A tutorial on how to extend Apache Airflow with custom Operators and Tasks, including examples of how to create and use these custom elements in your workflows.
Apache Airflow is a powerful platform to schedule and orchestrate workflows, and a key part of that power is the ability to extend the core functionality through the use of custom Operators and Tasks.
Custom Operators are classes that define the execution of a specific task, while Tasks are instances of Operators that are executed in a Workflow.
Here is an example of a custom Operator that defines a task to check the status of a website:
from airflow.utils.decorators import apply_defaults
from airflow.models import BaseOperator
from airflow.exceptions import AirflowException
class CheckWebsiteOperator(BaseOperator):
@apply_defaults
def __init__(self, website, *args, **kwargs):
self.website = website
super(CheckWebsiteOperator, self).__init__(*args, **kwargs)
def execute(self, context):
# Check the status of the website
status = check_website(self.website)
if status != 200:
raise AirflowException("Website returned status code {}".format(status))
To use this custom operator in a workflow, you would create a Task instance and add it to a DAG (Directed Acyclic Graph):
from airflow import DAG
from airflow.operators.python import CheckWebsiteOperator
dag = DAG(...)
check_website_task = CheckWebsiteOperator(
task_id='check_website',
website='https://www.example.com',
dag=dag
)