Source code for airflow.example_dags.example_asset_with_watchers

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"""
Example DAG for demonstrating the usage of event driven scheduling using assets and triggers.
"""

from __future__ import annotations

import os
import tempfile

from airflow.decorators import task
from airflow.models.baseoperator import chain
from airflow.models.dag import DAG
from airflow.providers.standard.triggers.file import FileTrigger
from airflow.sdk.definitions.asset import Asset

[docs]file_path = tempfile.NamedTemporaryFile().name

with DAG(
    dag_id="example_create_file",
    catchup=False,
):

    @task
[docs]    def create_file():
        with open(file_path, "w") as file:
            file.write("This is an example file.\n")

    chain(create_file())

[docs]trigger = FileTrigger(filepath=file_path, poke_interval=10)
[docs]asset = Asset("example_asset", watchers=[trigger])

with DAG(
    dag_id="example_asset_with_watchers",
    schedule=[asset],
    catchup=False,
):

    @task
[docs]    def delete_file():
        if os.path.exists(file_path):
            os.remove(file_path)  # Delete the file

    chain(delete_file())