问题描述
在定义一个函数以供以后用作python_callable时，为什么将'ds'作为函数的第一个参数？
While defining a function to be later used as a python_callable, why is 'ds' included as the first arg of the function?
例如：
def python_func(ds, **kwargs):
pass
我查看了Airflow文档，但找不到任何解释。
I looked into the Airflow documentation, but could not find any explanation.
推荐答案
这与 provide_context = True 参数有关。根据Airflow文档，
This is related to the provide_context=True parameter. As per Airflow documentation,
ds 是这些关键字参数之一，并以 YYYY-MM-DD。对于在文档中标记为（模板）的参数，可以使用’{{ds}}’默认变量来传递执行日期。您可以在此处阅读有关默认变量的更多信息：
ds is one of these keyword arguments and represents execution date in format "YYYY-MM-DD". For parameters that are marked as (templated) in the documentation, you can use '{{ ds }}' default variable to pass the execution date. You can read more about default variables here:
（已淘汰）
PythonOperator没有模板化参数，所以要做类似
PythonOperator doesn't have templated parameters, so doing something like
python_callable=print_execution_date('{{ ds }}')
不起作用。要在PythonOperator的可调用函数中打印执行日期，您将必须执行以下操作：
won't work. To print execution date inside the callable function of your PythonOperator, you will have to do it as
def print_execution_date(ds, **kwargs):
print(ds)
或
def print_execution_date(**kwargs):
print(kwargs.get('ds'))
希望这会有所帮助。
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