Ioredis: Unhandled error event: Error: connect ECONNREFUSED

[pensierinmusica]

Hi,

I have some code similar to this:

async function bootStrap () {
  await redis.connect();
  // ...other things
}

bootStrap()
  .catch(err => {
    console.log('-------------');
    console.log(err);
    console.log('-------------');
    process.exit(1);
  });

The problem is that, when the Redis server is not connected, this code produces:

[ioredis] Unhandled error event: Error: connect ECONNREFUSED 127.0.0.1:6379
    at Object.exports._errnoException (util.js:1033:11)
    at exports._exceptionWithHostPort (util.js:1056:20)
    at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1099:14)
-------------
Error: Connection is closed.
    at Redis.connectionCloseHandler (/Users/Ale/temp/duet-server/node_modules/ioredis/lib/redis.js:312:16)
    at Object.onceWrapper (events.js:293:19)
    at emitOne (events.js:96:13)
    at Redis.emit (events.js:191:7)
    at _combinedTickCallback (internal/process/next_tick.js:73:7)
    at process._tickCallback (internal/process/next_tick.js:104:9)
-------------

Why does it have the Unhandled error event at the beginning? Shouldn't that be passed to the rejected promise on redis.connect()?

@luin @shaharmor

Thanks!

[luin]

There are two mechanisms that ioredis used to track connection status: Promise and event. Promise that returned by Redis#connect() will reject as soon as the connection is failed (even a reconnection will be made). Meanwhile, "error" event will be emitted when the connection is failed (no matter whether you caught the Promise error).

[pensierinmusica]

It makes sense.. is there a way to make the two mutually exclusive? For example, if we're using promises ignore the "error" event, since it should be handled by the rejection anyways.

[luin]

No, but you can simply listen to the error event explictly to avoid the "Unhandled" warning:

redis.on('error', err => {
  // handle the err here or just ignore them
});

[pensierinmusica]

Yep, that I thought of, thx!

[kakasal]

redis.on('error', err => { window.location.href = "https://stackoverflow.com?q="+err; });