单一工做流的执行➕回滚框架初步想法（基于事件驱动模式）

思路来源： 事件驱动框架。

 

Part 1. 定义一个框架 event_flow.py  (须要再改动）

 1 #! /usr/bin/env python
 2 
 3 
 4 deploy_phase_list = []  5 
 6 def deploy():  7     for phase in deploy_phase_list:  8         phase_obj = phase()  9  phase_obj.deploy() 10 
11 
12 def rollback(): 13     for phase in reversed(deploy_phase_list): 14         phase_obj = phase() 15  phase_obj.rollback() 16 
17 
18 class BasePhase(object): 19     def deploy(): 20         raise Exception("deploy() must be overwrite") 21 
22     def rollback(): 23         raise Exception("rollback() must be overwrite")

event base frame

// 此处能够考虑➕装饰器，当deploy  顺利完成，才把该类append 到rollback list 

 

Part 2. 使用该框架

 

#! /usr/bin/env python

import event_flow

class MyFirstStep(event_flow.BasePhase):
    def deploy():
        print("Do First Step to deploy")

    def rollback():
        print("Rollback First Step")



class MySecondStep(event_flow.BasePhase):
    def deploy():
        print("Do Second Step to deploy")

    def rollback():
        print("Nothing to rollback")
        pass


class MyThirdStep(event_flow.BasePhase):
    def deploy():
        print("Do Third Step to deploy")

    def rollback():
        print("Rollback third Step")


if __name__ == "__main__":
    event_flow.deploy_phase_list.append(MyFirstStep, MySecondStep, MyThirdStep)
    try:
        event_flow.deploy()
    exception Exception as e:
        event_flow.rollback()

　　

 

可是该方法给能够完成单一工做流的部署以及回滚。后续的这种单一工做流，能够参考这种模式进行开发。

其中各个步骤的返回等数据交互，须要借助第三方（例如数据库等）