Prefect流Python中的任务序列

Question

我目前正在使用Python Prefect (prefect.io)，我编写了下面的代码

from prefect import Flow, task
@task
def say_hello():
    print('Hello')

@task
def say_how_a_u():
    print('How are you?')

@task
def say_bye():
    print('Bye Bye')

with Flow('Test') as flow:
   say_hello()
   say_how_a_u()
   say_bye()

flow.run()

事实上，所有函数都是并行调用的。如何进行一个又一个的函数调用，等待前面的函数？你好-> how_a_u ->拜拜

我处理触发器，但失败了

Answer 1

您只需在流块期间指定上游依赖项。还有另一种语法可以找到这里

from prefect import Flow, task
@task
def say_hello():
    print('Hello')

@task
def say_how_a_u():
    print('How are you?')

@task
def say_bye():
    print('Bye Bye')

with Flow('Test') as flow:
   a = say_hello()
   b = say_how_a_u(upstream_tasks=[a])
   c = say_bye(upstream_tasks=[b])

flow.run()