Monitor a queue's message inflow/outflow

debug_queue.rb

require 'io/console/size'

# Usage: Replace a Queue.new with DebugQueue.new(Queue.new)

class DebugQueue < SimpleDelegator
  def <<(*msg, trace: caller_locations(3, 3))
    debug_print("<<", msg, trace)
    super(*msg)
  end

  def pop(trace: caller_locations(3, 3))
    super().tap do |msg|
      debug_print(">>", msg, trace)
    end
  end

  private

  def debug_print(direction, msg, trace)
    msg = msg.to_s
    msg =
      if msg.size > msg_width
        msg[0..msg_width] + "..."
      else
        msg
      end

    $stdout.puts(
      <<~MSG
        #{direction} | #{msg}
          trace: #{trace.join(",\n" + " " * 9)}
      MSG
    )
  end

  def msg_width
    # prevent msg from overflow to another line
    @msg_width ||= (IO.console_size[1] - 10)
  end
end

Perhaps it could also use a name attribute when there're multiple queues?