Resubscribe in onConnectionResumed()

[cjacky475]

Hello, how to correctly resubscribe to my sensors/5 topic again in onConnectionResumed() method? Sometimes my connection gets dropped with the error Connection interrupted: 5134: The connection was closed unexpectedly. and after that I am not receiving any messages from that topic, I have to restart the Spring Boot app. How to correctly solves this issue? Thank you.

private final MqttClientConnectionEvents callbacks = new MqttClientConnectionEvents() {
        @Override
        public void onConnectionInterrupted(int errorCode) {
            logger.error("Connection interrupted: " + errorCode + ": " + CRT.awsErrorString(errorCode));
        }

        @Override
        public void onConnectionResumed(boolean sessionPresent) {
            logger.info("Connection resumed: " + (sessionPresent ? "existing session" : "clean session"));
        }
    };

public void connect(String clientID) {
        AwsIotMqttConnectionBuilder builder = AwsIotMqttConnectionBuilder
                .newMtlsBuilderFromPath("src/main/resources/certificate.pem.crt", "src/main/resources/private_key.pem.key");

        ClientBootstrap clientBootstrap = new ClientBootstrap(null, null);

        MqttClientConnection clientConnection = builder
                .withConnectionEventCallbacks(callbacks)
                .withCleanSession(false)
                .withBootstrap(clientBootstrap)
                .withClientId(clientID)
                .withCertificateAuthorityFromPath(null, "src/main/resources/AmazonRootCA1.pem")
                .withEndpoint("aaaaaaaaaaaa-ats.iot.us-east-2.amazonaws.com")
                .withProtocolOperationTimeoutMs(80000)
                .build();

        try {
            clientConnection.connect().get(TIMEOUT_SECONDS, TimeUnit.SECONDS);

            clientConnection.subscribe("sensors/5", QualityOfService.AT_LEAST_ONCE, mqttMessage -> {
                System.out.println("MESSAGE: " + Arrays.toString(mqttMessage.getPayload()));
            });
        } catch (InterruptedException | ExecutionException | TimeoutException e) {
            e.printStackTrace();
        }
    }

[jmklix]

You shouldn't need to resubscribe since you are using .withCleanSession(false). How long are you disconnected for? Can you attach logs from this happening?

[jmklix]

Marking as answer. Please open new discussion if you are still having problems with receiving messages after reconnecting

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