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"""
Example Airflow DAG that creates and deletes Queues and creates, gets, lists,
runs and deletes Tasks in the Google Cloud Tasks service in the Google Cloud.
"""
from __future__ import annotations
import os
from datetime import datetime, timedelta
from google.api_core.retry import Retry
from google.cloud.tasks_v2.types import Queue
from google.protobuf import timestamp_pb2
from airflow import models
from airflow.decorators import task
from airflow.models.baseoperator import chain
from airflow.providers.google.cloud.operators.tasks import (
CloudTasksQueueCreateOperator,
CloudTasksQueueDeleteOperator,
CloudTasksTaskCreateOperator,
CloudTasksTaskDeleteOperator,
CloudTasksTaskGetOperator,
CloudTasksTaskRunOperator,
CloudTasksTasksListOperator,
)
from airflow.utils.trigger_rule import TriggerRule
[docs]ENV_ID = os.environ.get("SYSTEM_TESTS_ENV_ID")
[docs]DAG_ID = "cloud_tasks_tasks"
[docs]timestamp = timestamp_pb2.Timestamp()
timestamp.FromDatetime(datetime.now() + timedelta(hours=12))
[docs]LOCATION = "europe-central2"
# queue cannot use recent names even if queue was removed
[docs]QUEUE_ID = f"queue-{ENV_ID}-{DAG_ID.replace('_', '-')}"
[docs]TASK_NAME = "task-to-run"
[docs]TASK = {
"app_engine_http_request": { # Specify the type of request.
"http_method": "POST",
"relative_uri": "/example_task_handler",
"body": b"Hello",
},
"schedule_time": timestamp,
}
with models.DAG(
dag_id=DAG_ID,
schedule="@once",
start_date=datetime(2021, 1, 1),
catchup=False,
tags=["example", "tasks"],
) as dag:
@task(task_id="random_string")
[docs] def generate_random_string():
"""
Generate random string for queue and task names.
Queue name cannot be repeated in preceding 7 days and
task name in the last 1 hour.
"""
import random
import string
return "".join(random.choices(string.ascii_uppercase + string.digits, k=8))
random_string = generate_random_string()
create_queue = CloudTasksQueueCreateOperator(
location=LOCATION,
task_queue=Queue(stackdriver_logging_config=dict(sampling_ratio=0.5)),
queue_name=QUEUE_ID + "{{ task_instance.xcom_pull(task_ids='random_string') }}",
retry=Retry(maximum=10.0),
timeout=5,
task_id="create_queue",
)
delete_queue = CloudTasksQueueDeleteOperator(
location=LOCATION,
queue_name=QUEUE_ID + "{{ task_instance.xcom_pull(task_ids='random_string') }}",
task_id="delete_queue",
)
delete_queue.trigger_rule = TriggerRule.ALL_DONE
# [START create_task]
create_task = CloudTasksTaskCreateOperator(
location=LOCATION,
queue_name=QUEUE_ID + "{{ task_instance.xcom_pull(task_ids='random_string') }}",
task=TASK,
task_name=TASK_NAME + "{{ task_instance.xcom_pull(task_ids='random_string') }}",
retry=Retry(maximum=10.0),
timeout=5,
task_id="create_task_to_run",
)
# [END create_task]
# [START tasks_get]
tasks_get = CloudTasksTaskGetOperator(
location=LOCATION,
queue_name=QUEUE_ID + "{{ task_instance.xcom_pull(task_ids='random_string') }}",
task_name=TASK_NAME + "{{ task_instance.xcom_pull(task_ids='random_string') }}",
task_id="tasks_get",
)
# [END tasks_get]
# [START run_task]
run_task = CloudTasksTaskRunOperator(
location=LOCATION,
queue_name=QUEUE_ID + "{{ task_instance.xcom_pull(task_ids='random_string') }}",
task_name=TASK_NAME + "{{ task_instance.xcom_pull(task_ids='random_string') }}",
task_id="run_task",
)
# [END run_task]
# [START list_tasks]
list_tasks = CloudTasksTasksListOperator(
location=LOCATION,
queue_name=QUEUE_ID + "{{ task_instance.xcom_pull(task_ids='random_string') }}",
task_id="list_tasks",
)
# [END list_tasks]
# [START delete_task]
delete_task = CloudTasksTaskDeleteOperator(
location=LOCATION,
queue_name=QUEUE_ID + "{{ task_instance.xcom_pull(task_ids='random_string') }}",
task_name=TASK_NAME + "{{ task_instance.xcom_pull(task_ids='random_string') }}",
task_id="delete_task",
)
# [END delete_task]
chain(
random_string, create_queue, create_task, tasks_get, list_tasks, run_task, delete_task, delete_queue
)
from tests.system.utils.watcher import watcher
# This test needs watcher in order to properly mark success/failure
# when "tearDown" task with trigger rule is part of the DAG
list(dag.tasks) >> watcher()
from tests.system.utils import get_test_run # noqa: E402
# Needed to run the example DAG with pytest (see: tests/system/README.md#run_via_pytest)
[docs]test_run = get_test_run(dag)
