Connect to unix socket

[ralight]

Would you consider support for connecting to unix sockets? The use case is a local application wanting to connect to a local MQTT broker without having to create a network.

It looks like lib/connect/unix.js would be very similar to tcp.js, but with this sort of construct instead:

    unixpath = '/var/run/mqtt.socket'

    return net.createConnection(unixpath)

[mcollina]

Definitely! I have no bandwidth to work on this, but I’ll be happy to review a PR Il 6 feb 2020, 13:03 +0100, Roger Light <notifications@github.com>, ha scritto:

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Would you consider support for connecting to unix sockets? The use case is a local application wanting to connect to a local MQTT broker without having to create a network. It looks like lib/connect/unix.js would be very similar to tcp.js, but with this sort of construct instead: unixpath = '/var/run/mqtt.socket' return net.createConnection(unixpath) — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or unsubscribe.

[ralight]

Thanks, I'll take a look.

[natcl]

Any updates on this ? Would be interested in this feature too !

[ralight]

I hadn't done any more because of this: #1094 , but that has been closed now for some reason. It wasn't clear what to use as the URL prefix, otherwise I suspect it may have got further.

I've been using my own modified version just fine, I'd be happy for anyone to take this over.

[RuStrannik]

I suggest using unix:// prefix, which also used in nginx configs (those are really widespread and well known). Native mosquitto clients also use option --unix to specify path to unix socket.

I am really confused why it has not been accepted yet. This feature is clearly useful for security, doesn't break anything, and there is not that much to review! Literally 1 line of code and 1 file with 6 lines of really simple and straight-forward code added. Is project dead / in hibernation or what?

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[natcl]

We're still interested in this!

[nik-sie]

It's actually possible to connect to a unix socket right now.
Check this out:

'use strict';
const mqtt = require('mqtt');
const cfg = { path: "/run/mosquitto/mosquitto.sock", username: "user", password: "pass" };
const client = mqtt.connect(cfg);
client.on('error', (err) => { if (err) { console.error(err); }; });
client.on('connect', (conn_evt) => {
    console.log("mqtt: connected. Subscribing...");
    client.subscribe(['#'], { nl: true }, (err, granted) => { console.log("granted:", granted); });
});
client.on('message', (path, data, packet) => { console.log("mqtt_msg_in: ['%s']:(%d) '%s'", path, data.length, data.toString()); });

[robertsLando]

I dunno how that code could work @nik-sie, the PR adding unix socket support has never been merged. Maybe the default tcp handler could work as it support sockets too

[nik-sie]

@robertsLando, If you really want to use unix sockets, just try it, it works, I've been using it for a long time.
It works, since MqttClient uses node's native net.createConnection() call under the hood, which accepts path option (if given) to create connection to an IPC.
The PR would only add convenience of using URLs, that's it.

[rockey2020]

no working at 5.5.3

 const mqttOptions: IClientOptions = {
    path: createMQTTClientProps.remoteConnection.address,
  };

  console.log(mqttOptions);

  const mqttClient: MqttClient = await mqtt.connectAsync(
    createMQTTClientProps.remoteConnection.address,
  );

when i replace unix string ,stil no working

[nik-sie]

@rockey2020, there should NOT be any prefixes to the path, remove the unix:// part.
Also, make sure your mqtt client actually has read+write access to the socket file.

[nik-sie]

I did a quick test and, apparently, compiled ts -> js output indeed changed drastically, so old simple method doesn't work anymore.
Here is how it works now:

'use strict';

const net = require('node:net');
const mqtt = require('mqtt');

function streamBuilder() { return net.createConnection({ path: "/run/mosquitto/mosquitto.sock" }); };
function msgRecv(path, data, packet) { console.log("mqtt_msg_in: ['%s']:(%d) '%s'", path, data.length, data.toString()); };

const client = new mqtt.Client(streamBuilder, { username: "user", password: "pass" });
client.on('error', (err) => { if (!err) { return; }; console.error(err); client.end(); });
client.on('connect', (conn_evt) => {
    console.log("mqtt: connected. Subscribing...");
    client.subscribe(['#'], { nl: true }, (err, granted) => { console.log("granted:", granted); });
});
client.on('message', msgRecv);

[robertsLando]

I think the problem is the path argument is not passed down correctly to the createConnection, does someone wants to submit a PR for that?

[drdaeman]

May I suggest reopening this (or should I create a new issue?) for URI-based support, e.g. mqtt:///run/mosquitto/mosquitto.socket, mqtt+unix:///run/mosquitto/mosquitto.socket, or something similar?

The idea is that it would allow various projects (I'm thinking about Zigbee2MQTT, which currently doesn't seem to have a way to specify path in their configuration file) that use this library to automagically start supporting connecting to UNIX sockets without any code changes besides, of course, bumping their mqtt.js dependency version.

Thanks!

[robertsLando]

@drdaeman want to submit a PR?