A wrapper around tracing that is easier to use and lets you filter what you want.

tracer.rb

class Tracer

  Trace = Struct.new(:event, :file, :line, :id, :binding, :klass)

  def initialize(filename, params = {})
    @filename = filename
    @enabled = false

    @classes = params.fetch(:classes) { [/.*/] }
    @files = params.fetch(:files) { [/.*/] }

    @classes = Array(@classes)
    @files = Array(@files)

    open_trace_file
    set_handler
  end

  def enabled?
    @enabled
  end

  def enable
    @enabled = true
  end

  def disable
    @enabled = false
  end

  private

  attr_reader :filename, :trace_file, :classes, :files

  def on_trace(trace)
    if enabled? && is_class_method?(trace) && matches?(trace)
      log trace
    end
  end

  def set_handler
    set_trace_func proc { |event, file, line, id, binding, klass|
      on_trace Trace.new(event, file, line, id, binding, klass)
    }
  end

  def log(trace)
    trace_file.puts "#{trace.file}:#{trace.line} #{trace.klass}##{trace.id}"
  end

  def is_class_method?(trace)
    trace.event == 'call' && trace.klass.is_a?(::Class)
  end

  def matches?(trace)
    classes.any? { |pattern| pattern === trace.klass.to_s }
  end

  def open_trace_file
    @trace_file = open(filename, 'w')
  end

end

tracer_example.rb

tracer = Tracer.new 'trace.txt', classes: /active|postgis/i
tracer.enable

# write some code