Source code for tests.system.google.cloud.pubsub.example_pubsub_deferrable
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"""
Example Airflow DAG that uses Google PubSub services.
"""
from __future__ import annotations
import os
from datetime import datetime
from airflow.models.dag import DAG
from airflow.providers.google.cloud.operators.pubsub import (
PubSubCreateSubscriptionOperator,
PubSubCreateTopicOperator,
PubSubDeleteSubscriptionOperator,
PubSubDeleteTopicOperator,
PubSubPublishMessageOperator,
)
from airflow.providers.google.cloud.sensors.pubsub import PubSubPullSensor
from airflow.utils.trigger_rule import TriggerRule
[docs]ENV_ID = os.environ.get("SYSTEM_TESTS_ENV_ID", "default")
[docs]PROJECT_ID = os.environ.get("SYSTEM_TESTS_GCP_PROJECT", "default")
[docs]TOPIC_ID = f"topic-{DAG_ID}-{ENV_ID}"
[docs]MESSAGE = {"data": b"Tool", "attributes": {"name": "wrench", "mass": "1.3kg", "count": "3"}}
with DAG(
DAG_ID,
schedule="@once", # Override to match your needs
start_date=datetime(2021, 1, 1),
catchup=False,
) as dag:
[docs] create_topic = PubSubCreateTopicOperator(
task_id="create_topic", topic=TOPIC_ID, project_id=PROJECT_ID, fail_if_exists=False
)
subscribe_task = PubSubCreateSubscriptionOperator(
task_id="subscribe_task", project_id=PROJECT_ID, topic=TOPIC_ID
)
publish_task = PubSubPublishMessageOperator(
task_id="publish_task",
project_id=PROJECT_ID,
topic=TOPIC_ID,
messages=[MESSAGE, MESSAGE],
)
subscription = subscribe_task.output
# [START howto_operator_gcp_pubsub_pull_message_with_async_sensor]
pull_messages_async = PubSubPullSensor(
task_id="pull_messages_async",
ack_messages=True,
project_id=PROJECT_ID,
subscription=subscription,
deferrable=True,
)
# [END howto_operator_gcp_pubsub_pull_message_with_async_sensor]
unsubscribe_task = PubSubDeleteSubscriptionOperator(
task_id="unsubscribe_task",
project_id=PROJECT_ID,
subscription=subscription,
)
unsubscribe_task.trigger_rule = TriggerRule.ALL_DONE
delete_topic = PubSubDeleteTopicOperator(task_id="delete_topic", topic=TOPIC_ID, project_id=PROJECT_ID)
delete_topic.trigger_rule = TriggerRule.ALL_DONE
(
create_topic
>> subscribe_task
>> publish_task
>> pull_messages_async
>> unsubscribe_task
>> delete_topic
)
# Task dependencies created via `XComArgs`:
# subscribe_task >> pull_messages_async
# subscribe_task >> unsubscribe_task
# ### Everything below this line is not part of example ###
# ### Just for system tests purpose ###
from tests_common.test_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_common.test_utils.system_tests 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)