TypeError: undefined is not a function

[shaharmor]

Hi,
Using ioredis 1.7.6, we observed the following issue.
It probably happens if for some reason the response received from redis is incorrect (maybe timed out).
You should add a check that the response exists and is correct?

TypeError: undefined is not a function
    at /var/www/XXX/node_modules/YYY/node_modules/ioredis/lib/cluster.js:471:34
    at run (/var/www/XXX/node_modules/YYY/node_modules/ioredis/lib/utils/index.js:151:16)
    at tryCatcher (/var/www/XXX/node_modules/YYY/node_modules/ioredis/node_modules/bluebird/js/main/util.js:26:23)
    at Promise.successAdapter (/var/www/XXX/node_modules/YYY/node_modules/ioredis/node_modules/bluebird/js/main/nodeify.js:23:30)
    at Promise._settlePromiseAt (/var/www/XXX/node_modules/YYY/node_modules/ioredis/node_modules/bluebird/js/main/promise.js:575:21)
    at Promise._settlePromises (/var/www/XXX/node_modules/YYY/node_modules/ioredis/node_modules/bluebird/js/main/promise.js:693:14)
    at Async._drainQueue (/var/www/XXX/node_modules/YYY/node_modules/ioredis/node_modules/bluebird/js/main/async.js:123:16)
    at Async._drainQueues (/var/www/XXX/node_modules/YYY/node_modules/ioredis/node_modules/bluebird/js/main/async.js:133:10)
    at Immediate.Async.drainQueues [as _onImmediate] (/var/www/XXX/node_modules/YYY/node_modules/ioredis/node_modules/bluebird/js/main/async.js:15:14)
    at processImmediate [as _immediateCallback] (timers.js:367:17)

[luin]

Could you please post the result of command cluster slots?

[shaharmor]

there you go:

127.0.0.1:6379> cluster slots
1) 1) (integer) 5461
   2) (integer) 10922
   3) 1) "127.0.0.1"
      2) (integer) 6379
   4) 1) "10.240.56.139"
      2) (integer) 6380
2) 1) (integer) 0
   2) (integer) 5460
   3) 1) "10.240.29.254"
      2) (integer) 6379
   4) 1) "10.240.78.46"
      2) (integer) 6380
3) 1) (integer) 10923
   2) (integer) 16383
   3) 1) "10.240.56.139"
      2) (integer) 6379
   4) 1) "10.240.29.254"
      2) (integer) 6380

I think the issue happened when the cluster was not in its OK state, maybe during promotion or some other state

[AVVS]

This looks like the issue I had during the tests, and it was already fixed in the modern versions of ioredis

[shaharmor]

But the issue is at this line:
https://github.com/luin/ioredis/blob/1.7.6/lib/cluster.js#L471
meaning there was no error, and the result just became not as it should.

I don't see any check of the response in the master branch

[luin]

That's strange. It seems that redis guarantees cluster slots returns a nested array so that items should be an array. Could you print the result of cluster slots that ioredis gets when this error happens?

[shaharmor]

It doesn't happen anymore, it only happened last night during a cluster failover.

[luin]

Just checked the source code of cluster slots command: https://github.com/antirez/redis/blob/unstable/src/cluster.c#L3737. Haven't find out why items is not an array. Anyway, let me know if the error happens again.

@AVVS Are you able to reproduce the error (using the 1.7.6 version)?

[AVVS]

Thought was related to #56, but doesn't seem to be. Either way that was when cluster wasn't yet initialized and not all slots were allocated yet. In the recent versions I haven't seen it once and can't really try 1.7.6 at this point - these test sets are long gone 👎

[shaharmor]

I'm not sure its related to redis.
I think that there was something in the connection, maybe load on the server, on redis, timeout, network issue, or something like that.

[shaharmor]

I believe this can be closed as i have yet to witness it again using the latest version