buildbucket: support unique change urls

scripts/master/buildbucket/__init__.py

 # Copyright 2015 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.
 
 """buildbucket module implements buildbucket-buildbot integration.
 
 The main entry point is buildbucket.setup() that accepts master configuration
 dict with other buildbucket parameters and configures master to run builds
 scheduled on buildbucket service.
 
 Example:
   buildbucket.setup(
       c,  # Configuration object.
       ActiveMaster,
       buckets=['qo'],
   )
 
 """
 
 import functools
 import os
 import sys
 
 from .common import Error
 from .integration import BuildBucketIntegrator, MAX_MAX_BUILDS
 from .poller import BuildBucketPoller
 from .status import BuildBucketStatus
+from . import changestore
 from . import client
 from . import trigger
 
 
 NO_LEASE_LIMIT = sys.maxint
 
 
 def setup(
     config, active_master, buckets, build_params_hook=None,
     poll_interval=10, buildbucket_hostname=None, max_lease_count=None,
-    verbose=None, dry_run=None):
+    verbose=None, dry_run=None, unique_change_urls=False):
   """Configures a master to lease, schedule and update builds on buildbucket.
 
   Requires config to have 'mergeRequests' set to False.
 
   Args:
     config (dict): master configuration dict.
     active_master (config.Master.Base): master site config.
     buckets (list of str): a list of buckets to poll.
     build_params_hook: callable with arguments (params, build) that can modify
       parameters (and properties via parameters['properties']) before creating
       a buildset during validation.
         params: dict name->value
         build: dict describing a buildbucket build.
 
       If a ValueError is raised, the build will be marked as an
       INVALID_BUILD_DEFINITION failure and the error message will be propagated
       to the BuildBucket status.
     poll_interval (int): frequency of polling, in seconds. Defaults to 10.
     buildbucket_hostname (str): if not None, override the default buildbucket
       service url.
     max_lease_count (int): maximum number of builds that can be leased at a
       time. Defaults to the number of connected slaves.
     verbose (bool): log more than usual. Defaults to False.
     dry_run (bool): whether to run buildbucket in a dry-run mode.
+    unique_change_urls (bool): if True, change URLs in builds are treated as
+      change identifiers. This is True on waterfalls and typically False on
+      tryservers.
 
   Raises:
     buildbucket.Error if config['mergeRequests'] is not False.
   """
   assert isinstance(config, dict), 'config must be a dict'
   assert active_master
   assert active_master.service_account_path, 'Service account is not assigned'
   assert buckets, 'Buckets are not specified'
   assert isinstance(buckets, list), 'Buckets must be a list'
   assert all(isinstance(b, basestring) for b in buckets), (
         'all buckets must be strings')
 
   if dry_run is None:
     dry_run = 'POLLER_DRY_RUN' in os.environ
 
   integrator = BuildBucketIntegrator(
       buckets, build_params_hook=build_params_hook,
-      max_lease_count=max_lease_count)
+      max_lease_count=max_lease_count,
+      change_store_factory=lambda bb: changestore.ChangeStore(
+          bb, unique_urls=unique_change_urls))
 
   buildbucket_service = client.create_buildbucket_service(
       active_master, buildbucket_hostname, verbose)
 
   poller = BuildBucketPoller(
       integrator=integrator,
       poll_interval=poll_interval,
       dry_run=dry_run)
   status = BuildBucketStatus(
       integrator,
       buildbucket_service,
       dry_run=dry_run)
   config.setdefault('change_source', []).append(poller)
   config.setdefault('status', []).append(status)