Trace and graph execution path for a method

trace_calls.rb

# Quick and dirty code to drop into a Rails controller to trace execution through code paths and graph it.
# Changing the conditional on line 10 allows you to tweak which classes/directories you see int he graph.
# The trace_calls method could also be used outside a controller like: trace_calls{ do_some_method }

    around_action :trace_calls
    def trace_calls
      g = GraphViz.new( :G, :type => :digraph )
      nodes = []
      trace = TracePoint.new(:call,:return) do |tp|
        if tp.path =~ /clickfunnels\/userpages/ #|| tp.path =~ /clickfunnels\/app/ #|| tp.path =~ /clickfunnels\/lib/
          method_name = "#{tp.defined_class}##{tp.method_id}"
          puts "nodes = #{nodes.length}"
          if tp.event == :call
            new_node = g.add_nodes(method_name)
            puts "call #{method_name}"
            old_node = nodes.last
            if new_node.present? && old_node.present?
              g.add_edges(old_node[:node], new_node)
            end
            nodes << { method_name: method_name, node: new_node }
          elsif tp.event == :return
            puts "return #{method_name}"
            old_node = nodes.last
            prev_node = nodes[-2]
            if old_node[:method_name] == method_name
              nodes.pop
            end
          end
        end
      end
      trace.enable
        yield
      trace.disable
      g.output( :png => "hello_world.png" )
    end