CODEWITHSUNDEEP
pythondocker
Eugene
Eugene

Reputation: 1125

Python mqtt client in a test docker container connecting to mqtt broker docker container

i have a test container containing a python script unit test to test the connection to a mqtt broker. The mqtt broker is another docker container using eclipse-mosquitto:latest.

I have also created a docker network.

Below are the docker statements:

docker network create test_network
docker run -d -p 21883:1883 --name=gatewaymqtt --network=test_network -v "$PWD/work/mosquitto/config/mosquitto.conf:/mosquitto/config/mosquitto.conf" -v "$PWD/work/mosquitto/data:/mosquitto/data" -v "$PWD/work/mosquitto/log:/mosquitto/log" eclipse-mosquitto:latest

docker build -t test -f ./Dockerfile-test .
docker run --network=test_network test

Inside the test container it is running this python unit test:

class TestClient(unittest.TestCase):

def test_mqtt_connect(self):
    log = logging.getLogger("test_mqtt_connect")
    # The callback for when the client receives a CONNACK response from the server.
    def on_connect(client, userdata, flags, rc):
        log.debug("Connected with result code "+str(rc))

        # Subscribing in on_connect() means that if we lose the connection and
        # reconnect then subscriptions will be renewed.
        #client.subscribe("$SYS/#")

    # The callback for when a PUBLISH message is received from the server.
    def on_message(client, userdata, msg):
        log.debug(msg.topic+" "+str(msg.payload))

    client = mqtt.Client()
    client.on_connect = on_connect
    client.on_message = on_message

    client.connect("gatewaymqtt ", 21883, 60)
    sleep(5)
    client.disconnect()

if __name__ == '__main__':
    unittest.main()

However, I do not see any incoming connection from the test container?

This is the log of the test container:

======================================================================
ERROR: test_mqtt_connect (__main__.TestClient)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "test_socketio.py", line 69, in test_mqtt_connect
    client.connect("gatewaymqtt ", 21883, 60)
  File "/usr/local/lib/python3.7/site-packages/paho/mqtt/client.py", line 937, in connect
    return self.reconnect()
  File "/usr/local/lib/python3.7/site-packages/paho/mqtt/client.py", line 1071, in reconnect
    sock = self._create_socket_connection()
  File "/usr/local/lib/python3.7/site-packages/paho/mqtt/client.py", line 3522, in _create_socket_connection
    return socket.create_connection(addr, source_address=source, timeout=self._keepalive)
  File "/usr/local/lib/python3.7/socket.py", line 728, in create_connection
    raise err
  File "/usr/local/lib/python3.7/socket.py", line 716, in create_connection
    sock.connect(sa)
ConnectionRefusedError: [Errno 111] Connection refused

----------------------------------------------------------------------

Upvotes: 2

Views: 4315

Answers (1)

makozaki
makozaki

Reputation: 4366

When you connect inside docker network use actual port, not exposed one. You should use 21883 when you connect to docker host and 1883 inside docker network.

...
client.connect("gatewaymqtt ", 1883, 60)
...

Upvotes: 1

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