[Findit] Use Findit's own versioned config.

appengine/findit/model/wf_config.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.
 
 """Findit for Waterfall configuration."""
 
 from google.appengine.ext import ndb
 
-from components import datastore_utils
+from model.versioned_config import VersionedConfig
 
 
-# TODO(lijeffrey): It seems importing config from luci causes import breakages
-# in other parts of the code. Need to debug and fix the import error and
-# subclass FinditConfig from config.GlobalConfig if possible.
-class FinditConfig(ndb.Model):
-  """Singleton entity with the global configuration of findit."""
-  _config_fetcher = None
-
+class FinditConfig(VersionedConfig):
+  """Global configuration of findit."""
   # A Dict mapping supported masters to lists of unsupported steps.
   masters_to_blacklisted_steps = ndb.JsonProperty(indexed=False, default={})
 
   # Mapping of waterfall builders to try-server trybots, which are used to
   # re-run compile to identify culprits for compile failures.
   builders_to_trybots = ndb.JsonProperty(indexed=False, default={})
-
-  @property
-  def VersionNumber(self):  # pragma: no cover
-    return datastore_utils.HIGH_KEY_ID - self.key.integer_id()
-
-  @classmethod
-  def _get_root_model(cls):  # pragma: no cover
-    return datastore_utils.get_versioned_root_model('%sRoot' % cls.__name__)
-
-  @classmethod
-  def _get_root_key(cls):  # pragma: no cover
-    return ndb.Key(cls._get_root_model(), 1)
-
-  @classmethod
-  def fetch(cls):  # pragma: no cover
-    """Returns the current up-to-date version of the config entity.
-
-    Always fetches it from datastore. May return None if missing.
-    """
-    return datastore_utils.get_versioned_most_recent(cls, cls._get_root_key())
-
-  @classmethod
-  def cached(cls):  # pragma: no cover
-    if not cls._config_fetcher:
-      def config_fetcher():
-        conf = cls.fetch()
-        if not conf:
-          conf = cls()
-          conf.store()
-        return conf
-      cls._config_fetcher = staticmethod(config_fetcher)
-    return cls._config_fetcher()
-
-  def store(self):  # pragma: no cover
-    """Stores a new version of the config entity."""
-    # Create an incomplete key, to be completed by 'store_new_version'.
-    self.key = ndb.Key(self.__class__, None, parent=self._get_root_key())
-    return datastore_utils.store_new_version(self, self._get_root_model())
-
-  def modify(self, **kwargs):  # pragma: no cover
-    """Applies |kwargs| dict to the entity and stores the entity if changed."""
-    dirty = False
-    for k, v in kwargs.iteritems():
-      assert k in self._properties, k
-      if getattr(self, k) != v:
-        setattr(self, k, v)
-        dirty = True
-    if dirty:
-      self.store()
-    return dirty
-
-  # Mapping of waterfall builders to try-server trybots, which are used to
-  # re-run compile to identify culprits for compile failures.
-  builders_to_trybots = ndb.JsonProperty(indexed=False, default={})
-
-
-def Settings():  # pragma: no cover
-  return FinditConfig.cached()
-
-
-def Update(new_config_dict):  # pragma: no cover
-  conf = Settings()
-  conf.modify(**new_config_dict)