Connecting to Named Unix Domain Socket Node

Question

I am trying to connect to a named Unix Domain Socket via nodejs. I have seen that the docs seem to support connecting to Unix Sockets, however I haven't seen any examples of connecting to a socket by name, and not by accessing a socket file at a well known location.

I can clearly see that the socket I need to connect to is being created by using lsof (and some grepping):

COMMAND    PID  USER   FD   TYPE             DEVICE SIZE/OFF  NODE NAME
run       5632 user    3u  unix 0xffff8803dd4b6000      0t0 29647 @#user#5632#1 type=SEQPACKET

The name of the socket is being passed to the script that actually runs my node script. I have tried the following:

import net = require('net');
var socket;
var element = "#user#5632#1"; //Parsed from args
try {
    socket = net.createConnection("@"+element,(error)=>{
        if(error){
            console.log(error)
        }else{
            console.log("Connection Established "+element);}
        });
        socket.on('error', function(err) {
            console.log("Error: " + err);
        });
    } catch (error) {
        console.error(error);
    }

Clearly, I have this wrapped up to catch errors in a few places(at different points in execution), but the point is that createConnection is throwing:

Error: Error: connect ENOENT @#user#5882#1

Using net.connectcauses the exact same error.

I tested creating a socket (file) in a well known location, and connecting to is, and that worked just fine, but as far as I have determined, node, or at least the net module does not seem to support connecting to ephemeral sockets.

Anybody know if there is a way to do this, or if I need to format my socket name differently in order to connect or any help really?

I'm not exactly sure but I thought you need to add a \0 before the name if you want to connect or create to an abstract namespace unix domain socket. man UNIX(7):(abstract: an abstract socket address is distinguished (from a pathname socket) by the fact that sun_path[0] is a null byte ('\0')) So it might work if you use either \0#user#5632#1 or \0@#user#5632#1. But I never tried that myself. — t.niese
@t.niese That did at least change the error from not finding the socket to not being able to connect to the socket, but nevertheless, it seems that Node does not support this socket type. Thanks anyway! — Devon Herlitz

mscdex mscdex · Accepted Answer · 2016-09-28T20:05:38

Node does not support SEQPACKET sockets. You may submit a PR to the node issue tracker as a feature request to add support and/or you may need to write a node addon that lets you connect to SEQPACKET sockets.

Connecting to Named Unix Domain Socket Node

1 Answers