feat/#63 - add iterator instead of RabbitMQ callback

amqp/service/amq_service.py

@@ -4,7 +4,7 @@ import logging.config
 import os
 from asyncio import Future
 from threading import Thread
-from typing import Optional
+from typing import AsyncIterator, Optional
 
 from aio_pika.abc import AbstractRobustExchange
 
@@ -12,7 +12,7 @@ from amqp.adapter.amq_route_factory import AMQRouteFactory
 from amqp.adapter.backpressure_handler import BackpressureHandler
 from amqp.adapter.consul_global_id_generator import get_unique_instance_id
 from amqp.adapter.data_message_factory import DataMessageFactory
-from amqp.adapter.logging_utils import logging_info, logging_warning
+from amqp.adapter.logging_utils import logging_error, logging_info, logging_warning
 from amqp.adapter.service_message_factory import ServiceMessageFactory
 from amqp.config.amq_configuration import AMQConfiguration
 from amqp.model.model import AMQRoute, DataMessage
@@ -65,6 +65,7 @@ class AMQService:
         self.backpressure_thread: Optional[Thread] = None
         self.backpressure_handler: Optional[BackpressureHandler] = None
         self.maximum_availability = -1
+        self.future: Future = asyncio.Future()
 
     # =======================================================================
     # =======================================================================
@@ -82,6 +83,7 @@ class AMQService:
         logging.info("***********************************************")
         logging.info("******  AMQ   Service  Init  Complete *********")
         logging.info("***********************************************")
+        self.future.set_result(True)
         self.loop.run_forever()
 
     def backpressure(self, current_availability: int, maximum: int = -1):
@@ -163,6 +165,48 @@ class AMQService:
             return True
         return False
 
+    async def data_message_generator(self, route: AMQRoute) -> AsyncIterator[DataMessage]:
+        """
+        An async iterator that blocks until messages arrive, processes them,
+        and continues in a loop.
+
+        :param queue_name: The name of the queue to consume messages from
+        :yield: The processed DataResponse for each message
+        """
+        # Get a channel from the connection
+        channel = self.rabbit_mq_client.channel
+        queue_args = (
+            self.rabbit_mq_client.DLQ_ARGS if self.amq_configuration.dispatch.use_dlq else None
+        )
+        queue = await channel.declare_queue(
+            route.queue,
+            durable=True,
+            exclusive=False,
+            auto_delete=False,
+            arguments=queue_args,
+        )
+        await queue.bind(route.exchange, route.key)
+        # Start consuming without a callback
+        async with queue.iterator() as queue_iter:
+            async for message in queue_iter:
+                try:
+                    # Process the message using the same logic as in inbound_data_message_callback_no_thread
+                    data_message: DataMessage = (
+                        await self.amq_data_message_handler.reconstitute_data_message(message)
+                    )
+
+                    success = yield data_message
+                    if not success:
+                        logging_warning(f"Message processing failed for {data_message.id()}.")
+                        # Nack the message without requeuing in case of failure
+                        await message.nack(requeue=False)
+                    else:
+                        await message.ack()
+                except Exception as e:
+                    logging_error(f"Error processing message: {e}")
+                    # Nack the message without requeuing in case of error
+                    await message.nack(requeue=False)
+
     def get_unique_instance_id(self) -> int:
         """
         Provides cluster-wide unique instance ID for this AMQ service instance.