lib_sidekiq_cli.rb

    def write_pid
      if path = options[:pidfile]
        pidfile = File.expand_path(path)
        `logger -t sidekiq-runner "Writing #{::Process.pid} to #{pidfile}"`
        File.open(pidfile, 'w') do |f|
          f.puts ::Process.pid
        end

        sleep 1
        unless File.exist?(pidfile)
          `logger -t 'sidekiq-runner' "#{pidfile} no longer exists after being written"`
          raise "The pidfile doesn't exist after I wrote it"
        end
      end
    end