我在计划构建的非常原始的Rest服务器中有一个后台线程。唯一的问题是该后台线程似乎运行了两次，最小的可重复代码在这里：
MoviesViewModel @Inject constructor(private val movieService: MovieService): ViewModel() import threading
import time
from flask import Flask
app = Flask(__name__, template_folder='templates')
def feedworker():
print("STARTING FEEDWORKER")
while True: # background thread. never stop updating
time.sleep(75)
def runbackground():
feeder_thread = threading.Thread(target=feedworker)
feeder_thread.daemon = True
feeder_thread.start()
if __name__ == "__main__":
runbackground()
app.run(debug=True)
应该启动挂起的后台runbackground。最大的问题是，它似乎两次启动了（终端输出）：
feedworker所有日志（还有更多日志）表明STARTING FEEDWORKER
* Serving Flask app "testthread" (lazy loading)
* Environment: production
WARNING: Do not use the development server in a production environment.
Use a production WSGI server instead.
* Debug mode: on
* Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
* Restarting with stat
STARTING FEEDWORKER
* Debugger is active!
* Debugger PIN: 297-719-925
已启动两次。但是如果您注释掉最后一行（feedworker）或仅注释app.run(debug=True)，它将仅运行一次。
为什么调试器会使其运行两次？