Source code for airflow.providers.apache.kafka.queues.kafka
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from __future__ import annotations
import re
from typing import TYPE_CHECKING
from urllib.parse import urlparse
from airflow.providers.apache.kafka.triggers.await_message import AwaitMessageTrigger
from airflow.providers.common.messaging.providers.base_provider import BaseMessageQueueProvider
if TYPE_CHECKING:
from airflow.triggers.base import BaseEventTrigger
# [START queue_regexp]
[docs]
QUEUE_REGEXP = r"^kafka://"
# [END queue_regexp]
[docs]
class KafkaMessageQueueProvider(BaseMessageQueueProvider):
"""
Configuration for Apache Kafka integration with common-messaging.
It uses the ``kafka://`` URI scheme for identifying Kafka queues.
**URI Format**:
.. code-block:: text
kafka://<broker>/<topic_list>
Where:
* ``broker``: Kafka brokers (hostname:port)
* ``topic_list``: Comma-separated list of Kafka topics to consume messages from
**Examples**:
.. code-block:: text
kafka://localhost:9092/my_topic
**Required kwargs**:
* ``apply_function``: Function to process each Kafka message
You can also provide ``topics`` directly in kwargs instead of in the URI.
.. code-block:: python
from airflow.providers.common.messaging.triggers.msg_queue import MessageQueueTrigger
trigger = MessageQueueTrigger(
queue="kafka://localhost:9092/test",
apply_function="module.apply_function",
)
For a complete example, see:
:mod:`tests.system.common.messaging.kafka_message_queue_trigger`
"""
[docs]
def queue_matches(self, queue: str) -> bool:
return bool(re.match(QUEUE_REGEXP, queue))
[docs]
def trigger_class(self) -> type[BaseEventTrigger]:
return AwaitMessageTrigger # type: ignore[return-value]
[docs]
def trigger_kwargs(self, queue: str, **kwargs) -> dict:
if "apply_function" not in kwargs:
raise ValueError("apply_function is required in KafkaMessageQueueProvider kwargs")
# [START extract_topics]
# Parse the queue URI
parsed = urlparse(queue)
# Extract topics (after host list)
# parsed.path starts with a '/', so strip it
raw_topics = parsed.path.lstrip("/")
topics = raw_topics.split(",") if raw_topics else []
# [END extract_topics]
if not topics and "topics" not in kwargs:
raise ValueError(
"topics is required in KafkaMessageQueueProvider kwargs or provide them in the queue URI"
)
return {} if "topics" in kwargs else {"topics": topics}