Source code for airflow.providers.redis.sensors.redis_pub_sub
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from __future__ import annotations
from functools import cached_property
from typing import TYPE_CHECKING, Sequence
from airflow.providers.redis.hooks.redis import RedisHook
from airflow.sensors.base import BaseSensorOperator
if TYPE_CHECKING:
from airflow.utils.context import Context
[docs]class RedisPubSubSensor(BaseSensorOperator):
"""
Redis sensor for reading a message from pub sub channels.
:param channels: The channels to be subscribed to (templated)
:param redis_conn_id: the redis connection id
"""
[docs] template_fields: Sequence[str] = ("channels",)
def __init__(self, *, channels: list[str] | str, redis_conn_id: str, **kwargs) -> None:
super().__init__(**kwargs)
self.channels = channels
self.redis_conn_id = redis_conn_id
@cached_property
[docs] def pubsub(self):
hook = RedisHook(redis_conn_id=self.redis_conn_id).get_conn().pubsub()
hook.subscribe(self.channels)
return hook
[docs] def poke(self, context: Context) -> bool:
"""
Check for message on subscribed channels and write to xcom the message with key ``message``.
An example of message ``{'type': 'message', 'pattern': None, 'channel': b'test', 'data': b'hello'}``
:param context: the context object
:return: ``True`` if message (with type 'message') is available or ``False`` if not
"""
self.log.info("RedisPubSubSensor checking for message on channels: %s", self.channels)
message = self.pubsub.get_message()
self.log.info("Message %s from channel %s", message, self.channels)
# Process only message types
if message and message["type"] == "message":
context["ti"].xcom_push(key="message", value=message)
self.pubsub.unsubscribe(self.channels)
return True
return False