Rewrote arbitrary data cache system

The caching facilities in Bcfg2.Server.Cache provided basically no
features.  This rewrites that to allow for much more powerful cache
expiration, with a particular focus on interoperation between
different components and plugins to let caches be expired as
necessary.  (E.g., the Probes plugin can expire the Metadata cache.)

This does not affect any of the file data cached by Bcfg2, only the
caches that are populated with arbitrary data (Metadata, Packages,
Probes, etc.).

1 files changed, 7 insertions, 11 deletions

diff --git a/src/lib/Bcfg2/Server/Plugins/Metadata.py b/src/lib/Bcfg2/Server/Plugins/Metadata.py
index 3a470b8de..75cf6454c 100644
--- a/src/lib/Bcfg2/Server/Plugins/Metadata.py
+++ b/src/lib/Bcfg2/Server/Plugins/Metadata.py
@@ -17,10 +17,10 @@ import Bcfg2.Options
 import Bcfg2.Server.Plugin
 import Bcfg2.Server.FileMonitor
 from Bcfg2.Utils import locked
+from Bcfg2.Server.Cache import Cache
 from Bcfg2.Compat import MutableMapping, all, wraps  # pylint: disable=W0622
 from Bcfg2.version import Bcfg2VersionInfo
 
-
 # pylint: disable=C0103
 ClientVersions = None
 MetadataClientModel = None
@@ -90,7 +90,7 @@ def load_django_models():
 
         def keys(self):
             """ Get keys for the mapping """
-            return [c.hostname for c in MetadataClientModel.objects.all()]
+            return list(iter(self))
 
         def __contains__(self, key):
             try:
@@ -513,7 +513,6 @@ class MetadataGroup(tuple):  # pylint: disable=E0012,R0924
 
 
 class Metadata(Bcfg2.Server.Plugin.Metadata,
-               Bcfg2.Server.Plugin.Caching,
                Bcfg2.Server.Plugin.ClientRunHooks,
                Bcfg2.Server.Plugin.DatabaseBacked):
     """This class contains data for bcfg2 server metadata."""
@@ -533,7 +532,6 @@ class Metadata(Bcfg2.Server.Plugin.Metadata,
 
     def __init__(self, core, datastore, watch_clients=True):
         Bcfg2.Server.Plugin.Metadata.__init__(self)
-        Bcfg2.Server.Plugin.Caching.__init__(self)
         Bcfg2.Server.Plugin.ClientRunHooks.__init__(self)
         Bcfg2.Server.Plugin.DatabaseBacked.__init__(self, core, datastore)
         self.watch_clients = watch_clients
@@ -578,6 +576,7 @@ class Metadata(Bcfg2.Server.Plugin.Metadata,
             self.versions = dict()
         self.uuid = {}
         self.session_cache = {}
+        self.cache = Cache("Metadata")
         self.default = None
         self.pdirty = False
         self.password = Bcfg2.Options.setup.password
@@ -977,16 +976,13 @@ class Metadata(Bcfg2.Server.Plugin.Metadata,
                     self.groups[gname]
         self.states['groups.xml'] = True
 
-    def expire_cache(self, key=None):
-        self.core.metadata_cache.expire(key)
-
     def HandleEvent(self, event):
         """Handle update events for data files."""
         for handles, event_handler in self.handlers.items():
             if handles(event):
                 # clear the entire cache when we get an event for any
                 # metadata file
-                self.expire_cache()
+                self.cache.expire()
                 event_handler(event)
 
         if False not in list(self.states.values()) and self.debug_flag:
@@ -1147,8 +1143,8 @@ class Metadata(Bcfg2.Server.Plugin.Metadata,
             raise Bcfg2.Server.Plugin.MetadataRuntimeError("Metadata has not "
                                                            "been read yet")
         client = client.lower()
-        if client in self.core.metadata_cache:
-            return self.core.metadata_cache[client]
+        if client in self.cache:
+            return self.cache[client]
 
         if client in self.aliases:
             client = self.aliases[client]
@@ -1243,7 +1239,7 @@ class Metadata(Bcfg2.Server.Plugin.Metadata,
                             addresses, categories, uuid, password, version,
                             self.query)
         if self.core.metadata_cache_mode == 'initial':
-            self.core.metadata_cache[client] = rv
+            self.cache[client] = rv
         return rv
 
     def get_all_group_names(self):