(Paho) MQTT callback does not get closed

Question

I am using the MQTT API in my project to read data. (org.eclipse.paho org.eclipse.paho.client.mqttv3)

When I am closing the client, the mqttcallback is still active. I close mqtt by calling unsubscribe(...), disconnect() and close() on the object.

I tried setting the callback to null as well. Nothing helps.

After the mqtt client has closed. This is the trace which still keeps appearing in the logs.

> com.xxx.binge.sources.mqtt.BingeMQTTReader$BingeMQTTCallback.connectionLost(BingeMQTTReader.java:479)
>             at org.eclipse.paho.client.mqttv3.internal.CommsCallback.connectionLost(CommsCallback.java:247)
>             at org.eclipse.paho.client.mqttv3.internal.ClientComms.shutdownConnection(ClientComms.java:356)
>             at org.eclipse.paho.client.mqttv3.internal.CommsReceiver.run(CommsReceiver.java:146)
>             at java.lang.Thread.run(Thread.java:745)
>     Caused by: com.xxx.vds.api.VDSException: MQTT Connection exception
>             at com.xxx.binge.sources.mqtt.BingeMQTTReader.reconnectWithRetry(BingeMQTTReader.java:334)
>             at com.xxx.binge.sources.mqtt.BingeMQTTReader.access$200(BingeMQTTReader.java:46)
>             at com.xxx.binge.sources.mqtt.BingeMQTTReader$BingeMQTTCallback.connectionLost(BingeMQTTReader.java:473)
>             ... 4 more
>     Caused by: Unable to connect to server (32103) - java.net.ConnectException: Connection refused
>             at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:79)
>             at org.eclipse.paho.client.mqttv3.internal.ClientComms$ConnectBG.run(ClientComms.java:590)
>             ... 1 more
>     Caused by: java.net.ConnectException: Connection refused
>             at java.net.PlainSocketImpl.socketConnect(Native Method)
>             at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)
>             at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)
>             at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)
>             at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
>             at java.net.Socket.connect(Socket.java:579)
>             at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:70)
>             ... 2 more

Abdul Manaf · Answer 1 · 2015-10-28T09:34:05.193

1

try this code

// Construct the MqttClient instance
       MqttClient   client = new MqttClient(brokerUrl, clientId);
// Set this wrapper as the callback handler
       client.setCallback(this);
// Connect to the server
       client.connect();
// Disconnect the client
       client.disconnect();

edited Oct 28 '15 at 09:34

answered Oct 28 '15 at 05:00

Abdul Manaf

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my MqttClient stops properly for me. The problem is with the MqttCallback not closing. This thread keeps running. this is how I set the callback ` BingeMQTTCallback implements MqttCallback {...} callback = new BingeMQTTCallback(); client.setCallback(callback); ` The logs posted in the question are after the client.disconnect() has been called. – nandini Oct 28 '15 at 09:09
Set the current wrapper as the callback handler – Abdul Manaf Oct 28 '15 at 09:34
Ok, will give this a try and update you. Currently I have it as a inner class in my application. – nandini Oct 28 '15 at 10:04

score 1 · Answer 2 · answered Oct 28 '15 at 10:19

mqtt publish sample java code

import java.text.SimpleDateFormat;
import java.util.Date;
import org.apache.log4j.Logger;
import com.ibm.micro.client.mqttv3.MqttCallback;
import com.ibm.micro.client.mqttv3.MqttClient;
import com.ibm.micro.client.mqttv3.MqttDeliveryToken;
import com.ibm.micro.client.mqttv3.MqttException;
import com.ibm.micro.client.mqttv3.MqttMessage;
import com.ibm.micro.client.mqttv3.MqttTopic;

public class testMqtt implements MqttCallback {

final static Logger logger = Logger.getLogger(Publish.class);
public SimpleDateFormat loggerdateFormat = new SimpleDateFormat(
        "yyyy MMM dd HH:mm:ss");

public String send(String topicName, String msg) {
    logger.info(loggerdateFormat.format(new Date())
            + " Control on method : send ");
    String topic = topicName;
    String message = msg;
    logger.info(loggerdateFormat.format(new Date()) + " Message " + message);
    if (message.trim().equals("-1")) {
        logger.error(loggerdateFormat.format(new Date())
                + " : message wrong");
        return "fail";
    }
    int qos = 2;
    String url = "tcp://" + Config.Mqtt.BROCKER + ":" + Config.Mqtt.PORT;
    String clientId = "Client-1";

    try {

        Publish sampleClient = new Publish(url, clientId);
        sampleClient.publish(topic, qos, message.getBytes());
    } catch (Exception me) {
        me.printStackTrace();
    }

    return "ok";
}

// Private instance variables
private MqttClient client;
private String brokerUrl;

public testMqtt(String brokerUrl, String clientId) throws MqttException {
    this.brokerUrl = brokerUrl;
    try {
        // Construct the MqttClient instance
        client = new MqttClient(this.brokerUrl, clientId);
        // Set this wrapper as the callback handler
        client.setCallback(this);
    } catch (Exception e) {
        e.printStackTrace();
        log("Unable to set up client: " + e.toString());
        System.exit(1);
    }
}

public testMqtt() {
    // TODO Auto-generated constructor stub
}

public void publish(String topicName, int qos, byte[] payload)
        throws MqttException {

    // Connect to the server
    log("Connecting to " + brokerUrl);
    try {
        // Connect to the server
        client.connect();
    } catch (Exception e) {

        log("Unable to connect: " + e.toString());
        return;
    }
    log("Connected !!!");

    // Get an instance of the topic
    MqttTopic topic = client.getTopic(topicName);

    // Construct the message to publish
    MqttMessage message = new MqttMessage(payload);
    message.setQos(qos);

    // Publish the message
    log("Publishing to topic \"" + topicName + "\" qos " + qos);
    MqttDeliveryToken token = topic.publish(message);

    // Wait until the message has been delivered to the server
    token.waitForCompletion();

    // Disconnect the client
    client.disconnect();
    log("Disconnected");
}

private void log(String message) {
    logger.info(loggerdateFormat.format(new Date()) + ": log - " + message);
}

// Called when the connection to the server has been lost.
public void connectionLost(Throwable cause) {
    log("Connection to " + brokerUrl + " lost!");
    System.exit(1);
}

public void deliveryComplete(MqttDeliveryToken token) {
    log("Message Delivered Successfully!!!");
}

// Called when a message arrives from the server.
public void messageArrived(MqttTopic topic, MqttMessage message)
        throws MqttException {
    logger.info(loggerdateFormat.format(new Date()) + " : Topic:\t\t"
            + topic.getName());
    logger.info(loggerdateFormat.format(new Date()) + " : Message:\t"
            + new String(message.getPayload()));
    logger.info(loggerdateFormat.format(new Date()) + " : QoS:\t\t"
            + message.getQos());
}

}

paho mqtt not ibm.. group id org.eclipse.paho/ artifact id : org.eclipse.paho org.eclipse.paho.client.mqttv3 I tried setting callback to this. Same still :(. — nandini, Oct 30 '15 at 13:06

(Paho) MQTT callback does not get closed

2 Answers2