_http_server / TLSSocket : MaxListenersExceededWarning

[radixxko]

Hello after using simple https server forked into 2 child processes via node native cluster module we are getting MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 error listeners added. warning

Minimal code where the issue is present:

const https = require('https'), fs = require('fs'), cluster = require('cluster');

if( cluster.isMaster )
{
    cluster.fork();
    cluster.fork();
}
else
{
    let server = https.createServer(
    {
        ca : fs.readFileSync('chain.pem'),
        cert : fs.readFileSync('server.crt'),
        key : fs.readFileSync('private.key'),
        passphrase  : 'PASS'
    },
    function( req, res ){ res.end('Hello') });

    server.listen( 7443 );
}

The issue is present in v10.0.0 node version as well it is replicable in 9.x version.

Funny thing is that we are getting MaxListenersExceededWarning every few seconds even if there are no clients connecting to server.

Any hints?

[bnoordhuis]

Can you start node with --trace-warnings and post the trace?

[radixxko]

Sure thing

MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 error listeners added. Use emitter.setMaxListeners() to increase limit
    at _addListener (events.js:244:19)
    at TLSSocket.addListener (events.js:261:10)
    at TLSSocket.Readable.on (_stream_readable.js:805:35)
    at TLSSocket.socketOnWrap [as on] (_http_server.js:700:37)
    at TLSSocket.socketOnError (_http_server.js:490:8)
    at onParserExecuteCommon (_http_server.js:507:19)
    at onParserExecute (_http_server.js:481:3)

[lpinca]

@radixxko not sure if it's a problem but the screenshot above seems to expose a password.

[radixxko]

Thanks for the warning @lpinca, credentials are used just for the testing purposes so no issue there

[lpinca]

I can't reproduce, this is my test case with a self signed certificate.

const cluster = require('cluster');
const fs = require('fs');
const https = require('https');

if (cluster.isMaster) {
  cluster.fork();
  cluster.fork();
} else {
  const server = https.createServer({
    cert: fs.readFileSync('certificate.pem'),
    key: fs.readFileSync('key.pem')
  });

  server.on('request', function (req, res) {
    res.end('Hello');
  });

  server.listen(8080);
}

[bnoordhuis]

Seeing there's been no reproduction, I'm going to close this out. Thanks anyway for the report.