fakerabbit's declare_consumer should support more than 1 consumer. also: make fakerabbit Backend.consume be an iterator like it should be..

nova/fakerabbit.py

@@ -77,6 +77,10 @@ class Queue(object):
 
 
 class Backend(base.BaseBackend):
+    def __init__(self, connection, **kwargs):
+        super(Backend, self).__init__(connection, **kwargs)
+        self.consumers = []
+
     def queue_declare(self, queue, **kwargs):
         global QUEUES
         if queue not in QUEUES:
@@ -97,16 +101,20 @@ class Backend(base.BaseBackend):
         EXCHANGES[exchange].bind(QUEUES[queue].push, routing_key)
 
     def declare_consumer(self, queue, callback, *args, **kwargs):
-        self.current_queue = queue
-        self.current_callback = callback
+        self.consumers.append((queue, callback))
 
     def consume(self, limit=None):
+        num = 0
         while True:
-            item = self.get(self.current_queue)
+            for (queue, callback) in self.consumers:
+                item = self.get(queue)
                 if item:
-                self.current_callback(item)
+                    callback(item)
+                    num += 1
+                    yield
+                    if limit and num == limit:
                         raise StopIteration()
-            greenthread.sleep(0)
+            greenthread.sleep(0.1)
 
     def get(self, queue, no_ack=False):
         global QUEUES