|
| 1 | +import json |
| 2 | +from asyncio import ( |
| 3 | + AbstractEventLoop, |
| 4 | + Semaphore, |
| 5 | + Task, |
| 6 | + gather, |
| 7 | + get_event_loop, |
| 8 | +) |
| 9 | +from collections.abc import ( |
| 10 | + AsyncIterator, |
| 11 | + Callable, |
| 12 | +) |
| 13 | +from contextlib import asynccontextmanager |
| 14 | +from dataclasses import dataclass, field |
| 15 | +from typing import Any, Protocol, Self |
| 16 | + |
| 17 | +from dishka import AsyncContainer |
| 18 | +from nats.aio.msg import Msg as NatsMessage |
| 19 | +from nats.errors import TimeoutError as NatsTimeoutError |
| 20 | +from nats.js import JetStreamContext |
| 21 | +from structlog.types import FilteringBoundLogger |
| 22 | + |
| 23 | +from ttt.entities.tools.assertion import not_none |
| 24 | +from ttt.infrastructure.dishka.next_container import NextContainer |
| 25 | +from ttt.infrastructure.structlog.logger import ( |
| 26 | + unexpected_error_log, |
| 27 | +) |
| 28 | + |
| 29 | + |
| 30 | +class PullSubscribe(Protocol): |
| 31 | + async def __call__( |
| 32 | + self, js: JetStreamContext, subject: str, |
| 33 | + ) -> JetStreamContext.PullSubscription: ... |
| 34 | + |
| 35 | + |
| 36 | +class NatsRemoteFuncBody[**PmT](Protocol): |
| 37 | + async def __call__( |
| 38 | + self, |
| 39 | + container: AsyncContainer, |
| 40 | + *args: PmT.args, |
| 41 | + **kwargs: PmT.kwargs, |
| 42 | + ) -> Any: ... # noqa: ANN401 |
| 43 | + |
| 44 | + |
| 45 | +@dataclass |
| 46 | +class NatsRemoteFunc[**PmT = ...]: |
| 47 | + body: NatsRemoteFuncBody[PmT] |
| 48 | + _pull_subscribe: PullSubscribe |
| 49 | + _subject: str |
| 50 | + |
| 51 | + _max_workers: int | None = None |
| 52 | + _pull_consume_batch: int | None = None |
| 53 | + _pull_consume_timeout: float | None = None |
| 54 | + |
| 55 | + _js: JetStreamContext = field(init=False) |
| 56 | + _pull_subscription: JetStreamContext.PullSubscription = field(init=False) |
| 57 | + _workers: set[Task[None]] = field(init=False, default_factory=set) |
| 58 | + _semaphore: Semaphore = field(init=False, default_factory=Semaphore) |
| 59 | + _container: AsyncContainer = field(init=False) |
| 60 | + _loop: AbstractEventLoop = field(init=False) |
| 61 | + |
| 62 | + @asynccontextmanager |
| 63 | + async def startup( |
| 64 | + self, |
| 65 | + js: JetStreamContext, |
| 66 | + max_workers: int | None = None, |
| 67 | + pull_consume_batch: int | None = None, |
| 68 | + pull_consume_timeout: float | None = None, |
| 69 | + ) -> AsyncIterator[Self]: |
| 70 | + self._loop = get_event_loop() |
| 71 | + self._max_workers = max_workers or self._max_workers or 1000 |
| 72 | + self._pull_consume_batch = ( |
| 73 | + pull_consume_batch or self._pull_consume_batch or 1 |
| 74 | + ) |
| 75 | + self._pull_consume_timeout = ( |
| 76 | + pull_consume_timeout or self._pull_consume_timeout or 5 |
| 77 | + ) |
| 78 | + |
| 79 | + self._js = js |
| 80 | + self._pull_subscription = await self._pull_subscribe( |
| 81 | + self._js, |
| 82 | + self._subject, |
| 83 | + ) |
| 84 | + self._semaphore = Semaphore(self._max_workers) |
| 85 | + |
| 86 | + try: |
| 87 | + yield self |
| 88 | + finally: |
| 89 | + await gather(*self._workers) |
| 90 | + |
| 91 | + async def __call__(self, *args: PmT.args, **kwargs: PmT.kwargs) -> None: |
| 92 | + payload = {"args": args, "kwargs": kwargs} |
| 93 | + |
| 94 | + await not_none(self._js).publish( |
| 95 | + self._subject, |
| 96 | + payload=json.dumps(payload).encode(), |
| 97 | + ) |
| 98 | + |
| 99 | + async def processor(self, next_container: NextContainer) -> None: |
| 100 | + while True: |
| 101 | + try: |
| 102 | + messages = await self._pull_subscription.fetch( |
| 103 | + batch=not_none(self._pull_consume_batch), |
| 104 | + timeout=self._pull_consume_timeout, |
| 105 | + ) |
| 106 | + except NatsTimeoutError: |
| 107 | + continue |
| 108 | + |
| 109 | + for message in messages: |
| 110 | + await self._create_worker(message, next_container) |
| 111 | + |
| 112 | + async def _create_worker( |
| 113 | + self, message: NatsMessage, next_container: NextContainer, |
| 114 | + ) -> None: |
| 115 | + await self._semaphore.acquire() |
| 116 | + task = self._loop.create_task(self._worker(message, next_container)) |
| 117 | + self._workers.add(task) |
| 118 | + task.add_done_callback(self._workers.discard) |
| 119 | + |
| 120 | + async def _worker( |
| 121 | + self, message: NatsMessage, next_container: NextContainer, |
| 122 | + ) -> None: |
| 123 | + async with next_container() as container: |
| 124 | + try: |
| 125 | + json_str = message.data.decode() |
| 126 | + json_ = json.loads(json_str) |
| 127 | + await self.body(container, *json_["args"], **json_["kwargs"]) |
| 128 | + except Exception as error: # noqa: BLE001 |
| 129 | + await message.nak() |
| 130 | + |
| 131 | + logger = await container.get(FilteringBoundLogger) |
| 132 | + await unexpected_error_log(logger, error) |
| 133 | + |
| 134 | + self._semaphore.release() |
| 135 | + except BaseException as error: |
| 136 | + await message.nak() |
| 137 | + self._semaphore.release() |
| 138 | + raise error from error |
| 139 | + else: |
| 140 | + await message.ack() |
| 141 | + self._semaphore.release() |
| 142 | + |
| 143 | + |
| 144 | +def nats_remote[**PmT]( |
| 145 | + subject: str, |
| 146 | + pull_subscribe: PullSubscribe, |
| 147 | + max_workers: int | None = None, |
| 148 | + pull_consume_batch: int | None = None, |
| 149 | + pull_consume_timeout: float | None = None, |
| 150 | +) -> Callable[[NatsRemoteFuncBody[PmT]], NatsRemoteFunc[PmT]]: |
| 151 | + def decorator(body: NatsRemoteFuncBody[PmT]) -> NatsRemoteFunc[PmT]: |
| 152 | + return NatsRemoteFunc( |
| 153 | + body, |
| 154 | + pull_subscribe, |
| 155 | + subject, |
| 156 | + max_workers, |
| 157 | + pull_consume_batch, |
| 158 | + pull_consume_timeout, |
| 159 | + ) |
| 160 | + |
| 161 | + return decorator |
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