FastAPI服务按Ctrl+C无法正常退出，求助解决方法

按下Ctrl+C后进程挂起，无法返回终端。以下是相关配置、运行脚本及日志：

pyproject.toml配置 #

[tool.pyright]
exclude = ["app/worker"]
ignore = ["app/worker"]

[tool.poetry]
name = "api"
version = "0.1.0"
description = ""
authors = ["SamiAlsubhi <sami@alsubhi.me>"]

[tool.poetry.dependencies]
python = ">=3.8,<3.9"
fastapi = "^0.65.2"
tortoise-orm = "^0.17.4"
asyncpg = "^0.23.0"
aerich = "^0.5.3"
networkx = "^2.5.1"
numpy = "^1.21.0"
ldap3 = "^2.9.1"
fastapi-jwt-auth = "^0.5.0"
python-multipart = "^0.0.5"
torch = "1.7.1"
pyts = "0.11.0"
Pint = "^0.17"
Cython = "^0.29.24"
python-dotenv = "^0.19.0"
arq = "^0.22"
uvicorn = {extras = ["standard"], version = "^0.15.0"}


[tool.poetry.dev-dependencies]
pytest = "^6.2.4"
requests = "^2.25.1"
asynctest = "^0.13.0"
coverage = "^5.5"
pytest-html = "^3.1.1"
pytest-sugar = "^0.9.4"
pytest-json-report = "^1.4.0"
pytest-cov = "^2.12.1"
pylint = "^2.11.1"
autopep8 = "^1.5.7"
black = "^22.3.0"
aiosqlite = "^0.17.0"

[build-system]
requires = ["poetry-core>=1.0.0"]
build-backend = "poetry.core.masonry.api"

运行脚本run.py #

"""本地开发环境运行API"""
import os
import uvicorn
from dotenv import load_dotenv

# 加载环境变量
load_dotenv("../.env")

if __name__ == "__main__":
    port = os.getenv("FASTAPI_PORT")
    port = int(port) if port else None
    uvicorn.run("app.main:app", host=os.getenv("FASTAPI_HOST"),
                port=port, reload=True)

运行及退出日志 #

(trendr) sami@Samis-MBP backend % python run.py
INFO:     即将监听以下目录的变化: ['/Users/name/Desktop/etc']
INFO:     Uvicorn运行在 http://0.0.0.0:1000 (按CTRL+C退出)
INFO:     使用watchgod启动重载进程 [70087]
INFO:     启动服务器进程 [70089]
INFO:     等待应用启动。
INFO:     应用启动完成。
^CINFO:     正在关闭
INFO:     服务器进程 [70089] 已结束
INFO:     ASGI 'lifespan' 协议似乎不被支持。

解决方案 #

• 禁用自动重载
  启动命令中移除reload=True，改为：

  uvicorn.run("app.main:app", host=os.getenv("FASTAPI_HOST"), port=port)
  

  自动重载模式下，watchgod可能导致父进程无法正确捕获终止信号，禁用后通常可正常退出。

• 手动终止进程
  若禁用重载仍无效，可通过进程ID强制终止：

  1. 执行ps aux | grep python查找父进程ID（即日志中的[70087]）
  2. 执行kill -9 <进程ID>强制终止

• 检查应用资源清理逻辑
  确认app.main中是否存在未正确关闭的异步资源（如数据库连接、后台任务），这些资源会阻塞进程退出。可通过FastAPI的shutdown事件显式清理：

  from fastapi import FastAPI
  
  app = FastAPI()
  
  @app.on_event("shutdown")
  async def shutdown_resources():
      # 此处添加资源关闭代码，例如数据库连接关闭
      await your_db_close_method()
  

• 升级uvicorn版本
  当前使用的uvicorn 0.15.0存在信号处理的已知问题，升级到0.20+版本可修复此类问题：

  poetry add uvicorn@latest --extras standard
  

内容的提问来源于stack exchange，提问作者Sami Al-Subhi