Do not merge controller back in

[liaden]

If a user defines a default_tag :controller, nil, then it cause the metrics to use event.payload[:controller] which is "ApplicationController" instead of "application".

[liaden]

Note: excluding is only rails 6+.

[Envek]

Oh, now it is obvious that we need to exclude all keys that we manually set in. Please try something like this:

Suggested change

	}.merge!(event.payload.slice(*Yabeda.default_tags.keys.excluding(:controller)))
	}
	labels.merge!(event.payload.slice(*Yabeda.default_tags.keys - labels.keys))

[liaden]

Optionally, I'd prefer there be a Yabeda::Rails.extra_tags = [:my, :custom, :tags], and it adds those tags to the metrics that are defined instead of the tags instead of requiring a globally polluting default_tag that affects other gems that may be included as well.

[Envek]

Hey! Thank you for your PR!

Can you please tell more about your use case? Default tags are meant to be really application-global (both collected by gems and user-defined in the application code)

And just a note that current behavior was added in #13 by @raivil (maybe it will shed some light)

[liaden]

Can you please tell more about your use case? Default tags are meant to be really application-global (both collected by gems and user-defined in the application code)

From the readme, we have to both do a default_tag call as well as the append_info_to_payload to pass it through. My thought was the extra_tags could be splatted onto all the metrics that are defined by yabeda-rails to avoid the label being applied to everything. I don't think this matters since yabeda-rb/yabeda#16 would allow for the app to define the labels without having to add complexity to this gem.

[Envek]

default_tag is needed only because some adapters (well, only prometheus at the moment) requires us to declare beforehand what tags every metric can have. So it is kind of hack.

[Envek]

Released in 0.7.2

Thank you!