使用 pytest 测试时，如何使用 worker >= 2 干净地终止 Uvicorn + FastAPI 应用程序

Question

我有一个用 Uvicorn + FastAPI 编写的应用程序。我正在使用 PyTest 测试响应时间。

参考，我写了测试。但是，当 workers >= 2.

完成测试后，我发现应用程序还活着

我想在测试结束时干净利落地终止应用进程。

你有什么想法吗？

详情如下

环境

Windows 10
Bash 4.4.23 (https://cmder.net/)
python 3.7.5

图书馆

fastapi == 0.68.0
uvicorn == 0.14.0
请求 == 2.26.0
pytest == 6.2.4

示例代码

申请：main.py

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def hello_world():
    return "hello world"

测试：test_main.py

from multiprocessing import Process
import pytest
import requests
import time
import uvicorn

HOST = "127.0.0.1"
PORT = 8765
WORKERS = 1


def run_server(host: str, port: int, workers: int, wait: int = 15) -> Process:
    proc = Process(
        target=uvicorn.run,
        args=("main:app",),
        kwargs={
            "host": host,
            "port": port,
            "workers": workers,
        },
    )
    proc.start()
    time.sleep(wait)
    assert proc.is_alive()
    return proc


def shutdown_server(proc: Process):
    proc.terminate()
    for _ in range(5):
        if proc.is_alive():
            time.sleep(5)
        else:
            return
    else:
        raise Exception("Process still alive")


def check_response(host: str, port: int):
    assert requests.get(f"http://{host}:{port}").text == '"hello world"'


def check_response_time(host: str, port: int, tol: float = 1e-2):
    s = time.time()
    requests.get(f"http://{host}:{port}")
    e = time.time()
    assert e-s < tol


@pytest.fixture(scope="session")
def server():
    proc = run_server(HOST, PORT, WORKERS)
    try:
        yield
    finally:
        shutdown_server(proc)


def test_main(server):
    check_response(HOST, PORT)
    check_response_time(HOST, PORT)
    check_response(HOST, PORT)
    check_response_time(HOST, PORT)

执行结果

$ curl http://localhost:8765
curl: (7) Failed to connect to localhost port 8765: Connection refused
$ pytest test_main.py
=============== test session starts =============== platform win32 -- Python 3.7.5, pytest-6.2.4, py-1.10.0, pluggy-0.13.1
rootdir: .\
collected 1 item

test_main.py .                                                                                                                                                                                                                         [100%]

=============== 1 passed in 20.23s ===============
$ curl http://localhost:8765
curl: (7) Failed to connect to localhost port 8765: Connection refused
$ sed -i -e "s/WORKERS = 1/WORKERS = 3/g" test_main.py
$ curl http://localhost:8765
curl: (7) Failed to connect to localhost port 8765: Connection refused
$ pytest test_main.py
=============== test session starts =============== platform win32 -- Python 3.7.5, pytest-6.2.4, py-1.10.0, pluggy-0.13.1
rootdir: .\
collected 1 item

test_main.py .                                                                                                                                                                                                                         [100%]

=============== 1 passed in 20.21s ===============
$ curl http://localhost:8765
"hello world"

$ # Why is localhost:8765 still alive?

Answer 1

我自己找到了解决方法。

谢谢 >

解决方案

通过 pip install psutil 安装 psutil 后，更新 test_main.py

from multiprocessing import Process
import psutil
import pytest
import requests
import time
import uvicorn

HOST = "127.0.0.1"
PORT = 8765
WORKERS = 3


def run_server(host: str, port: int, workers: int, wait: int = 15) -> Process:
    proc = Process(
        target=uvicorn.run,
        args=("main:app",),
        kwargs={
            "host": host,
            "port": port,
            "workers": workers,
        },
    )
    proc.start()
    time.sleep(wait)
    assert proc.is_alive()
    return proc


def shutdown_server(proc: Process):

    ##### SOLUTION #####
    pid = proc.pid
    parent = psutil.Process(pid)
    for child in parent.children(recursive=True):
        child.kill()
    ##### SOLUTION END ####

    proc.terminate()
    for _ in range(5):
        if proc.is_alive():
            time.sleep(5)
        else:
            return
    else:
        raise Exception("Process still alive")


def check_response(host: str, port: int):
    assert requests.get(f"http://{host}:{port}").text == '"hello world"'


def check_response_time(host: str, port: int, tol: float = 1e-2):
    s = time.time()
    requests.get(f"http://{host}:{port}")
    e = time.time()
    assert e-s < tol


@pytest.fixture(scope="session")
def server():
    proc = run_server(HOST, PORT, WORKERS)
    try:
        yield
    finally:
        shutdown_server(proc)


def test_main(server):
    check_response(HOST, PORT)
    check_response_time(HOST, PORT)
    check_response(HOST, PORT)
    check_response_time(HOST, PORT)

执行结果

$ curl http://localhost:8765
curl: (7) Failed to connect to localhost port 8765: Connection refused
$ pytest test_main.py
================== test session starts ================== platform win32 -- Python 3.7.5, pytest-6.2.4, py-1.10.0, pluggy-0.13.1
rootdir: .\
collected 1 item

test_main.py .                                                                                                                                                                                                                         [100%]

================== 1 passed in 20.24s ==================
$ curl http://localhost:8765
curl: (7) Failed to connect to localhost port 8765: Connection refused

使用 pytest 测试时，如何使用 worker >= 2 干净地终止 Uvicorn + FastAPI 应用程序

How to terminate a Uvicorn + FastAPI application cleanly with workers >= 2 when testing with pytest

python

pytest

fastapi

uvicorn

环境

图书馆

示例代码

执行结果

解决方案

执行结果