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urbanLifeline/dify/api/libs/broadcast_channel/redis/sharded_channel.py

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2025-12-01 17:21:38 +08:00
from libs.broadcast_channel.channel import Producer, Subscriber, Subscription
from redis import Redis
from ._subscription import RedisSubscriptionBase
class ShardedRedisBroadcastChannel:
"""
Redis 7.0+ Sharded Pub/Sub based broadcast channel implementation.
Provides "at most once" delivery semantics using SPUBLISH/SSUBSCRIBE commands,
distributing channels across Redis cluster nodes for better scalability.
"""
def __init__(
self,
redis_client: Redis,
):
self._client = redis_client
def topic(self, topic: str) -> "ShardedTopic":
return ShardedTopic(self._client, topic)
class ShardedTopic:
def __init__(self, redis_client: Redis, topic: str):
self._client = redis_client
self._topic = topic
def as_producer(self) -> Producer:
return self
def publish(self, payload: bytes) -> None:
self._client.spublish(self._topic, payload) # type: ignore[attr-defined]
def as_subscriber(self) -> Subscriber:
return self
def subscribe(self) -> Subscription:
return _RedisShardedSubscription(
pubsub=self._client.pubsub(),
topic=self._topic,
)
class _RedisShardedSubscription(RedisSubscriptionBase):
"""Redis 7.0+ sharded pub/sub subscription implementation."""
def _get_subscription_type(self) -> str:
return "sharded"
def _subscribe(self) -> None:
assert self._pubsub is not None
self._pubsub.ssubscribe(self._topic) # type: ignore[attr-defined]
def _unsubscribe(self) -> None:
assert self._pubsub is not None
self._pubsub.sunsubscribe(self._topic) # type: ignore[attr-defined]
def _get_message(self) -> dict | None:
assert self._pubsub is not None
return self._pubsub.get_sharded_message(ignore_subscribe_messages=True, timeout=0.1) # type: ignore[attr-defined]
def _get_message_type(self) -> str:
return "smessage"