CODEWITHSUNDEEP
javascriptnode.jspm2
rass
rass

Reputation: 107

Closing single node server connection closes them all

I barely ask any questions on Stack Overflow, but this one is beyond me. I guess I'm missing something basic as I'm pretty new to Node server.

Our application is pretty basic. The server is supposed to receive a handful of text lines (data), merge and parse them, and once the connection is closed (data sending is over) it sends the data to the api.

var net = require('net');
var fs = require('fs');
const axios = require('axios')

const server = new net.Server();
server.listen(PORT, IP);

server.on("connection", client => {
    client.write("Hello\n");
    console.log('connected');
    
    let received = "";
    client.on("data", data => {
       received += data
       console.log("Partial data is: " + data);
    });

    client.on("close", () => {
        received = received.toString('utf8');
        fs.appendFile('log.txt', received, function (err) {});

        received = received.replace(/(?:\r\n|\r|\n)/g, "||");
        axios.post(APIADDRESS, {data: received});
        console.log('Full data is: '+ {data: received});
    });
});

To send the data I'm simply running a netcat or nc using the netcat ipaddress port, that's not a problem. It's connecting fine, status message is received.

The thing is - once I open two or more connections from two DIFFERENT SSh servers something weird happens. I can send the line after line just fine. The server reports back "partial data" debug without problem, for both of them. However, once I close one of the connections (ctrl+c) they BOTH close. In the end, only the data from the manually closed connection is received. The other one, from a separate nc on a separate ssh server never reaches the client.on("close") part, it seems. It's just terminated for no reason.

Any ideas? I don't even know where to start.

//EDIT Just tested it from my pc and some ssh mobile app using separated SSH servers. As soon as ctrl+c is sent at any device it closes the connection for all clients.

//Forgot to mention I'm running pm2 to keep the server up. Once I turned on the script by hand, ignoring pm2 - it works fine. Weird. It is happening because of PM2.

enter image description here

Upvotes: 0

Views: 180

Answers (2)

rass
rass

Reputation: 107

To anyone coming here in the future.

If you are using pm2 with --watch enabled and the text log file is in the same folder as your main server script... That's the reason why it drops the connection after a single client disconnects. It just detects that the log has changed.

I'm not facepalming, that's not even funny.

Upvotes: 0

jfriend00
jfriend00

Reputation: 707158

I would guess that you have Putty configured to ‘Share SSH connections if possible’. Per some doc, when doing so:

When this mode is in use, the first PuTTY that connected to a given server becomes the ‘upstream’, which means that it is the one managing the real SSH connection. All subsequent PuTTYs which reuse the connection are referred to as ‘downstreams’: they do not connect to the real server at all, but instead connect to the upstream PuTTY via local inter-process communication methods.

So, if you Ctrl+C the PuTTY session that is managing the actual shared connection, they both lose their connection.

You could presumably disable this shared connection feature at either the client or server end of things since both must be enabled for sharing to occur.

Upvotes: 1

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