Instrumentation support

[kushniryb]

Evening folks, hope you are well!

Would you be interested in adding instrumentation support to premailer-rails?

Recently I've been working on a small feature that relies on mail interception. I'm using premailer-rails to generate text parts for emails. I've had a hard time figuring out why emails intercepted by my custom interceptor had their text_part set to nil. I was using initializer file to register it and as it turned out, my interceptor was added before Premailer::Rails::Hook.

I thought it'd be cool if you could hook into premailer-rails initializaition process to ensure that your custom interceptors are registered after those defined by premailer-rails. Here's what I've in mind:

class Premailer
  module Rails
    class Railtie < ::Rails::Railtie
      ActiveSupport.on_load(:action_mailer) do
        ActiveSupport::Notifications.instrument("register_interceptors.premailer_rails") do
          ::Premailer::Rails.register_interceptors
        end
      end
    end
  end
end

# initializer
ActiveSupport::Notifications.subscribe "register_interceptors.premailer_rails" do
  ActionMailer::Base.register_interceptor(MyCustomInterceptor)
end

Is that something you'd be interested in?

Looking forward to you response,
Cheers!

[fphilipe]

@kushniryb, sounds like an interesting addition. Feel free to fire a PR 😊