cache-force-backend.diff

diff --git a/indico/MaKaC/common/cache.py b/indico/MaKaC/common/cache.py
index dfce4ff..d4203f8 100644
--- a/indico/MaKaC/common/cache.py
+++ b/indico/MaKaC/common/cache.py
@@ -471,13 +471,28 @@ class FileCacheClient(CacheClient):
 
 
 class GenericCache(object):
-    def __init__(self, namespace):
+    def __init__(self, namespace, force_backend=None):
         self._client = None
         self._namespace = namespace
 
+        if force_backend:
+            self._client = self._select_backend(force_backend)
+
     def __repr__(self):
         return 'GenericCache(%r)' % self._namespace
 
+    def _select_backend(self, backend):
+        # If not, create a new one
+        if backend == 'memcached':
+            import memcache
+            return memcache.Client(Config.getInstance().getMemcachedServers())
+        elif backend == 'redis':
+            return RedisCacheClient(Config.getInstance().getRedisCacheURL())
+        elif backend == 'files':
+            return FileCacheClient(Config.getInstance().getXMLCacheDir())
+        else:
+            return NullCacheClient()
+
     def _connect(self):
         # Maybe we already have a client in this instance
         if self._client is not None:
@@ -488,17 +503,7 @@ class GenericCache(object):
         if self._client is not None:
             return
 
-        # If not, create a new one
-        backend = Config.getInstance().getCacheBackend()
-        if backend == 'memcached':
-            import memcache
-            self._client = memcache.Client(Config.getInstance().getMemcachedServers())
-        elif backend == 'redis':
-            self._client = RedisCacheClient(Config.getInstance().getRedisCacheURL())
-        elif backend == 'files':
-            self._client = FileCacheClient(Config.getInstance().getXMLCacheDir())
-        else:
-            self._client = NullCacheClient()
+        self._client = self._select_backend(Config.getInstance().getCacheBackend())
 
         ContextManager.set('GenericCacheClient', self._client)