Flask 浣滆€?Armin Ronacher锛氭垜涓嶈寰楁湁寮傛鍘嬪姏

Posted 2021-04-12 Python鐚?/a> Fl

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鑻辨枃 | I'm not feeling the async pressure

鍘熶綔 | Armin Ronacher锛?020.01.01

璇戣€?/strong> | 璞岃眴鑺变笅鐚獲Python鐚?/span>

澹版槑 锛?/span> 鏈炕璇戝熀浜?/span> CC BY-NC-SA 4.0 鎺堟潈鍗忚锛屽唴瀹圭暐鏈夋敼鍔紝杞浇璇蜂繚鐣欏師鏂囧嚭澶勶紝璇峰嬁鐢ㄤ簬鍟嗕笟鎴栭潪娉曠敤閫斻€?/span>

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浠€涔堟槸鑳屽帇

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绯熺硶鐨勯粯璁ゆ柟寮?/span>

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from asyncio import start_server, run

async def on_client_connected(reader, writer):
    while True:
        data = await reader.readline()
        if not data:
            break
        writer.write(data)

async def server():
    srv = await start_server(on_client_connected, '127.0.0.1', 8888)
    async with srv:
        await srv.serve_forever()

run(server())

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writer.write(data)
await writer.drain()

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绛夊緟涓庣瓑寰呯潃绛夊緟

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鍥犳锛岃繖鏄ぉ鐪熺殑鐗堟湰锛屾垜浠彧鐭ラ亾鑷繁鍦ㄧ瓑寰咃細

from asyncio.sync import Semaphore

semaphore = Semaphore(200)

async def handle_request(request):
    await semaphore.acquire()
    try:
        return generate_response(request)
    finally:
        semaphore.release()

瀵逛簬 handle_request 寮傛鍑芥暟鐨勮皟鐢ㄨ€咃紝鎴戜滑鍙兘鐪嬪埌鎴戜滑姝ｅ湪绛夊緟骞朵笖浠€涔堥兘娌℃湁鍙戠敓銆傛垜浠湅涓嶅埌鏄洜涓鸿繃杞借€屽湪绛夊緟锛岃繕鏄洜涓虹敓鎴愬搷搴旈渶鑺辫垂寰堥暱鏃堕棿鑰屽湪绛夊緟銆傚熀鏈笂锛屾垜浠竴鐩村湪杩欓噷缂撳啿锛岀洿鍒版湇鍔″櫒鏈€缁堣€楀敖鍐呭瓨骞跺穿婧冦€?/p>

杩欐槸鍥犱负鎴戜滑娌℃湁鍏充簬鑳屽帇鐨勬矡閫氭笭閬撱€傞偅涔堟垜浠皢濡備綍瑙ｅ喅鍛紵涓€绉嶉€夋嫨鏄坊鍔犱竴涓腑闂村眰銆傜幇鍦ㄤ笉骞哥殑鏄紝杩欓噷鐨?asyncio 淇″彿閲忔病鏈夌敤锛屽洜涓哄畠鍙細璁╂垜浠瓑寰呫€備絾鏄亣璁炬垜浠彲浠ヨ闂俊鍙烽噺杩樺墿涓嬪灏戜釜浠ょ墝锛岄偅涔堟垜浠彲浠ユ墽琛岀被浼艰繖鏍风殑鎿嶄綔锛?/p>

from hypothetical_asyncio.sync import Semaphore, Service

semaphore = Semaphore(200)

class RequestHandlerService(Service):
    async def handle(self, request):
        await semaphore.acquire()
        try:
            return generate_response(request)
        finally:
            semaphore.release()

    @property
    def is_ready(self):
        return semaphore.tokens_available()

鐜板湪锛屾垜浠绯荤粺鍋氫簡涓€浜涙洿鏀广€傜幇鍦紝鎴戜滑鏈変竴涓?RequestHandlerService锛屽叾涓寘鍚簡鏇村淇℃伅銆傜壒鍒槸瀹冨叿鏈変簡鍑嗗灏辩华鐨勬蹇点€傝鏈嶅姟鍙互琚闂槸鍚﹀噯澶囧氨缁€傝鎿嶄綔鍦ㄦ湰璐ㄤ笂鏄棤闃诲鐨勶紝骞朵笖鏄渶浣充及閲忋€?/p>

鐜板湪锛岃皟鐢ㄨ€呬細灏嗚繖涓細

response = await handle_request(request)

鍙樻垚杩欎釜锛?/p>

request_handler = RequestHandlerService()
if not request_handler.is_ready:
    response = Response(status_code=503)
else:
    response = await request_handler.handle(request)

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鏁版嵁娴佸拰鍗忚

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鐩稿叧閾炬帴

[1] I'm not feeling the async pressure: https://lucumr.pocoo.org/2020/1/1/async-pressure/

[2] CC BY-NC-SA 4.0: https://creativecommons.org/licenses/by-nc-sa/4.0/

[3] Backpressure explained 鈥?the resisted flow of data through software: https://medium.com/@jayphelps/backpressure-explained-the-flow-of-data-through-software-2350b3e77ce7

[4] 娴侀噺鎺у埗: https://en.wikipedia.org/wiki/Flow_control_(data)

[5] tower: https://github.com/tower-rs/tower

[6] actix-service: https://docs.rs/actix-service/

[7] hyper-h2: https://github.com/python-hyper/hyper-h2

[8] 鏂囦欢涓婁紶鏈嶅姟鍣ㄧず渚? https://python-hyper.org/projects/h2/en/stable/curio-example.html

[9] Dask: https://dask.org/

[10] 鑳屽帇: https://github.com/dask/distributed/issues/2602

[11] 鍏充簬缁欐墍鏈夋枃浠剁郴缁烮O娣诲姞淇″彿閲? https://github.com/golang/go/issues/7903

[12] 鏈変竴涓棶棰樺彲杩芥函鍒?016骞达紝: https://github.com/aio-libs/aiohttp/issues/1368

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