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Cluster UnhandledPromiseRejectionWarning

See original GitHub issue

I’m intentionally causing a connection error (by omitting a NAT mapping for one cluster node) to verify my application’s error handling, but I’m seeing an UnhandledPromiseRejectionWarning:

(node:18) UnhandledPromiseRejectionWarning: Error: Connection is closed.
    at close (/home/node/app/node_modules/ioredis/built/redis/event_handler.js:102:25)
    at Socket.<anonymous> (/home/node/app/node_modules/ioredis/built/redis/event_handler.js:73:20)
    at Object.onceWrapper (events.js:288:20)
    at Socket.emit (events.js:200:13)
    at Socket.EventEmitter.emit (domain.js:471:20)
    at TCP.<anonymous> (net.js:586:12)

My code is executing a multi command like this:

redisClient
      .multi()
      .expire(key, this.expire)
      .hgetall(key)
      .exec()
      .then(
        async ([[expErr, expVal], [hashErr, hashVal]]) => {
          if (expErr || hashErr) {
            throw expErr || hashErr;
          }
          return Object.values(hashVal);
        },
      )
      .then(x => cb(null, x))
      .catch(err => cb(err, []));

I believe this is the relevant debug output preceding the throw:

  ioredis:redis status[127.0.0.1:7000]: [empty] -> wait +5ms
  ioredis:delayqueue send 1 commands in failover queue +119ms
  ioredis:redis status[127.0.0.1:7000]: wait -> connecting +1ms
  ioredis:redis queue command[127.0.0.1:7000]: 0 -> multi([]) +1ms
  ioredis:redis queue command[127.0.0.1:7000]: 0 -> expire([ 'mykey', '2592000' ]) +0ms
  ioredis:redis queue command[127.0.0.1:7000]: 0 -> hgetall([ 'mykey' ]) +0ms
  ioredis:redis queue command[127.0.0.1:7000]: 0 -> exec([]) +1ms
  ioredis:connection error: Error: connect ECONNREFUSED 127.0.0.1:7000
    at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1054:14) {
  errno: 'ECONNREFUSED',
  code: 'ECONNREFUSED',
  syscall: 'connect',
  address: '127.0.0.1',
  port: 7000
} +9ms
  ioredis:redis status[127.0.0.1:7000]: connecting -> close +2ms
  ioredis:connection skip reconnecting because `retryStrategy` is not a function +1ms
  ioredis:redis status[127.0.0.1:7000]: close -> end +0ms

The promise for exec does reject as expected (json taken from my log):

{
  "type": "Error",
  "message": "Connection is closed.",
  "stack": "Error: Connection is closed.\n    at close (/home/node/app/node_modules/ioredis/built/redis/event_handler.js:102:25)\n    at Socket.<anonymous> (/home/node/app/node_modules/ioredis/built/redis/event_handler.js:73:20)\n    at Object.onceWrapper (events.js:288:20)\n    at Socket.emit (events.js:200:13)\n    at Socket.EventEmitter.emit (domain.js:471:20)\n    at TCP.<anonymous> (net.js:586:12)",
  "previousErrors": [
    {
      "previousErrors": "[Circular]"
    },
    {
      "previousErrors": "[Circular]"
    },
    {
      "previousErrors": "[Circular]"
    }
  ]
}

Is there something I can do to catch the rejection?

Possibly related, the 'error' event listener I have attached to the cluster does not trigger when this happens, which also seems unexpected.

I was using 4.9.0 and tried updating to 4.9.5, and have the same experience with both versions.

TIA for any guidance!

Issue Analytics

State:
Created 4 years ago
Comments:13 (8 by maintainers)

Top GitHub Comments

1reaction

luincommented, Jun 8, 2019

Thanks for providing the minimal reproduction, it’ve been a great help. I created a pr to solve the issue: https://github.com/luin/ioredis/pull/884. Still writing tests for it.

0reactions

abhijeetbadouriyacommented, Jun 29, 2019

This is error we are getting