在 Airflow 的操作员参数中将 jinja 模板格式化为 INT [英] Format jinja template as INT in operator parameter in Airflow

问题描述

我正在尝试将 jinja 模板参数格式化为整数，以便我可以将其传递给需要 INT(可以是自定义或 PythonOperator)的运算符，但我无法做到.

I'm trying to format a jinja template parameter as an integer so I can pass it to an operator which expects INT (could be custom or PythonOperator) and I'm not able to.

请参阅下面的示例 DAG.我正在使用内置的 Jinja 过滤器 |int 但这不起作用 - 类型仍然是

See sample DAG below. I'm using the built-in Jinja filter | int but that's not working - the type remains <class 'str'>

我还是 Airflow 的新手，但根据我对 Jinja/Airflow 作品的了解，我认为这是不可能的.我看到了两种主要的解决方法:

I'm still new with Airflow but I don't think this is possible based on what I've read about Jinja/Airflow works. I see two main workarounds:

• 将运算符参数更改为期望字符串并处理下面的转换.
• 在 单独 PythonOperator 中处理此转换，该 PythonOperator 将字符串转换为 int 并使用 xcom/task 上下文导出该字符串.(我认为这会奏效，但不确定)

• Change the operator parameter to expect string and handle the conversion underneath.
• Handle this conversion in a separate PythonOperator which converts the string to an int and export that using xcom/task context. (I think this will work but not sure)

请告诉我任何其他解决方法

Please let me know of any other workarounds

def greet(mystr):
    print (mystr)
    print(type(mystr))

default_args = {
    'owner': 'airflow',
    'start_date': days_ago(2)        
}

dag = DAG(
    'template_dag',
    default_args=default_args,
    description='template',
    schedule_interval='0 13 * * *'
)


with dag:

    # foo = "{{ var.value.my_custom_var | int }}"  # from variable
    foo = "{{ execution_date.int_timestamp | int }}"  # built in macro

    # could be MyCustomOperator
    opr_greet = PythonOperator(task_id='greet',
                               python_callable=greet,
                               op_kwargs={'mystr': foo}
                               )

    opr_greet

气流 1.10.11

推荐答案

更新答案:

从 Airflow 2.1 开始，您可以将 render_template_as_native_obj=True 传递给 dag，Airflow 将返回 Python 类型(dict、int 等)而不是字符串.请参阅此拉取请求

As of Airflow 2.1, you can pass render_template_as_native_obj=True to the dag and Airflow will return the Python type (dict, int, etc) instead of string. See this pull request

dag = DAG(
    dag_id="example_template_as_python_object",
    schedule_interval=None,
    start_date=days_ago(2),
    render_template_as_native_obj=True,
)

以前版本的旧答案:

我发现了一个提供最佳解决方法的相关问题，IMO.

I found a related question that provides the best workaround, IMO.

Airflow xcom pull 只返回字符串

诀窍是使用 PythonOperator，在那里进行数据类型转换，然后使用参数调用主运算符.下面是将 json 字符串转换为 dict 对象的示例.同样可以申请string转int等

The trick is to use a PythonOperator, do the datatype conversion there and then call the main operator with the parameter. Below is an example in converting a json string to a dict object. Same can apply for converting string to int, etc.

def my_func(ds, **kwargs):
    ti = kwargs['ti']
    body = ti.xcom_pull(task_ids='privious_task_id')
    import_body= json.loads(body)
    op = CloudSqlInstanceImportOperator(
            project_id=GCP_PROJECT_ID,
            body= import_body,
            instance=INSTANCE_NAME,
            gcp_conn_id='postgres_default',
            task_id='sql_import_task',
            validate_body=True,
        )
    op.execute()
    

p = PythonOperator(task_id='python_task', python_callable=my_func)

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