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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.
"""
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_interval='@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)
