delayed job profiling

delayed_job.rb

# config/initializer/delayed_job.rb

module Delayed
  module Plugins
    class Flaming < Plugin
      callbacks do |lifecycle|
        lifecycle.around(:invoke_job) do |job, *args, &block|
          HelperMethods.flaming(name: "DELAYEDJOB--#{job.name}") do
            block.call(job, *args)
          end
        end
      end
    end
  end
end

Delayed::Worker.plugins << Delayed::Plugins::Flaming if ENV['WITH_FLAME']

helper.rb

def flaming(name: "flame", filters: [Rails.root.to_s, ".html.haml"])
  require 'flamegraph'
  require 'stackprof'

  return yield if @aflame

  @aflame = true
  result = nil

  start_time = Time.now
  end_time = nil
  exception = nil

  html = Flamegraph.generate(nil, js_include_filters: filters) do
    begin
      result = yield
      end_time = Time.now
    rescue => e
      exception = e
    end
  end

  time_taken = (end_time || Time.now) - start_time
  dir = Rails.root.join("tmp/flames").tap(&:mkpath)
  file_name = dir.join "#{Time.now}--#{name}".parameterize + "--#{time_taken}.html"

  File.write(file_name, html)

  @aflame = nil
  raise exception if exception

  result
end