npm run flask-server "ValueError: signal only works in main thread"

when I run npm run flask-server, I got this error

> FLASK_APP=$PWD/autoapp.py FLASK_DEBUG=1 flask run

 * Serving Flask-SocketIO app "autoapp"
 * Forcing debug mode on
 * Restarting with fsevents reloader
 * Debugger is active!
 * Debugger PIN: 228-328-364
Exception in thread Thread-1:
Traceback (most recent call last):
  File "/usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 801, in __bootstrap_inner
    self.run()
  File "/usr/local/Cellar/python/2.7.13/Frameworks/Python.framework/Versions/2.7/lib/python2.7/threading.py", line 754, in run
    self.__target(*self.__args, **self.__kwargs)
  File "/usr/local/lib/python2.7/site-packages/flask_socketio/cli.py", line 56, in run_server
    return run_command()
  File "/usr/local/lib/python2.7/site-packages/click/core.py", line 722, in __call__
    return self.main(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/click/core.py", line 697, in main
    rv = self.invoke(ctx)
  File "/usr/local/lib/python2.7/site-packages/click/core.py", line 895, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/usr/local/lib/python2.7/site-packages/click/core.py", line 535, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/click/decorators.py", line 64, in new_func
    return ctx.invoke(f, obj, *args[1:], **kwargs)
  File "/usr/local/lib/python2.7/site-packages/click/core.py", line 535, in invoke
    return callback(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/flask/cli.py", line 438, in run_command
    use_debugger=debugger, threaded=with_threads)
  File "/usr/local/lib/python2.7/site-packages/werkzeug/serving.py", line 737, in run_simple
    reloader_type)
  File "/usr/local/lib/python2.7/site-packages/werkzeug/_reloader.py", line 257, in run_with_reloader
    signal.signal(signal.SIGTERM, lambda *args: sys.exit(0))
ValueError: signal only works in main thread

I search on google and got this: https://stackoverflow.com/questions/31264826/start-a-flask-application-in-separate-thread

It seems I can’t use debug=True and use_reloader=True both. But it’s useful reloading server when code changes in debug mode. Then I change autoapp.py like this:

# -*- coding: utf-8 -*-
"""Create an application instance."""
from flask.helpers import get_debug_flag

from myflaskapp.app import create_app
from myflaskapp.settings import DevConfig, ProdConfig

CONFIG = DevConfig if get_debug_flag() else ProdConfig
app = create_app(CONFIG)
app.run(debug=True, use_reloader=True)

and just run python autoapp.py, It works well.

[coolbreezeqf]

 FLASK_APP=app.py FLASK_DEBUG=1 flask run
 * Serving Flask-SocketIO app "app"
...

卸载 Flask-SocketIO pip uninstall Flask-SocketIO 后，就能正常运行

 FLASK_APP=app.py FLASK_DEBUG=1 flask run
 * Serving Flask app "app"
...

[jamescurtin]

Going to close this issue out, as it seems the problem was identified & the template does not currently use Flask-SocketIO. Thank you!