|
| 1 | +"""Provides RedisChannel and RedisConnector.""" |
| 2 | + |
| 3 | +from __future__ import annotations |
| 4 | + |
| 5 | +import asyncio |
| 6 | +import typing as _t |
| 7 | + |
| 8 | +from plugboard_schemas.connector import ConnectorMode |
| 9 | +from that_depends import Provide, inject |
| 10 | + |
| 11 | +from plugboard.connector.connector import Connector |
| 12 | +from plugboard.connector.serde_channel import SerdeChannel |
| 13 | +from plugboard.exceptions import ChannelClosedError |
| 14 | +from plugboard.utils import DI, depends_on_optional |
| 15 | + |
| 16 | + |
| 17 | +try: |
| 18 | + from redis.asyncio import Redis |
| 19 | + from redis.asyncio.client import PubSub |
| 20 | +except ImportError: # pragma: no cover |
| 21 | + pass |
| 22 | + |
| 23 | + |
| 24 | +class RedisChannel(SerdeChannel): |
| 25 | + """`RedisChannel` for sending and receiving messages via Redis.""" |
| 26 | + |
| 27 | + @depends_on_optional("redis") |
| 28 | + def __init__( |
| 29 | + self, |
| 30 | + *args: _t.Any, |
| 31 | + key: str, |
| 32 | + send_fn: _t.Optional[_t.Callable[[bytes], _t.Awaitable[None]]] = None, |
| 33 | + recv_fn: _t.Optional[_t.Callable[[], _t.Awaitable[bytes]]] = None, |
| 34 | + pubsub: _t.Optional[PubSub] = None, |
| 35 | + **kwargs: _t.Any, |
| 36 | + ) -> None: |
| 37 | + """Instantiates a `RedisChannel`. |
| 38 | +
|
| 39 | + Uses Redis to provide communication between components on different processes. |
| 40 | + Requires a Redis server to be running with the URL set in the `REDIS_URL` |
| 41 | + environment variable. |
| 42 | +
|
| 43 | + Args: |
| 44 | + key: The Redis key for the channel. |
| 45 | + send_fn: Optional; A callable for sending messages to the Redis channel. |
| 46 | + recv_fn: Optional; A callable for receiving messages from the Redis channel. |
| 47 | + pubsub: Optional; The Redis `PubSub` instance, used in pub-sub mode. |
| 48 | + """ |
| 49 | + super().__init__(*args, **kwargs) |
| 50 | + self._key = key |
| 51 | + self._send_fn = send_fn |
| 52 | + self._recv_fn = recv_fn |
| 53 | + self._pubsub = pubsub |
| 54 | + |
| 55 | + # Set initial state based on intended usage |
| 56 | + self._is_send_closed = send_fn is None |
| 57 | + self._is_recv_closed = recv_fn is None |
| 58 | + |
| 59 | + async def send(self, msg: bytes) -> None: |
| 60 | + """Send a message to the Redis channel.""" |
| 61 | + if self._is_send_closed or self._send_fn is None: |
| 62 | + raise ChannelClosedError("Channel is closed for sending") |
| 63 | + await self._send_fn(msg) |
| 64 | + |
| 65 | + async def recv(self) -> bytes: |
| 66 | + """Receive a message from the Redis channel.""" |
| 67 | + if self._is_recv_closed or self._recv_fn is None: |
| 68 | + raise ChannelClosedError("Channel is closed for receiving") |
| 69 | + return await self._recv_fn() |
| 70 | + |
| 71 | + async def close(self) -> None: |
| 72 | + """Closes the `RedisChannel`.""" |
| 73 | + # If we are a sender, send the close message (via super().close()) |
| 74 | + if not self._is_send_closed: |
| 75 | + await super().close() |
| 76 | + self._is_send_closed = True |
| 77 | + |
| 78 | + if self._pubsub is not None: |
| 79 | + await self._pubsub.unsubscribe() |
| 80 | + await self._pubsub.close() |
| 81 | + self._pubsub = None |
| 82 | + |
| 83 | + self._is_recv_closed = True |
| 84 | + |
| 85 | + |
| 86 | +class RedisConnector(Connector): |
| 87 | + """`RedisConnector` connects components via Redis.""" |
| 88 | + |
| 89 | + @depends_on_optional("redis") |
| 90 | + def __init__(self, *args: _t.Any, **kwargs: _t.Any) -> None: |
| 91 | + """Instantiates a `RedisConnector`. |
| 92 | +
|
| 93 | + Uses Redis to connect components via either pipeline (list-based) or pub-sub |
| 94 | + (channel-based) mode. Requires a Redis server to be running with the URL set |
| 95 | + in the `REDIS_URL` environment variable. |
| 96 | + """ |
| 97 | + super().__init__(*args, **kwargs) |
| 98 | + self._topic: str = ( |
| 99 | + str(self.spec.source) if self.spec.mode == ConnectorMode.PUBSUB else self.spec.id |
| 100 | + ) |
| 101 | + self._send_channel: _t.Optional[RedisChannel] = None |
| 102 | + self._send_channel_lock = asyncio.Lock() |
| 103 | + self._recv_channel: _t.Optional[RedisChannel] = None |
| 104 | + self._recv_channel_lock = asyncio.Lock() |
| 105 | + |
| 106 | + def __getstate__(self) -> dict: # pragma: no cover |
| 107 | + state = self.__dict__.copy() |
| 108 | + for attr in ("_send_channel", "_recv_channel", "_send_channel_lock", "_recv_channel_lock"): |
| 109 | + if attr in state: |
| 110 | + del state[attr] |
| 111 | + return state |
| 112 | + |
| 113 | + def __setstate__(self, state: dict) -> None: # pragma: no cover |
| 114 | + self.__dict__.update(state) |
| 115 | + self._send_channel = None |
| 116 | + self._send_channel_lock = asyncio.Lock() |
| 117 | + self._recv_channel = None |
| 118 | + self._recv_channel_lock = asyncio.Lock() |
| 119 | + |
| 120 | + @inject |
| 121 | + async def _get_key(self, job_id: str = Provide[DI.job_id]) -> str: |
| 122 | + return f"{job_id}.{self._topic}" |
| 123 | + |
| 124 | + @inject |
| 125 | + async def connect_send( |
| 126 | + self, redis_client: Redis | None = Provide[DI.redis_client] |
| 127 | + ) -> RedisChannel: |
| 128 | + """Returns a `RedisChannel` for sending messages.""" |
| 129 | + if redis_client is None: |
| 130 | + raise RuntimeError("Redis client not available. Ensure Redis URL is configured.") |
| 131 | + async with self._send_channel_lock: |
| 132 | + if self._send_channel is not None: |
| 133 | + return self._send_channel |
| 134 | + |
| 135 | + key = await self._get_key() |
| 136 | + send_fn = self._build_send_fn(redis_client, key) |
| 137 | + self._send_channel = RedisChannel(key=key, send_fn=send_fn) |
| 138 | + return self._send_channel |
| 139 | + |
| 140 | + def _build_send_fn( |
| 141 | + self, redis_client: Redis, key: str |
| 142 | + ) -> _t.Callable[[bytes], _t.Awaitable[None]]: |
| 143 | + if self.spec.mode == ConnectorMode.PIPELINE: |
| 144 | + |
| 145 | + async def send_fn(msg: bytes) -> None: |
| 146 | + await redis_client.lpush(key, msg) # type: ignore[misc] |
| 147 | + else: |
| 148 | + |
| 149 | + async def send_fn(msg: bytes) -> None: |
| 150 | + await redis_client.publish(key, msg) |
| 151 | + |
| 152 | + return send_fn |
| 153 | + |
| 154 | + @inject |
| 155 | + async def connect_recv( |
| 156 | + self, redis_client: Redis | None = Provide[DI.redis_client] |
| 157 | + ) -> RedisChannel: |
| 158 | + """Returns a `RedisChannel` for receiving messages.""" |
| 159 | + if redis_client is None: |
| 160 | + raise RuntimeError("Redis client not available. Ensure Redis URL is configured.") |
| 161 | + key = await self._get_key() |
| 162 | + if self.spec.mode == ConnectorMode.PIPELINE: |
| 163 | + async with self._recv_channel_lock: |
| 164 | + if self._recv_channel is not None: |
| 165 | + return self._recv_channel |
| 166 | + recv_fn = self._build_recv_fn(redis_client, key) |
| 167 | + channel = RedisChannel(key=key, recv_fn=recv_fn) |
| 168 | + self._recv_channel = channel |
| 169 | + else: # ConnectorMode.PUBSUB |
| 170 | + pubsub = redis_client.pubsub(ignore_subscribe_messages=True) |
| 171 | + await pubsub.subscribe(key) |
| 172 | + recv_fn = self._build_recv_fn(redis_client, key, pubsub=pubsub) |
| 173 | + channel = RedisChannel(key=key, recv_fn=recv_fn, pubsub=pubsub) |
| 174 | + return channel |
| 175 | + |
| 176 | + def _build_recv_fn( |
| 177 | + self, redis_client: Redis, key: str, pubsub: _t.Optional[PubSub] = None |
| 178 | + ) -> _t.Callable[[], _t.Awaitable[bytes]]: |
| 179 | + if self.spec.mode == ConnectorMode.PIPELINE: |
| 180 | + |
| 181 | + async def recv_fn() -> bytes: |
| 182 | + result = await redis_client.brpop([key], timeout=None) # type: ignore[misc] |
| 183 | + return result[1] |
| 184 | + else: |
| 185 | + if pubsub is None: |
| 186 | + raise ValueError("PubSub instance required for PUBSUB mode") |
| 187 | + |
| 188 | + async def recv_fn() -> bytes: |
| 189 | + # NOTE : We use `listen()` here due to non-sensical `get_message()` behaviour with |
| 190 | + # : `ignore_subscribe_messages=True`. |
| 191 | + # : See: https://github.com/redis/redis-py/issues/733#issuecomment-1956647495 |
| 192 | + message = await asyncio.wait_for(anext(pubsub.listen()), timeout=None) |
| 193 | + return message["data"] |
| 194 | + |
| 195 | + return recv_fn |
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