cli.rb

module ReportCli
  class Runner

    include Concurrent::Async
    
    attr_accessor :threads_num, :run_times, :caller

    def initialize
      @conn = Config.connection
    end

    # TODO use TPoolexecutor to limit queue ,
    # http://ruby-concurrency.github.io/concurrent-ruby/Concurrent/ThreadPoolExecutor.html

    def run
      pool = Concurrent::FixedThreadPool.new(self.threads_num)
      
      @instance = self
      
      pool.post{ 
        @instance.run_times.times{ 
          @instance.caller.exec 
        } 

      }
      pool.wait_for_termination
      
    end

    def call
      puts "sending reports"
      self.caller.send_report
    end

  end

end

example.rb

      runner  = PreyReportCli::Runner.new
      runner.threads_num = 5
      runner.run_times = 5
      runner.caller = PreyReportCli::Report.new
      runner.run

report.rb

module ReportCli
  class Report
    
    def initialize
      @conn = Config.connection
    end

    def end_point
      "/api/v2/devices/#{Config.device_key}/reports.json"
    end

    def exec
      payload = {}
      payload[:screenshot] = Faraday::UploadIO.new("./#{shuffled_images}.jpg", 'image/jpeg')
      @conn.post end_point, payload
    end

    def shuffled_images
      ["mat","pic","van"].shuffle.first
    end

  end

end

@michelson Please take a look at this: https://gist.github.com/jdantonio/baf400950605e7e01f36