Airflow - 如何使EmailOperator html_content动态化？

Question

我正在寻找一种方法,允许动态设置给定EmailOperator任务发送的电子邮件内容.理想情况下,我想使电子邮件内容取决于xcom调用的结果,最好是通过html_content参数.

alert = EmailOperator(
    task_id=alertTaskID,
    to='please@dontreply.com',
    subject='Airflow processing report',
    html_content='raw content #2',
    dag=dag
)

我注意到Airflow文档说xcom调用可以嵌入到模板中.也许有一种方法可以在指定的任务ID上使用模板来制定xcom pull,然后将结果作为html_content传递？谢谢

Answer 1

使用PythonOperator+send_email代替：

from airflow.operators import PythonOperator
from airflow.utils.email import send_email


def email_callback(**kwargs):
    with open('/path/to.html') as f:
        content = f.read()
    send_email(
        to=[
            # emails
        ],
        subject='subject',
        html_content=content,
    )


email_task = PythonOperator(
    task_id='task_id',
    python_callable=email_callback,
    provide_context=True,
    dag=dag,
)

Answer 2

不妨自己回答这个问题.事实证明,使用模板+ xcom路线非常简单.此代码段在已定义的dag的上下文中工作.它使用BashOperator而不是EmailOperator,因为它更容易测试.

def pushparam(param, ds, **kwargs):
    kwargs['ti'].xcom_push(key='specificKey', value=param)
    return 

loadxcom = PythonOperator(
    task_id='loadxcom',
    python_callable=pushparam,
    provide_context=True,        
    op_args=['your_message_here'],
    dag=dag)

template2 = """
    echo "{{ params.my_param }}"
    echo "{{ task_instance.xcom_pull(task_ids='loadxcom', key='specificKey') }}"
"""
t5 = BashOperator(
    task_id='tt2',
    bash_command=template2,
    params={'my_param': 'PARAMETER1'},
    dag=dag)

可以使用以下内容在命令行上进行测试:

airflow test dag_name loadxcom 2015-12-31
airflow test dag_name tt2 2015-12-31

我最终将使用EmailOperator测试并在此处添加一些内容,如果它不起作用...

Answer 3

对于那些寻找使用带有EmailOperator的jinja模板的确切示例的人来说,这里有一个

from airflow.operators.email_operator import EmailOperator
from datetime import timedelta, datetime

email_task = EmailOperator(
    to='some@email.com',
    task_id='email_task',
    subject='Templated Subject: start_date {{ ds }}',
    params={'content1': 'random'},
    html_content="Templated Content: content1 - {{ params.content1 }}  task_key - {{ task_instance_key_str }} test_mode - {{ test_mode }} task_owner - {{ task.owner}} hostname - {{ ti.hostname }}",
    dag=dag)

您可以使用测试运行上面的代码段

airflow test dag_name email_task 2017-05-10