Release #43 throws an error after a couple of refreshes

[klaasman]

Waiting for file changes...

events.js:183
      throw er; // Unhandled 'error' event
      ^

Error: read ECONNRESET
    at _errnoException (util.js:1024:11)
    at TCP.onread (net.js:615:25)
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

Trace with longjohn:

Waiting for file changes...

Error: read ECONNRESET
    at _errnoException (util.js:1024:11)
    at TCP.onread (net.js:615:25)
---------------------------------------------
    at Socket.Readable.on (_stream_readable.js:772:35)
    at Ultron.on (/Users/klandsman/Sites/kaliber/velux/velux-always-on/node_modules/ultron/index.js:42:11)
    at WebSocket.setSocket (/Users/klandsman/Sites/kaliber/velux/velux-always-on/node_modules/ws/lib/WebSocket.js:131:18)
    at WebSocket.initAsServerClient (/Users/klandsman/Sites/kaliber/velux/velux-always-on/node_modules/ws/lib/WebSocket.js:465:8)
    at new WebSocket (/Users/klandsman/Sites/kaliber/velux/velux-always-on/node_modules/ws/lib/WebSocket.js:70:26)
    at WebSocketServer.completeUpgrade (/Users/klandsman/Sites/kaliber/velux/velux-always-on/node_modules/ws/lib/WebSocketServer.js:275:20)
    at WebSocketServer.handleUpgrade (/Users/klandsman/Sites/kaliber/velux/velux-always-on/node_modules/ws/lib/WebSocketServer.js:227:10)
    at Server.WebSocketServer._ultron.on (/Users/klandsman/Sites/kaliber/velux/velux-always-on/node_modules/ws/lib/WebSocketServer.js:86:14)
---------------------------------------------
    at Ultron.on (/Users/klandsman/Sites/kaliber/velux/velux-always-on/node_modules/ultron/index.js:42:11)
    at new WebSocketServer (/Users/klandsman/Sites/kaliber/velux/velux-always-on/node_modules/ws/lib/WebSocketServer.js:85:20)
    at startWebSocketServer (/Users/klandsman/Sites/kaliber/velux/velux-always-on/node_modules/@kaliber/build/webpack-plugins/websocket-communication-plugin.js:84:15)
    at <anonymous>
    at process._tickCallback (internal/process/next_tick.js:188:7)
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
error Command failed with signal "SIGTERM".
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
ERROR: "watch" exited with 1.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

[EECOLOR]

request/request#2161

[klaasman]

Temporary fix:

config/dev.js:

// Temporary fix, remove when https://github.com/kaliberjs/build/issues/106 is resolved
process.on('uncaughtException', (err) => { if (err.code !== 'ECONNRESET') throw err })

module.exports = { ... }

[dennispassway]

Will this be fixed?

[EECOLOR]

nodejs/node#14102 suggest a missing socket.on('error', handleError); might be the cause. However, nodejs/node#14102 shows that there is a more fundamental problem with nodejs itself.

websockets/ws#1256 suggests ws.on('error', () => console.log('errored')); It's unclear however if that is attached to the ws.Server instance.

We could however add a line in https://github.com/kaliberjs/build/blob/master/library/webpack-plugins/websocket-communication-plugin.js

const wss = new ws.Server({ port })
wss.on('error', () => ...)

Please try that on a machine where you can easily reproduce the problem and see if the error moves through that method.

A suggestion for a workaround in case that doesn't work, add the following to the client:

window.addEventListener('beforeunload', function () {
  ws.close();
});

Note that this only has effect on Chrome, but according to the reports Chrome > 63 is the browser affected most.

A related quote:

@endel the error is not a bug in the library and #1256 (comment) is the proof. The fact that it only happens on Chrome is another proof.

You get the error only on ws@>=3.3.3 because it is the first version that does not swallow the net.Socket errors.

More possible fixes (I think these are the most promising):

// Server example.
wss.on('connection', (ws) => {
  ws.on('error', (err) => {
    // Ignore network errors like `ECONNRESET`, `EPIPE`, etc.
    if (err.errno) return;
    throw err;
  });
});

// Client example.
const ws = new WebSocket(url);

ws.on('error', handleError);

Lastly (from websockets/ws#1256):

I didn't expect to create so much disruption by re-emitting net.Socket errors as I assumed that everyone already had 'error' listeners set up but I was wrong and it seems that these errors are ignored anyway, so I'm thinking to not re-emit them again, restoring behavior of ws@<=3.3.2.

[EECOLOR]

So yeah, I think we now have enough information to fix it. Let's test it next week.

[lpinca]

You definitely need an 'error' listener on the the WebSocket instance. Even if we decide to not re-emit the socket errors again, there are others errors that can be emitted.

Errors can also be emitted on the WebSocketServer instance (WebSocket.Server) but those are re-emitted from the underlying HTTP(S) server and unrelated to this bug report.

Don't use process.on('uncaughtException') as it causes more issues than it solves.