Flask调试模式关闭应用时触发WinError 10038错误求助

问题描述 #

Flask应用与MongoDB运行正常，但开启调试模式（debug=1）后，关闭应用时出现如下错误：

代码示例 #

import datetime
from flask import Flask, render_template, request
from pymongo import MongoClient

app = Flask(__name__)
client = MongoClient(<connectionlink>)
app.db = client.blog


@app.route("/", methods=["GET", "POST"])
def index():
    if request.method == "POST":
        entry_content = request.form.get("content")
        formatted_date = datetime.datetime.today().strftime("%d-%m-%Y")
        app.db.entries.insert_one({"content":entry_content, "date":formatted_date})
        
    entries_with_date = [
        (
            entry["content"],
            entry["date"],
            datetime.datetime.strptime(entry["date"], "%d-%m-%Y").strftime("%b %d")
        )
        for entry in app.db.entries.find({})
    ]
    return render_template("index.html", entries=entries_with_date)

错误信息 #

Exception in thread Thread-1 (serve_forever):
Traceback (most recent call last):
File "C:\Users\user\.pyenv\pyenv-win\versions\3.11.1\Lib\threading.py", line 1038, in _bootstrap_inner
self.run()
File "C:\Users\user\.pyenv\pyenv-win\versions\3.11.1\Lib\threading.py", line 975, in run
self._target(*self._args, **self._kwargs)
File "C:\Users\user\Desktop\flask\.venv\Lib\site-packages\werkzeug\serving.py", line 766, in serve_forever
super().serve_forever(poll_interval=poll_interval)
File "C:\Users\user\.pyenv\pyenv-win\versions\3.11.1\Lib\socketserver.py", line 233, in serve_forever
ready = selector.select(poll_interval)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\user\.pyenv\pyenv-win\versions\3.11.1\Lib\selectors.py", line 323, in select
r, w, _ = self._select(self._readers, self._writers, [], timeout)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\user\.pyenv\pyenv-win\versions\3.11.1\Lib\selectors.py", line 314, in _select
r, w, x = select.select(r, w, w, timeout)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
OSError: [WinError 10038] an operation was attempted on something that is not a socket.

解决方法 #

1. 关闭调试模式的重载器 #

调试模式默认启动代码重载器（多线程），这是Windows下socket清理异常的核心原因，可通过两种方式禁用：

• 命令行启动：

  flask run --debug --no-reload
  

• 代码中设置：
  添加启动逻辑并关闭重载器：

  if __name__ == "__main__":
      app.run(debug=True, use_reloader=False)
  

2. 优雅关闭MongoDB连接 #

添加应用退出时的清理逻辑，确保MongoClient连接被正确释放：

import atexit
from flask import Flask, render_template, request
from pymongo import MongoClient
import datetime

app = Flask(__name__)
client = MongoClient(<connectionlink>)
app.db = client.blog

# 注册退出信号，关闭Mongo连接
atexit.register(client.close)

@app.route("/", methods=["GET", "POST"])
def index():
    # 原函数逻辑不变
    if request.method == "POST":
        entry_content = request.form.get("content")
        formatted_date = datetime.datetime.today().strftime("%d-%m-%Y")
        app.db.entries.insert_one({"content":entry_content, "date":formatted_date})
        
    entries_with_date = [
        (
            entry["content"],
            entry["date"],
            datetime.datetime.strptime(entry["date"], "%d-%m-%Y").strftime("%b %d")
        )
        for entry in app.db.entries.find({})
    ]
    return render_template("index.html", entries=entries_with_date)

if __name__ == "__main__":
    app.run(debug=True)

3. 更新依赖包 #

Windows下的socket处理bug可能已在新版本中修复，执行以下命令更新相关依赖：

pip install --upgrade werkzeug pymongo

内容的提问来源于stack exchange，提问作者Bora Bircan