More robust support for Redis configuration in web socket server

.travis.requirements

@@ -4,3 +4,4 @@ requests
 flask
 redis
 python-dateutil
+websockets

platypush/backend/http/__init__.py

@@ -116,9 +116,12 @@ class HttpBackend(Backend):
     def _get_redis(self):
         redis_backend = get_backend('redis')
         if not redis_backend:
-            raise RuntimeError('Redis backend not configured')
+            self.logger.warning('Redis backend not configured - some ' +
+                                'web server features may not be working properly')
+            redis_args = {}
+        else:
+            redis_args = redis_backend.redis_args
 
-        redis_args = get_backend('redis').redis_args
         redis = Redis(**redis_args)
         return redis
 

platypush/context/__init__.py

@@ -56,7 +56,7 @@ def get_backend(name):
     """ Returns the backend instance identified by name if it exists """
 
     global backends
-    return backends[name]
+    return backends.get('name')
 
 
 def get_plugin(plugin_name, reload=False):

tests/etc/config.yaml

@@ -1,6 +1,3 @@
-backend.redis:
-    disabled: False
-
 backend.http:
     port: 8123
     disable_websocket: True