'close' event triggered soon after the 'connect' event gets triggered

[manju4ever]

Hi All, here is my es6 file, please tell why the close event is trigerred immediately after connect

Node: 6.10.0

Running Docker Instance From : https://hub.docker.com/r/toke/mosquitto/~/dockerfile/

import mqtt from "mqtt";
import jsonfile from "jsonfile";
import path from 'path';

            let  default_options = {
                clientId: `cl_1234`,
                clean: false,
                keepalive: 10 * 1000,
                reconnectPeriod: 90000,
                connectTimeout: 30 * 1000,
                username: "",
                password: "",

            };

             //get broker info from the config file
            let config = jsonfile.readFileSync(path.resolve(process.env.CONFIG));

            //create a singleton, reuse the connection to broker

            const client = mqtt.connect(`mqtt://${config.mqtt.host}`, Object.assign(default_options, config.mqtt.options));

            client.on('connect', () => {
                    console.log(`|| Client - ${deviceId} - Connection to Broker OK !`);
            });

            client.on('reconnect', () => {
                    console.log(`|| Client - ${deviceId} - Connection to Broker Reconnected.`);
            })

            client.on('error', (err) => {
                     console.log(`|| Client - ${deviceId} - Connection to Broker Not Ok - ${err}!`)
            });

            client.on('close', () => {
                    console.log(`|| Client - ${deviceId} - Client Disconnected / Not able to connect to broker :( !`);
            });
export {client};

Is this the right way exporting the client object ?. Please do recommend me some best practices.

[milanito]

I have a similar issue.

It was working about 4 days ago, and now it does not. Here is what happened on our side :

• It goes offline
• It loops on reconnect and close

[mcollina]

Is this a regression between v2.4.0 and v2.5.0?

[milanito]

@mcollina to be fully honest (not that I don't want to blame anyone else but us aha), I'm not 100% sure.

I'm testing on different environment and having the version downgrade to see if it is the case :

• In local, it does break
• On circleci, it did break (yeah I know), it built a few minutes ago

I'll let you know if I can find something more useful than this :/

[mcollina]

@milanito if you understand what's happening, would you mind adding a failing unit test to reproduce and send a PR?

[milanito]

@mcollina If I'm able to, of course

[milanito]

From what I have seen at the moment :

• when I use a RabbitMQ (version 3.6.6) with the MQTT plugin (targeting version 3.1.1) it does work, but there is an error saying :

close Error: premature close
    at Socket.onclose (/Users/....../node_modules/end-of-stream/index.js:44:67)
    at emitOne (events.js:101:20)
    at Socket.emit (events.js:188:7)
    at TCP._handle.close [as _onclose] (net.js:498:12)

• when I use mosca it does not work with the example in the README, but if I do :

const server = new mosca.Server({
    host: 'localhost', // with this line
    port: 1883,
});

it works.

I did try to remove the host part and use either localhost or 127.0.0.1 for my client, it does not work.

I also did try to modify the default host in mosca (defaultsModern in the lib/options.js) which is null, by default. It does work when I remove then the host part.

So I guess, basically on my end, it is more a question of mosca to make my life complete ( :p ), but I can maybe head there to ask why the default host is null.

[mcollina]

I'm a bit lost, as I am missing why the hostname at which the broker listen causes MQTT.js to error.

[milanito]

In my case, if I don't put the host in my options (in mosca) it does not work. I'll try to investigate this weekend what happening under the hood

[0x5e5e]

Having the same issue, it's driving me crazy - the same mqtt code works in one heroku instance I have but doesn't work in another instance that's exactly the same. It connects to the MQTT server just fine, but then throws a 'offline' event, then instantly attempts to reconnect again.

var mqttClient = mqtt.connect('mqtt://SERVER_ENDPOINT');

/** Emitted on successful connection */
mqttClient.on('connect', function() {
  console.log("[MQTT] Connected to MQTT server");
  mqttConnected = true;
  mqttClient.subscribe('reply');
});

/** Emitted on connection error */
mqttClient.on('error', function() {
  console.log("[MQTT] MQTT Error");
  mqttConnected = false;
});

/** Emitted on connection offline status */
mqttClient.on('offline', function() {
  console.log("[MQTT] Connection offline");
  mqttConnected = false;
});

[mcollina]

It seems we can close this now. Feel free to open a new issue if it is still an issue.

[RangerMauve]

I'm getting this exact pattern on iOS when people are on their data plan. I've reverted to 1.4.1 which fixed the looping issue and I'm gonna see which version broke things and hopefully track the details down.

[RangerMauve]

Upgrading from 2.4.0 to 2.8.2 made the issue worse. With 2.4.0 we were only seeing this happen when the app was in the background for a while, but with 2.8.2 it happens after the first time we connect. Sadly we can't debug the problem with breakpoints because connecting the debugger makes the problem go away.

[mcollina]

@RangerMauve can you upload a script/project that reproduces the problem, ideally just using Node.js? Or if you understand why this is happening, can you send a PR?

[RangerMauve]

So far we're only seeing this happening on iOS when users are on a mobile network. I'm not yet sure if it's entirely the client-side that's causing trouble, or if it's related to our broker misbehaving.
My goal is to track down which release caused the problem to manifest and do a PR with a fix. :D

[RangerMauve]

Seems that a change in 2.0.0 effected the issue. Gonna dig around in the code tomorrow.

[marleau]

@RangerMauve Were you able to find a cause for this issue? I'm having a similar problem.

[RangerMauve]

@marleau Sorry for the lack of follow up! Sadly I didn't find the issue and we ended up downgrading our version of mqtt.js for that project. 1.14.1 is what we're using actively right now and it's working fine for all use cases.

[jianfenkezhan]

How to fix it?

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[jaganpaladin]

Hey, could anybody find a solution to this?

[robertsLando]

@jaganpaladin did you tried with latest version?

[jaganpaladin]

Hey @robertsLando , I tried with 5.3.0. what version can should I try with?

[robertsLando]

@jaganpaladin Could you provide a script to repro the issue?

[jaganpaladin]

Hey @robertsLando , thanks for the prompt response. Here's a sample code.

function connectMQTT() {
  return mqtt.connect(connectUrl, {
    clientId,
    clean: true,
    connectTimeout: 4000,
    username: 'xxxxx',
    password: 'xxxxx',
  });
}

let mqttClient = connectMQTT()


mqttClient.on('connect', function () {
  console.log('Connected to MQTT broker');
});

// Handle MQTT errors
mqttClient.on('error', function (error) {
  console.log("Connection error", error)
   if (error && error.code === 2) {
    // Client ID rejection error (code 2)
    console.log('Client ID rejected. Reconnecting with a new client ID.');

    // Generate a new unique client ID
    const newClientId = generateUniqueClientId(); //  logic to generate a unique client ID (sample: emqx_cloud_1756)
    mqttClient = connectMQTT(newClientId); // Updating the mqttClient variable with the new client and the new client ID
  } else {
    // Other errors
    handleDisconnect();
  }
});

// Handle MQTT close
mqttClient.on('close', function () {
  console.log('MQTT Connection Closed');
  handleDisconnect();
  mqttClient = connectMQTT();
});

So, i'm trying to run this as a google cloud function so that i can return the mqtt response to my front end over a http based APIs.

Here's how it goes:

exports.helloWorld = functions.https.onRequest(async (req, res) => {
mqttClient.publish(topic, message)
mqttClient.subscribe(topic, callback function(){
})

}

Hope this helps.

[robertsLando]

@jaganpaladin That piece of code is a standard mqtt client connection, I'm using mqttjs in lot of project both on frontend and backend side and I never faced such problem. I have a feel this is something related to broker side. I suggest you to try reproduce the issue using paho-mqtt or other mqtt clients to see if they have the same behaviour

[jaganpaladin]

Hi @robertsLando , thank you. I'll try that and let you know.