buildbucket: support unique change urls

scripts/master/buildbucket/changestore.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.
 
 """ChangeStore maps buildbucket changes to Buildbot changes."""
 
 from master.buildbucket import common
 from twisted.internet import defer
 
 
-CHANGE_CACHE_NAME = 'buildbucket_changes'
-
-
 class ChangeStore(object):
   """Maps buildbucket changes to Buildbot changes."""
 
-  def __init__(self, buildbot_gateway):
+  def __init__(self, buildbot_gateway, unique_urls=False):
+    """Initializes a ChangeStore.
+
+    If unique_urls is True, treats change's non-empty url as change identifier.
+    It should be False on Rietveld-based tryservers because url may mean base
+    revision where a Rietveld patchset must be applied to.
+    """
     assert buildbot_gateway
     self.buildbot = buildbot_gateway
-    self._find_change_cache = self.buildbot.get_cache(
-        CHANGE_CACHE_NAME,
-        self._find_change_in_db
+    self.unique_urls = unique_urls
+    self._find_change_cache_by_id = self.buildbot.get_cache(
+        'buildbucket_changes',
+        self._find_change_in_db_by_id,
+    )
+    self._find_change_cache_by_revlink = self.buildbot.get_cache(
+        'buildbucket_changes_revlink',
+        self._find_change_in_db_by_revlink,
     )
 
   def _insert_change(self, buildbucket_change):
     """Inserts a new Change object to the buildbot.
 
     Args:
       buildbucket_change (dict): a change described in build parameters.
 
     Returns:
       Buildbot change id as Deferred.
@@ skipping 17 matching lines @@
         category=common.CHANGE_CATEGORY,
         revlink=buildbucket_change.get('url') or '',
         properties={
             common.INFO_PROPERTY: (info, 'Change'),
         },
         repository=buildbucket_change.get('repo_url') or '',
         project=buildbucket_change.get('project') or '',
     )
 
   @defer.inlineCallbacks
-  def _find_change_in_db(self, revision_and_id):
+  def _find_change_in_db_by_id(self, revision_and_id):
     """Searches for an existing Change object in the database.
 
     Args:
       revision_and_id: a tuple of change revision and buildbucket-level change
         id.
 
     Every Change object has a revision attribute. The buildbucket-level change
     id is stored as common.INFO_PROPERTY/common.BUILDBUCKET_CHANGE_ID_PROPERTY
     property.
 
@@ skipping 10 matching lines @@
     for buildbot_change_id in buildbot_change_ids:
       change = yield self.buildbot.get_change_by_id(buildbot_change_id)
       info = change.properties.getProperty(common.INFO_PROPERTY)
       if info is None:
         continue
       prop_value = info.get(common.BUILDBUCKET_CHANGE_ID_PROPERTY)
       if str(prop_value) == str(buildbucket_change_id):
         defer.returnValue(change)
         return
 
-  def _find_change(self, revision, buildbucket_change_id):
-    """Searches for a Change by revision and change_key. Uses cache."""
-    assert revision
-    assert buildbucket_change_id
-    # Use (revision, buildbucket_change_id) tuple as cache key.
-    return self._find_change_cache.get((revision, buildbucket_change_id))
+  @defer.inlineCallbacks
+  def _find_change_in_db_by_revlink(self, revlink):
+    """Searches for one Change object by revlink in the database.
+
+    Returns:
+      buildbot.changes.change.Change object as Deferred.
+    """
+    buildbot_change_ids = yield self.buildbot.find_changes_by_revlink(revlink)
+    if buildbot_change_ids:
+      change = yield self.buildbot.get_change_by_id(buildbot_change_ids[0])
+      defer.returnValue(change)
 
   @defer.inlineCallbacks
   def get_change(self, buildbucket_change):
     """Returns an existing or new Buildbot Change for a buildbucket change.
 
     Args:
       buildbucket_change (dict): a change found in build parameters.
 
     Returns:
       buildbot.changes.change.Change object as Deferred.
     """
     buildbot_change = None
 
-    if buildbucket_change.get('revision') and buildbucket_change.get('id'):
-      buildbot_change = yield self._find_change(
-          buildbucket_change['revision'], buildbucket_change['id'])
+    if self.unique_urls and buildbucket_change.get('url'):
+      buildbot_change = yield self._find_change_cache_by_revlink.get(
+          buildbucket_change.get('url'))
+    elif buildbucket_change.get('revision') and buildbucket_change.get('id'):
+      buildbot_change = yield self._find_change_cache_by_id.get(
+          (buildbucket_change['revision'], buildbucket_change['id']))
 
     if buildbot_change is None:
       change_id = yield self._insert_change(buildbucket_change)
       buildbot_change = yield self.buildbot.get_change_by_id(change_id)
     defer.returnValue(buildbot_change)
 
   @defer.inlineCallbacks
   def _insert_source_stamp(self, buildbucket_changes):
     """Inserts a new SourceStamp for the list of changes and returns ssid."""
     assert isinstance(buildbucket_changes, list)
@@ skipping 32 matching lines @@
     if cache is not None and all('id' in c for c in buildbucket_changes):
       cache_key = tuple(sorted([c['id'] for c in buildbucket_changes]))
       ssid = cache.get(cache_key)
       if ssid:
         defer.returnValue(ssid)
         return
     ssid = yield self._insert_source_stamp(buildbucket_changes)
     if cache is not None:
       cache[cache_key] = ssid
     defer.returnValue(ssid)