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}