How do I terminate a flask app that's running as a service?
Solution 1
I recommend you use http://supervisord.org/. Actually not work in Windows, but with Cygwin you can run supervisor as in Linux, including run as service.
For install Supervisord: https://stackoverflow.com/a/18032347/3380763
After install you must configure the app, here an example: http://flaviusim.com/blog/Deploying-Flask-with-nginx-uWSGI-and-Supervisor/ (Is not necessary that you use Nginx with the Supervisor's configuration is enough)
Solution 2
You can stop the Werkzeug web server gracefully before you stop the Win32 server. Example:
from flask import request
def shutdown_server():
func = request.environ.get('werkzeug.server.shutdown')
if func is None:
raise RuntimeError('Not running with the Werkzeug Server')
func()
@app.route('/shutdown', methods=['POST'])
def shutdown():
shutdown_server()
return 'Server shutting down...'
If you add this to your Flask server you can then request a graceful server shutdown by sending a POST
request to /shutdown
. You can use requests or urllib2 to do this. Depending on your situation you may need to protect this route against unauthorized access.
Once the server has stopped I think you will have to no problem stopping the Win32 service.
Note that the shutdown code above appears in this Flask snippet.
Solution 3
You could also trick Flask into believing you pressed Ctrl + C:
def shutdown_flask(self):
from win32api import GenerateConsoleCtrlEvent
CTRL_C_EVENT = 0
GenerateConsoleCtrlEvent(CTRL_C_EVENT, 0)
Then simply call shutdown_flask()
in your SvcStop()
:
try:
# try to exit gracefully
self.shutdown_flask()
except Exception as e:
# force quit
os._exit(0)
Should shutdown_flask()
fail for some reason, os._exit()
makes sure your service will end (albeit with a nasty warning), by halting the interpreter.
Chockomonkey
Updated on July 05, 2022Comments
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Chockomonkey almost 2 years
I was able to get my flask app running as a service thanks to Is it possible to run a Python script as a service in Windows? If possible, how?, but when it comes to stopping it i cannot. I have to terminate the process in task manager.
Here's my run.py which I turn into a service via run.py install:
from app import app from multiprocessing import Process import win32serviceutil import win32service import win32event import servicemanager import socket class AppServerSvc (win32serviceutil.ServiceFramework): _svc_name_ = "CCApp" _svc_display_name_ = "CC App" def __init__(self,args): win32serviceutil.ServiceFramework.__init__(self,args) self.hWaitStop = win32event.CreateEvent(None,0,0,None) socket.setdefaulttimeout(60) def SvcStop(self): self.ReportServiceStatus(win32service.SERVICE_STOP_PENDING) win32event.SetEvent(self.hWaitStop) server.terminate() server.join() def SvcDoRun(self): servicemanager.LogMsg(servicemanager.EVENTLOG_INFORMATION_TYPE, servicemanager.PYS_SERVICE_STARTED, (self._svc_name_,'')) self.main() def main(self): server = Process(app.run(host = '192.168.1.6')) server.start() if __name__ == '__main__': win32serviceutil.HandleCommandLine(AppServerSvc)
I got the process stuff from this post: http://librelist.com/browser/flask/2011/1/10/start-stop-flask/#a235e60dcaebaa1e134271e029f801fe but unfortunately it doesn't work either.
The log file in Event Viewer says that the global variable 'server' is not defined. However, i've made server a global variable and it still gives me the same error.