fix bug in MetaListener

pilab/events/meta.py

@@ -81,19 +81,23 @@ class Event(BaseModel):
 
 
 class MetaListener(threading.Thread):
-    def __init__(self, callback: Callable, queue: str = STREAM_NAME, offset = "last"):
+    def __init__(self, callback: Callable, queue: str = STREAM_NAME, offset="first"):
         super(MetaListener, self).__init__()
         self.queue: str = queue
         self.callback: Callable = callback
-        self.arguments = {"x-stream-offset": offset}
+        self.offset = offset
         self.channel = None
         self.connection = None
 
+        self._prefetch_count = 2
+
     def default_callback(self, ch, method, properties, body):
         try:
             event = Event.parse_obj(json.loads(body.decode('utf-8')))
-            self.callback(event)
+            offset = properties.headers['x-stream-offset']
+            self.callback(event, offset)
             ch.basic_ack(delivery_tag=method.delivery_tag)
+            self.offset = offset
             logger.info(f"Event processed succesful")
         except Exception as e:
             traceback.print_exc()
@@ -104,8 +108,12 @@ class MetaListener(threading.Thread):
             try:
                 self.connection = utils.get_blocking_connection()
                 self.channel = self.connection.channel()
-                self.channel.queue_declare(queue=self.queue, durable=True, exclusive=False, auto_delete=False, arguments={"x-queue-type": "stream"})
-                self.channel.basic_consume(queue=self.queue, on_message_callback=self.default_callback, auto_ack=False, arguments=self.arguments)
+                self.channel.queue_declare(queue=self.queue, durable=True, exclusive=False, auto_delete=False,
+                                           arguments={"x-queue-type": "stream"})
+                self.channel.basic_qos(prefetch_count=self._prefetch_count)
+                self.channel.basic_consume(queue=self.queue, on_message_callback=self.default_callback, auto_ack=False,
+                                           arguments={"x-stream-offset": self.offset})
+
                 try:
                     self.channel.start_consuming()
                 except SystemExit:
@@ -126,3 +134,4 @@ class MetaListener(threading.Thread):
                 logger.error(f"Connection closed unexpected, retrying...")
                 time.sleep(1)
                 continue
+

setup.py

@@ -2,7 +2,7 @@ from setuptools import setup, find_packages
 
 setup(
     name='pilab',
-    version='3.0.1',
+    version='3.1.1',
     description='Shared-Libs for the pi-lab microservices',
     url='https://code.fbi.h-da.de/api/v4/projects/27896/packages/pypi/pilab',
     author='Max Reinheimer',