ActiveSupport::Notifications thread safety demo

frobnicate.rb

#!/usr/bin/env ruby

require 'active_support'

class Frobnicator
  def frobnicate
    ActiveSupport::Notifications.instrument('frobnicate') do
      puts 'frobnicating'
    end
  end
end

ActiveSupport::Notifications.subscribe('frobnicate') do |name, start, finish, id, payload|
  raise "uh-oh, start was nil" if start == nil
end

nthreads = 16
iterations = 10000
threads = []

nthreads.times do |i|
  threads << Thread.new do
    Thread.current.abort_on_exception = true
    frobnicator = Frobnicator.new
    iterations.times do |j|
      frobnicator.frobnicate
    end
  end
end

threads.each(&:join)