Error: send EINVAL ::1:8125 on Node.js 17+

[francisdb]

hot-shots 9.0.0
Darwin foobar.local 21.4.0 Darwin Kernel Version 21.4.0: Fri Mar 18 00:46:32 PDT 2022; root:xnu-8020.101.4~15/RELEASE_ARM64_T6000 arm64

we configure StatsD by default with host localhost

on Node.js 16 everything works as expected
on Node.js 17 and 18 we get:

 Unhandled error. (Error: Error sending hot-shots message: Error: send EINVAL ::1:8125

      at handleCallback (node_modules/hot-shots/lib/statsd.js:350:32)
      at processTicksAndRejections (node:internal/process/task_queues:81:21) {
        code: 'EINVAL'
      })
      at handleCallback (node_modules/hot-shots/lib/statsd.js:367:21)

Probably because localhost now resolves to ::1 instead of 127.0.0.1 and the code path expects an ipv4 address?

workaround is to configure 127.0.0.1 instead of localhost

[bdeitte]

Well, that's interesting. I'm surprised this isn't coming up with more people. Switching away from localhost just happened in version 8.0.0 and was done for performance reasons: #186

[jcarvalho]

We're seeing the same issue running in a IPv6 EKS Cluster, where the Dogstatsd agent running in the Node only has an IPv6 address.

We're working around this with the following snippet:

  udpSocketOptions: {
    type: process.env.DD_AGENT_HOST != null && isIPv6(process.env.DD_AGENT_HOST) ? "udp6" : "udp4",
  },

It would be great to have hot-shots auto-detect if an IPv6 is provided and change the Socket Type to udp6.