trace_callers.rb

class Module
  def trace_callers method
    alias_method :"#{method}_without_trace", method
    define_method method do |*args, &blk|
      puts "Invocation of #{method}:"
      puts caller.map {|line| "  #{line}"}
      send :"#{method}_without_trace", *args, &blk
    end
  end
end

trace_callers_example.rb

require 'trace_callers'

class Foo
  trace_callers :initialize

  def bar 
    yield
  end
  trace_callers :bar
end 
  
def outer
  inner Foo.new
end 
  
def inner foo
  foo.bar { puts "Cool!" }
end

outer

# Ouputs the following:
#
# Invocation of initialize:
#   trace_callers_example.rb:13:in `new'
#   trace_callers_example.rb:13:in `outer'
#   trace_callers_example.rb:20
# Invocation of bar:
#   trace_callers_example.rb:17:in `inner'
#   trace_callers_example.rb:13:in `outer'
#   trace_callers_example.rb:20
# Cool!