keyPrefix not applied for xgroup

[pgarrett-twc]

Hi, when I enable keyPrefix, the xgroup create command is not respecting the setting.

Minimal recreation:

const Redis = require('ioredis')
const conn = new Redis('127.0.0.1:6379', { keyPrefix: 'myprefix:' })
conn.on('ready', async () => {
  await conn.xgroup('CREATE', 'mystream', 'grp', '0', 'MKSTREAM')
  await conn.xreadgroup('GROUP', 'grp', 'cons', 'STREAMS', 'mystream', '>')
  await conn.quit()
})

This produces:

  ioredis:redis write command[127.0.0.1:6379]: 0 -> xgroup([ 'CREATE', 'mystream', 'grp', '0', 'MKSTREAM' ]) +1ms
  ioredis:redis write command[127.0.0.1:6379]: 0 -> xreadgroup([ 'GROUP', 'grp', 'cons', 'STREAMS', 'myprefix:mystream', '$' ]) +1ms

Note that the argument 'mystream' in the first command should be 'myprefix:mystream' like it is in the second command.

I think this might be related to #1591 and #1610. Although it doesn't look like @ioredis/commands 1.2.0 will fix the problem, because the commands.json config for xgroup looks wrong.

[pgarrett-twc]

To work around this problem, I use this function to wrap my keys before calling stream commands like xgroup, xinfo.

import { getKeyIndexes } from '@ioredis/commands'
const needKeyPrefixHack = getKeyIndexes('xgroup', ['CREATE', 'x', 'g', 0, 'MKSTREAM']).length == 0

export function getXgroupKey(k: string, redis: Redis | Cluster) {
  if (needKeyPrefixHack) {
    const prefix = redis.options?.keyPrefix
    return prefix == undefined ? k : `${prefix}${k}`
  } else {
    return k
  }
}

Another problem caused by xgroup not being fully supported is that, in cluster mode, it frequently receives a MOVED reply, which causes ioredis to refresh the slot cache as if the topology had changed. This caused a problem for me because I'm using AWS MemoryDB which occasionally responds slowly to CLUSTER SLOTS, so I was seeing ClusterAllFailedError.

So instead of calling redisConn.xgroup I am calling redisConn.sendCommand, which allows me to influence the original slot by providing getKeys:

import { Command } from 'ioredis'

if (needKeyPrefixHack) {
  const xgk = getXgroupKey(key, redisConn)
  const command = new Command('XGROUP', ['CREATE', xgk, consumerGroup, '0', 'MKSTREAM'], {
    replyEncoding: 'utf8',
  })
  command.getKeys = () => [xgk]
  redisConn.sendCommand(command)
  await command.promise
}
else {
  await redisConn.xgroup('CREATE', key, consumerGroup, 0, 'MKSTREAM')
}