dify/api/libs/broadcast_channel/redis/channel.py

93 lines
2.7 KiB
Python

from __future__ import annotations
from typing import Any, override
from extensions.redis_names import serialize_redis_name
from libs.broadcast_channel.channel import Producer, Subscriber, Subscription
from redis import Redis, RedisCluster
from ._subscription import RedisSubscriptionBase
class BroadcastChannel:
"""
Redis Pub/Sub based broadcast channel implementation (regular, non-sharded).
Provides "at most once" delivery semantics for messages published to channels
using Redis PUBLISH/SUBSCRIBE commands for real-time message delivery.
The `redis_client` used to construct BroadcastChannel should have `decode_responses` set to `False`.
"""
def __init__(
self,
redis_client: Redis | RedisCluster,
*,
join_timeout_ms: int = 2000,
):
self._client = redis_client
# See `RedisSubscriptionBase._join_timeout_ms`: how long close()
# waits for the listener thread before returning.
self._join_timeout_ms = max(int(join_timeout_ms or 0), 0)
def topic(self, topic: str) -> Topic:
return Topic(self._client, topic, join_timeout_ms=self._join_timeout_ms)
class Topic:
def __init__(
self,
redis_client: Redis | RedisCluster,
topic: str,
*,
join_timeout_ms: int = 2000,
):
self._client = redis_client
self._topic = topic
self._redis_topic = serialize_redis_name(topic)
self._join_timeout_ms = max(int(join_timeout_ms or 0), 0)
def as_producer(self) -> Producer:
return self
def publish(self, payload: bytes) -> None:
self._client.publish(self._redis_topic, payload)
def as_subscriber(self) -> Subscriber:
return self
def subscribe(self) -> Subscription:
return _RedisSubscription(
client=self._client,
pubsub=self._client.pubsub(),
topic=self._redis_topic,
join_timeout_ms=self._join_timeout_ms,
)
class _RedisSubscription(RedisSubscriptionBase):
"""Regular Redis pub/sub subscription implementation."""
@override
def _get_subscription_type(self) -> str:
return "regular"
@override
def _subscribe(self) -> None:
assert self._pubsub is not None
self._pubsub.subscribe(self._topic)
@override
def _unsubscribe(self) -> None:
assert self._pubsub is not None
self._pubsub.unsubscribe(self._topic)
@override
def _get_message(self) -> dict[str, Any] | None:
assert self._pubsub is not None
return self._pubsub.get_message(ignore_subscribe_messages=True, timeout=1)
@override
def _get_message_type(self) -> str:
return "message"