Implements Carbon namespacing

[alindeman]

statsd supports namespacing. For instance with a global namespace of stats and a counter namespace of counters, all counters would be namespaced as stats.counters.foo.

This PR implements statsd's namespacing logic (except for legacy namespacing, which I don't think we should be encouraging) in brubeck. Namespacing is not enabled by default, but can be configured in config.json.

Feedback welcomed 💚

[blak3r2]

For what it's worth, I have tested this pull request and it worked for me.

If you want to use carbon-namespacing then add the following options to your backend type carbon:

      "global_prefix" : "stats",
      "prefix_counter" : "counters",
      "prefix_timer" : "timers",
      "prefix_histo" : "histos",
      "prefix_gauge" : "gauges"

[eugenepaniot]

+1

[StevenACoffman]

@vmg @carlosmn this works for us as well. Merge?

[ghost]

Is this dead? :)

[vmg]

Generally speaking, we don't merge any features which we don't actively use in GitHub because we're afraid of unexpected side effects. This PR looks correct, however. If you really need this feature I'd advise you to carry this patch on a fork of brubeck.

[haggy]

we don't merge any features which we don't actively use in GitHub because we're afraid of unexpected side effects

@vmg Why even bother open sourcing this then?