[Findit] Integrate with Fracas through Pub/Sub.

appengine/findit/common/pubsub_util.py

+# Copyright 2016 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 base64
+
+import httplib2
+from googleapiclient import discovery
+from oauth2client import client as oauth2client
+
+
+PUBSUB_SCOPES = [
+    'https://www.googleapis.com/auth/pubsub',
+]
+
+
+def CreatePubSubClient():  # pragma: no cover.
+  credentials = oauth2client.GoogleCredentials.get_application_default()
+  if credentials.create_scoped_required():
+    credentials = credentials.create_scoped(PUBSUB_SCOPES)
+  http = httplib2.Http()
+  credentials.authorize(http)
+  return discovery.build('pubsub', 'v1', http=http)
+
+
+def PublishMessagesToTopic(messages_data, topic):  # pragma: no cover.
+  messages = []
+  for message_data in messages_data:
+    messages.append({'data': base64.b64encode(message_data)})
+  return CreatePubSubClient().projects().topics().publish(
+      topic=topic, body={'messages': messages}).execute()