问题
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)
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
What is happening here?
回答1:
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.
You can disable the reloader by settting debug=False or use_reloader=False when calling run.
来源：https://stackoverflow.com/questions/28585033/why-does-a-flask-app-create-two-process