4.1 AWEL Lifecycle

Task Lifecycle Hooks

Task lifecycle hooks are a set of methods that can be implemented in a task to perform actions at different stages of the task lifecycle. The following hooks are available:

• before_dag_run: Execute before DAG run
• after_dag_end: Execute after DAG end

Example

Create a new file lifecycle_hooks.py in the awel_tutorial directory and add the following code:

import asyncio
from dbgpt.core.awel import DAG, MapOperator

class MyLifecycleTask(MapOperator[str, str]):
    async def before_dag_run(self):
        print("Before DAG run")

    async def after_dag_end(self):
        print("After DAG end")

    async def map(self, x: str) -> str:
        return f"Hello, {x}!"

with DAG("awel_lifecycle_hooks") as dag:
    task = MyLifecycleTask()

print(asyncio.run(task.call("world")))

And run the following command to execute the code:

poetry run python awel_tutorial/lifecycle_hooks.py

And the main output should look like this:

Before DAG run
After DAG end
Hello, world!