[SOLVED] Publish message to IoTHub via Micronaut MQTT and cert-authentification

Publish message to IoTHub via Micronaut MQTT and cert-authentification

I'm trying to connect to IoTHub using Micronaut MQTT. I've a valid client key and certificate as well as the IoTHub-ca-cert.

In my application.yml, I've the following config:

mqtt:
  client:
    server-uri: ssl://<iothub-name>.azure-devices.net:8883
    client-id: <device-id>
    user-name: <iothub-name>.azure-devices.net/<device-id>/?api-version=2021-04-12
    ssl:
      certificate:
        classpath:curl_est_crt.pem
      private-key:
        classpath:curl_est_key.pem
      certificate-authority:
        classpath:iothub.pem

But if I try to send a message to the IoT-Hub, it fails with the following exception

io.micronaut.http.server.RouteExecutor - Unexpected error occurred: Error instantiating bean of type  [io.micronaut.mqtt.v5.intercept.MqttIntroductionAdvice]
Message: Implementation specific error.

Caused by: org.eclipse.paho.mqttv5.common.MqttException: Implementation specific error.
    at org.eclipse.paho.mqttv5.client.internal.ExceptionHelper.createMqttException(ExceptionHelper.java:32)
    at org.eclipse.paho.mqttv5.client.internal.ClientState.notifyReceivedAck(ClientState.java:1074)
    at org.eclipse.paho.mqttv5.client.internal.CommsReceiver.run(CommsReceiver.java:153)
    at io.micronaut.core.propagation.PropagatedContext.lambda$wrap$3(PropagatedContext.java:211)
    at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:572)
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:317)
    at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)

I've read that IoTHub requires TLSv1.2. Is this standard for micronaut or do I have to set this somewhere? (Or am I completely wrong and something else is causing this error? (I can't debug it because then I get a timeout...))

I know that somehow I could use the device-sdk but I need to authenticate via x509 certificates and I couldn't figure out how to set this up.

Solution

It looks like you are using MQTT v5. (org.eclipse.paho.mqttv5.common.MqttException) An Azure IoT hub only supports MQTT v3.1. An "implementation error" would sound like a likely error message in that scenario. It also appears likely that the X.509 authentication was successful.