Common - Message Broker - NATS:

- Added wait conditions to ensure Context connects to NATS.

src/common/message_broker/backend/nats/NatsBackendThread.py

@@ -49,13 +49,15 @@ class NatsBackendThread(threading.Thread):
         self._publish_queue.put_nowait(Message(topic_name, message_content))
 
     async def _run_subscriber(
-        self, topic_name : str, timeout : float, out_queue : queue.Queue[Message], unsubscribe : threading.Event
+        self, topic_name : str, timeout : float, out_queue : queue.Queue[Message], unsubscribe : threading.Event,
+        ready_event : threading.Event
     ) -> None:
         LOGGER.info('[_run_subscriber] NATS URI: {:s}'.format(str(self._nats_uri)))
         client = await nats.connect(servers=[self._nats_uri])
         LOGGER.info('[_run_subscriber] Connected!')
         subscription = await client.subscribe(topic_name)
         LOGGER.info('[_run_subscriber] Subscribed!')
+        ready_event.set()
         while not self._terminate.is_set() and not unsubscribe.is_set():
             try:
                 message = await subscription.next_msg(timeout)
@@ -70,8 +72,14 @@ class NatsBackendThread(threading.Thread):
     def subscribe(
         self, topic_name : str, timeout : float, out_queue : queue.Queue[Message], unsubscribe : threading.Event
     ) -> None:
-        task = self._event_loop.create_task(self._run_subscriber(topic_name, timeout, out_queue, unsubscribe))
+        ready_event = threading.Event()
+        task = self._event_loop.create_task(
+            self._run_subscriber(topic_name, timeout, out_queue, unsubscribe, ready_event)
+        )
         self._tasks.append(task)
+        LOGGER.info('[subscribe] Waiting for subscriber to be ready...')
+        is_ready = ready_event.wait(timeout=120)
+        LOGGER.info('[subscribe] Subscriber Ready: {:s}'.format(str(is_ready)))
 
     def run(self) -> None:
         asyncio.set_event_loop(self._event_loop)