Allow to exclude paths from Rack

[noma4i]

Main reason we need to exclude paths is the crazy amount of health checks or metrics flooding telegraf. Option for exclude_paths will prevent reporting on that endpoints

[leshik]

Thanks @noma4i. @jgraichen could you take a look at this, please? Ref #24

[jgraichen]

Thank you, @noma4i and @leshik!

Would it be an option for you to generalize that into a exclude: argument that takes a lambda as an argument so that this gem doesn't need to know about paths?

For example:

# Return `true` to skip the metric point for this request
my_filter = lambda { |env|
  req = Rack::Request.new(env)
  req.path =~ %r{^/(health|metric)} || req.params['admin'] == '1'
}

use ::Telegraf::Rack.new(series: 'rack', agent: agent, tags: {global: 'tag'}, exclude: my_filter)

You wouldn't be limited to path filters only and the gem wouldn't need an update to support other filters.

[noma4i]

It looks too explicit for rails.

[franzliedke]

This gem (and especially this config) isn't focused on Rails.

[noma4i]

This gem is very less code to support.

[jgraichen]

@noma4i I haven't had enough time to review again in the last few days, sorry!

Are you no longer interested in pursuing this merge request?

[noma4i]

WoW that was fast. This PR was closed so fast that I was not able to fix anything. Just wow.

[jgraichen]

@noma4i You closed the PR yourself last week. That's why I was asking. :grin: