在一个使用 rails 的项目中，有这么一个类，做的事情就是动态创建一个 job，来给别的系统发消息

class JobSender
  def self.mail(from:, to:, event:, message:)
    Register.find_job(from, to, event).class.perform_later(*message)
  end

  class Job < Struct.new(:name, :queue);
    def class
      begin
        self.name.constantize
      rescue NameError => e
        create_job
        retry
      end
    end

  private

    def create_job
      eval code
    end

    def code
      <<-JOB
        class #{self.name} < ActiveJob::Base
          queue_as :"#{self.queue}"
          def perform(*args); end
        end
      JOB
    end
  end

  class Register
    def self.find_job(sender, receiver, event)
      job_config = Settings.job_sender[sender][receiver][event]
      Job.new(job_config[:name], job_config[:queue])
    rescue NoMethodError
      raise "JobSender #{sender}:#{receiver}:#{event} does not registered."
    end
  end
end

settings.yml

job_sender:
  server_1:
    server_2:
      hello:
        name: HelloJob
        queue: test_queue

执行下面的代码，可以正确发送消息

JobSender.mail(from: :server_1, to: :server_2, event: :hello, message: "hello")

然而下面的代码会死循环

JobSender::Job.new("HelloJob", "test_queue").class.perform_later("hello")

这是为什么呢？

我主要不明白为什么前面的代码能够正确发送消息