Source code for tests.system.apache.kafka.kafka_message_queue_trigger

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from __future__ import annotations

import json

# [START howto_trigger_message_queue]
from airflow.providers.common.messaging.triggers.msg_queue import MessageQueueTrigger
from airflow.providers.standard.operators.empty import EmptyOperator
from airflow.sdk import DAG, Asset, AssetWatcher



[docs]
def apply_function(message):
    val = json.loads(message.value())
    print(f"Value in message is {val}")
    return True



# Define a trigger that listens to an external message queue (Apache Kafka in this case)

[docs]
trigger = MessageQueueTrigger(
    queue="kafka://localhost:9092/test",
    apply_function="kafka_message_queue_trigger.apply_function",
)


# Define an asset that watches for messages on the queue

[docs]
asset = Asset("kafka_queue_asset", watchers=[AssetWatcher(name="kafka_watcher", trigger=trigger)])


with DAG(dag_id="example_kafka_watcher", schedule=[asset]) as dag:
    EmptyOperator(task_id="task")
# [END howto_trigger_message_queue]


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)