为什么 Flask 应用程序会创建两个进程? [英] Why does a Flask app create two process?

问题描述

据我所知，Flask 应该创建一个线程和第二个线程来运行它，但我看到的是总是有两个进程在运行，而不是线程.即使是最简单的应用.

As far as I understood Flask should create a thread and a second thread to run on it, but what I see is there are always two processes, not threads, running. Even for the simplest app.

from flask import Flask
from flask import render_template, request, flash, session, redirect

app = Flask(__name__)

@app.route('/')
def hello_world():
    return 'Hello World!'

app.run(host="192.168.21.73", port=5000, debug=True)

可以看到有两个进程在运行:

You can see two process running:

ps -x
5026 ttyO0    S+     0:01 /usr/bin/python ./test_flask.py
5031 ttyO0    Sl+    0:45 /usr/bin/python ./test_flask.py

这里发生了什么?

推荐答案

这是因为您正在使用重新加载器运行开发服务器.重新加载器监控文件系统的变化，并在不同的进程中启动真正的应用程序，所以总共有两个进程.

It's because you're running the dev server with the reloader. The reloader monitors the filesystem for changes and starts the real app in a different process, so there are two total processes.

您可以通过在调用 run 时设置 debug=False 或 use_reloader=False 来禁用重载器.

You can disable the reloader by settting debug=False or use_reloader=False when calling run.

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