enhancement(statsd source): add support for Unix datagram sockets in statsd source

[ianneub]

Summary

This PR adds an optional configuration option to the StatsD source to choose the type of Unix socket to use. Stream (by default) or Datagram. It also adds an optional configuration option to set the max_length of the UDP datagram to receive.

Vector configuration

data_dir: /var/lib/vector
sources:
  statsd:
    type: statsd
    mode: unix
    socket_type: datagram
    path: /tmp/statsd.sock
sinks:
  console:
    type: console
    inputs:
      - statsd
    encoding:
      codec: json

How did you test this PR?

I added test that is nearly a duplicate of the existing test for the unix stream socket. I also did manual testing by writting a small ruby file to invest StatsD data using the Datagram protocol.

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the no-changelog label to this PR.

References

Notes

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[github-actions]

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[ianneub]

I have read the CLA Document and I hereby sign the CLA