Trace Retrieval: message handling while running flask

Working message sending and receiving while running the flask service

.gitignore

 **/__pycache__
+*.log
\ No newline at end of file

message-broker/rabbit-mq-test/consumer.py

 import pika
 
-EXCHANGE_NAME = 'beacon'
+EXCHANGE_NAME = 'rest-gateway'
+EXCHANGE_TYPE = 'direct'
 
 connection = pika.BlockingConnection(pika.ConnectionParameters('143.205.173.36', 30302, heartbeat=600, blocked_connection_timeout=300))
 channel = connection.channel()
 
-channel.exchange_declare(exchange=EXCHANGE_NAME, exchange_type='fanout')
-result = channel.queue_declare(queue='', exclusive=True)
+channel.exchange_declare(exchange=EXCHANGE_NAME, exchange_type=EXCHANGE_TYPE)
+result = channel.queue_declare(queue='rest-gateway', exclusive=True, auto_delete=True)
 queue_name = result.method.queue
-channel.queue_bind(exchange=EXCHANGE_NAME, queue=queue_name, routing_key='')
+channel.queue_bind(exchange=EXCHANGE_NAME, queue=queue_name, routing_key='rest-gateway')
 
 def callback(ch, method, properties, body):
     print(f"### Received: {body}")

transaction-hub-in/trace-retrieval-microservice/app/messages/MessageHandler.py → modules/messaging/MessageReceiver.py

 import pika
 import functools
 from threading import Thread
-import logging
 
-LOG_FORMAT = ('%(levelname) -10s %(asctime)s %(name) -30s %(funcName) '
-              '-35s %(lineno) -5d: %(message)s')
-logging.basicConfig(level=logging.INFO, format=LOG_FORMAT)
+import logging
 LOGGER = logging.getLogger(__name__)
 
-class MessageHandler:
-    _exchange_name = 'beacon'
-    _rabbit_mq_ip = '143.205.173.36'
-    _rabbit_mq_port = 30302
+class MessageReceiver:
+
+    _exchange_name = None
+    _exchange_type = None
+    _rabbit_mq_ip = None
+    _rabbit_mq_port = None
+    _auto_ack = None
+    _queue_name = None
 
-    def __init__(self, exchange_name=None, rabbit_mq_ip=None, rabbit_mq_port=None):
-        if exchange_name != None:
+    _connection: pika.SelectConnection = None
+    _message_received_callback = None
+
+    def __init__(self, exchange_name='beacon', exchange_type='fanout', rabbit_mq_ip='143.205.173.36', rabbit_mq_port=30302, queue_name='', auto_ack=True):
         self._exchange_name = exchange_name
-        if rabbit_mq_ip != None:
+        self._exchange_type = exchange_type
         self._rabbit_mq_ip = rabbit_mq_ip
-        if rabbit_mq_port != None:
         self._rabbit_mq_port = rabbit_mq_port
+        self._auto_ack = auto_ack
+        self._queue_name = queue_name
+
+    #region Connection establishment
 
-    def _pika_connect(self):
+    def _connect(self) -> pika.SelectConnection:
         connection = pika.SelectConnection(parameters=pika.ConnectionParameters(self._rabbit_mq_ip, self._rabbit_mq_port), 
             on_open_callback=self._connection_opened_callback, on_open_error_callback=self._connection_opened_error)
         return connection
@@ -31,40 +37,41 @@ class MessageHandler:
         connection.channel(on_open_callback=self._channel_created_callback)
 
     def _connection_opened_error(self, connection, err):
-        print('## Error: ' + str(err))
+        LOGGER.error(f"RabbitMQ connection could not be established: {str(err)}")
 
     def _channel_created_callback(self, channel: pika.channel.Channel):
         # Create exchange
         cb = functools.partial(self._exchange_created_callback, userdata=channel)
-        channel.exchange_declare(exchange=self._exchange_name, exchange_type='fanout', callback=cb)
+        channel.exchange_declare(exchange=self._exchange_name, exchange_type=self._exchange_type, callback=cb)
 
     def _exchange_created_callback(self, answer_message, userdata):
         # Create queue
         channel = userdata
         cb = functools.partial(self._queue_created_callback, userdata=channel)
-        channel.queue_declare(queue='', exclusive=True, callback=cb)
+        channel.queue_declare(queue=self._queue_name, exclusive=False, callback=cb)
 
     def _queue_created_callback(self, answer_message: pika.frame.Method, userdata):
         queue_name = answer_message.method.queue
         channel = userdata
         
         # Bind queue to exchange
-        channel.queue_bind(exchange=self._exchange_name, queue=queue_name, routing_key='')
-        LOGGER.info(f"Rabbit MQ connection to exchange '{self._exchange_name}' established")
+        channel.queue_bind(exchange=self._exchange_name, queue=queue_name)
+        LOGGER.info(f"RabbitMQ connection to exchange '{self._exchange_name}' established")
 
         # Consume messages
-        channel.basic_consume(queue=queue_name, auto_ack=False, on_message_callback=_message_received_callback)
+        channel.basic_consume(queue=queue_name, auto_ack=self._auto_ack, on_message_callback=self._message_received_callback)
+
+    #endregion Connection establishment
 
     def start(self, message_received_callback):
-        '''Starts the message handling'''
-        global _message_received_callback
-        _message_received_callback = message_received_callback
+        '''Connects to RabbitMQ and starts listening for messages'''
+        self._message_received_callback = message_received_callback
 
-        global _connection 
-        _connection = self._pika_connect()
-        Thread(target=_connection.ioloop.start).start()
+        self._connection = self._connect()
+        Thread(target=self._connection.ioloop.start).start()
 
     def stop(self):
-        _connection.ioloop.stop()
-        _connection.close()
-        LOGGER.info(f"Rabbit MQ connection closed")
\ No newline at end of file
+        '''Stops listening for messages and closes the connection'''
+        self._connection.ioloop.stop()
+        self._connection.close()
+        LOGGER.info(f"RabbitMQ connection closed")
\ No newline at end of file

modules/messaging/MessageSender.py

+import pika
+import functools
+from threading import Thread
+
+import logging
+LOGGER = logging.getLogger(__name__)
+
+class MessageSender:
+    
+    _rabbit_mq_ip = None
+    _rabbit_mq_port = None
+
+    _connection: pika.BlockingConnection = None
+    _channel: pika.channel.Channel = None
+
+    def __init__(self, rabbit_mq_ip='143.205.173.36', rabbit_mq_port=30302):
+        self._rabbit_mq_ip = rabbit_mq_ip
+        self._rabbit_mq_port = rabbit_mq_port
+
+    def connect(self):
+        '''Connects to RabbitMQ'''
+        self._connection = pika.BlockingConnection(parameters=pika.ConnectionParameters(self._rabbit_mq_ip, self._rabbit_mq_port))
+        self._channel = self._connection.channel()
+        LOGGER.info(f"RabbitMQ connection established")
+
+    def create_exchange(self, exchange_name, exchange_type):
+        '''Creates the exchange if not existent'''
+        self._channel.exchange_declare(exchange=exchange_name, exchange_type=exchange_type)
+
+    def send(self, exchange_name, message, routing_key=''):
+        '''Sends a message to the exchange'''
+        if self._channel == None:
+            LOGGER.error("Tried to send before connection to RabbitMQ was established")
+            raise RuntimeError("Connection to RabbitMQ not established, call MessageSender.connect() first")
+            
+        self._channel.basic_publish(exchange=exchange_name, routing_key=routing_key, body=message)
+
+    def disconnect(self):
+        '''Disconnects from RabbitMQ'''
+        if self._connection == None:
+            LOGGER.error("Tried to close connection before connection to RabbitMQ was established")
+            raise RuntimeError("Connection to RabbitMQ not established")
+
+        self._connection.close()
+        LOGGER.info(f"RabbitMQ connection closed")
\ No newline at end of file

transaction-hub-in/trace-retrieval-microservice/app/main.py

+import sys
+sys.path.insert(1, '../../../modules/')
+
+import logging
+LOG_FORMAT = ('%(levelname) -5s %(asctime)s %(name)s:%(funcName) -35s %(lineno) -5d:  %(message)s')
+logging.basicConfig(filename='trace-retrieval.log', level=logging.WARNING, format=LOG_FORMAT)
+LOGGER = logging.getLogger(__name__)
+
 import connexion
-from messages.MessageHandler import MessageHandler
+from messaging.MessageReceiver import MessageReceiver
+from messaging.MessageSender import MessageSender
+
+message_sender = None
 
 # init message handler
 def message_received_callback(channel, method, properties, body):
-    print(f"### NICE: {body}")
-    channel.basic_ack(delivery_tag=method.delivery_tag)
+    print(f"### Received: {body}")
+    # channel.basic_ack(delivery_tag=method.delivery_tag)
+    message_sender.send('rest-gateway', str(body) + ' (sent from trace-retrieval-microservice)', 'rest-gateway')
 
 # load swagger config 
 app = connexion.App(__name__, specification_dir='configs/')
@@ -16,7 +28,11 @@ def api_root():
 
 # start app
 if __name__ == '__main__':
-    message_handler = MessageHandler()
-    message_handler.start(message_received_callback)
+    message_rec = MessageReceiver(exchange_name='inhub', exchange_type='direct', queue_name='trace-retrieval', auto_ack=True)
+    message_rec.start(message_received_callback)
+
+    message_sender = MessageSender()
+    message_sender.connect()
+    message_sender.create_exchange('rest-gateway', 'direct')
 
     app.run(host='0.0.0.0', port=5000, debug=True, use_reloader=False) # disable reloader so only subscribed once to rabbitmq