Support a SOURCE_PREFIX option

[nextmat]

For users who are using the library with multiple apps on a single Librato account currently the only way to differentiate them is to use PREFIX to split them into separate metrics.

If we supported a SOURCE_PREFIX then metrics for all applications could be reported into the same metrics with different sources and users could leverage dynamic instruments to switch between them without having to build new instruments & dashboards.

[jeffblake]

Bump....

For example, I prefix all my sources by:

[environment].[process_type].server.worker

e.g.

production.web.1.10

This way I can have a single Librato account and use it for both staging and production environments.

[josephruscio]

@jeffblake thanks for bumping this. We actually did recently add support for this through a separate gem, librato-rack-source_prefix, and neglected to update this ticket or the README.

You should be able to just add that gem and set your custom prefixes. Let us know if you need any help and I'll leave this ticket open for now as a reminder that we need to update the README.

[jeffblake]

Thanks Joseph. I came up with this shortly before your comment,

production:
  user: <%= ENV['LIBRATO_USER'] %>
  token: <%= ENV['LIBRATO_TOKEN'] %>
  source: <%= ENV['LIBRATO_SOURCE'] + '.' + ENV['DYNO'] %>

This seemed like the easiest way to take care of the automatic rails and rack instrumentation. I already wrap other calls to Librato in a small class... so I don't think I'll need librato-rack-source_prefix

[jeffblake]

In fact, it would be nice to use the librato-rack-source_prefix gem, as I use other gems that integrate Librato reporting, however it does not support the Heroku ENV['DYNO'] name. So it seems that we need another source prefix to compliment LIBRATO_SOURCE and source_pids. This way we could set

LIBRATO_SOURCE=production
LIBRATO_SERVER_PREFIX= ENV['DYNO'] = web.1 or whatever

and then are concatenated together.

edit: maybe this request is too platform specific and I am best off using my above config file to customize the source. I will still use librato-rack-source_prefix gem to compliment

[josephruscio]

@jeffblake thanks for the feedback. I'll check in with @bdehamer next week on the best way to support Heroku with this :)