trace methods

tracer.rb

def trace_calls_on
  scope = {}
  trace = TracePoint.new(:call, :line) do |tp|
    case tp.event
    when :call then puts "#{tp.path}:#{tp.lineno} #{tp.defined_class}::#{tp.method_id} " \
                         "called from #{scope[:path]}:#{scope[:lineno]} #{scope[:class]}::#{scope[:method_id]}"
    when :line then scope = {
                      event: :line,
                      lineno: tp.lineno,
                      path: tp.path,
                      class: tp.defined_class,
                      method_id: tp.method_id
                    }
    end
  end

  trace.enable
  yield
  trace.disable
end



require 'open-uri'

trace_calls_on do
  open('http://google.com', proxy: nil)
end

from http://confreaks.tv/videos/eurucamp2015-deep-diving-how-to-explore-a-new-code-base

credit @toch

another potential implementation: http://matt.aimonetti.net/posts/2013/03/05/inspecting-rails-4-request-dispatch-using-ruby-2-dot-0/