airflow_18_ex_email_on_failure.py

from datetime import datetime, timedelta
from airflow import DAG
from airflow import utils
from airflow.operators import BashOperator, EmailOperator, DummyOperator

default_args = {
    'owner': 'myowner',
    'depends_on_past': False,
    'start_date': datetime(year=2017, month=10, day=18, hour=0, minute=0),
    'email': ['me@example.com'],
    'email_on_failure': True,
    'email_on_retry': False,
    'retries': 0,
    'retry_delay': timedelta(minutes=10),
    'execution_timeout': timedelta(hours=2)
}
params = {
    'script': './run.sh',
    'jar': '/path/to/my.jar',
    'class': 'com.example.MyApp',
    'memory_overhead': '1024',
    'executor_cores': '4',
    'num_executors': '4',
    'driver_memory': '2g',
    'executor_memory': '15g',
    'master': 'yarn',
    'deploy_mode': 'client',
    'queue': 'myqueue',
    'log_config_file': '/path/to/log4j.properties',
    'spark_home': '/path/to/spark2-client/bin',
    'proxy_user': 'myproxyuser',
    'spark_port_max_retries': 64
}
ventures = ['']
dag_id = "my_dag_id"
dag = DAG(
    dag_id,
    default_args=default_args,
    schedule_interval='15 * * * * ', #hourly, 15th minute
)
globals()[dag_id] = dag
tasks = []
for v in ventures:
    params['venture'] = v
    prefix = dag_id + '_' + v
    task_id = prefix + '_task'
    task = BashOperator(
        task_id=task_id,
        bash_command=params['script'],
        params=params,
        dag=dag,
        trigger_rule='all_done'
    )
    email = EmailOperator(
        task_id='email_' + v,
        dag=dag,
        to=email_recipients,
        subject="FAIL {{ task_instance_key_str }} {{ execution_date }}",
        html_content="Error message<br>{{ task_instance_key_str }}<br>{{ execution_date }}",
        trigger_rule='one_failed',
        queue='myqueue'
    )
    task >> email
    tasks.append(task)
# Add dummy as last task
# Workaround for https://issues.apache.org/jira/browse/AIRFLOW-1296
dummy = DummyOperator(
    task_id='last',
    dag=dag
)
tasks.append(dummy)
# Run tasks in order
for i, t in enumerate(tasks):
    if (i != 0):
        tasks[i].set_upstream(tasks[i - 1])