Prefect Flow 中的任务序列 Python

Question

我目前正在使用 Python 框架 - Prefect (prefect.io) 我写了下面的代码

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()

事实是所有函数都是并行调用的。如何一个接一个地调用函数并等待前一个函数？你好 -> how_a_u -> 再见

我使用触发器，但它失败了

Answer 1

您可以在 Flow 块中指定上游依赖项。您可以找到另一种语法 here

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()

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