Create Tasks.Tags endpoint and Cron job

appengine/swarming/swarming_rpcs.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 ProtoRPC types for the Swarming Server handlers."""
 
 from protorpc import message_types
 from protorpc import messages
 
 
@@ skipping 284 matching lines @@
   items = messages.MessageField(TaskRequest, 2, repeated=True)
   now = message_types.DateTimeField(3)
 
 
 class TasksCount(messages.Message):
   """Returns the count, as requested."""
   count = messages.IntegerField(1)
   now = message_types.DateTimeField(2)
 
 
+class TasksTags(messages.Message):
+  """Returns all the tags and tag possibilities in the fleet."""
+  tasks_tags = messages.MessageField(StringListPair, 1, repeated=True)
+  # Time at which this summary was calculated.
+  ts = message_types.DateTimeField(2)
+
+
 class TaskRequestMetadata(messages.Message):
   """Provides the ID of the requested TaskRequest."""
   request = messages.MessageField(TaskRequest, 1)
   task_id = messages.StringField(2)
   # Set to finished task result in case task was deduplicated.
   task_result = messages.MessageField(TaskResult, 3)
 
 
 ### Bots
 
@@ skipping 135 matching lines @@
 
 
 class DeletedResponse(messages.Message):
   """Indicates whether a bot was deleted."""
   deleted = messages.BooleanField(1)
 
 
 class TerminateResponse(messages.Message):
   """Returns the pseudo taskid to wait for the bot to shut down."""
   task_id = messages.StringField(1)