstructor()
-
-
-class _EnqueueServlet(Servlet):
+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):
+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())
+
+    def generate_response(result):
+      commit_id, history = result
+      history_log = ''.join('%s: %s<br>' % (entry.datetime, entry.commit_id)
+                            for entry in reversed(history))
+      response = 'Current commit: %s<br><br>Most recent commits:<br>%s' % (
+          commit_id, history_log)
+      return response
+
+    commit_name = self._request.path
+    id_future = commit_tracker.Get(commit_name)
+    history_future = commit_tracker.GetHistory(commit_name)
+    return Response.Ok(
+        All((id_future, history_future)).Then(generate_response).Get())
 
 
-_SERVLETS = {
-  'cron': CronServlet,
-  'enqueue': _EnqueueServlet,
-  'patch': PatchServlet,
-  'query_commit': _QueryCommitServlet,
-  'refresh': RefreshServlet,
-  'test': TestServlet,
-}
+class ResetCommitServlet(Servlet):
+  '''Writes a new commit ID to the commit cache. For example:
 
+  /_reset_commit/master/123456
 
-class Handler(Servlet):
+  will reset the 'master' commit ID to '123456'. The provided commit MUST be
+  in the named commit's recent history or it will be ignored.
+  '''
+  def __init__(self, request):
+    Servlet.__init__(self, request)
+
   def Get(self):
-    path = self._request.path
+    object_store_creator = ObjectStoreCreator(start_empty=False)
+    commit_tracker = CommitTracker(object_store_creator)
+    commit_name, commit_id = self._request.path.split('/')

[not at google - send to devlin, 2014/11/19 19:32:41]

You might want to use .split('/', 1) so that this doesn't crash if there are
more than 1 '/' tokens.

You might also consider using one of the utilities in path.py. I think that has
something which does that, and either way, they make nice assertions about valid
paths.

[Ken Rockot(use gerrit already), 2015/02/02 23:57:44]

Done.

+    history = commit_tracker.GetHistory(commit_name).Get()
+    if not any(entry.commit_id == commit_id for entry in history):
+      return Response.NotFound('Commit %s not found.' % commit_id)

[not at google - send to devlin, 2014/11/19 19:32:41]

Nit, but I don't think 404 is actually the right error code here. Maybe 400 (bad
request)? Or something else you find in
http://en.wikipedia.org/wiki/List_of_HTTP_status_codes#4xx_Client_Error which
sounds right.

Of course, you should add a BadRequest (or whatever) utility to Response if you
go with that.

[Ken Rockot(use gerrit already), 2015/02/02 23:57:44]

Done. 400 seems like the only reasonable option.

+    commit_tracker.Set(commit_name, commit_id).Get()
+    return Response.Ok('Commit "%s" updated to %s' % (commit_name, commit_id))
 
-    if path.startswith('_'):
-      servlet_path = path[1:]
-      if not '/' in servlet_path:
-        servlet_path += '/'
-      servlet_name, servlet_path = servlet_path.split('/', 1)
-      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()