How to make alive nohup process? - python-3.x

Question

I am using the nohup command with Python and Flask for background process. After I close the terminal it is working fine but after 1 or 2 days the process stops. Can someone tell me how to keep the background process running? I am using below command:
screen
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nohup python -m flask run --cert local.crt --key local.key --host=0.0.0.0 --port=443 &
ctrl+a+d

Answer 1

Let's assume all your Flask code resides in the folder /home/abc_user/flask_app.
Steps
Create a file flask-server.service in /etc/systemd/system.
[Unit]
Description=Flask server
After=network.target
[Service]
User=abc_user
Group=abc_user
WorkingDirectory=/home/abc_user/flask_app
ExecStart=python -m flask run --cert local.crt --key local.key --host=0.0.0.0 --port=443
Restart=always
[Install]
WantedBy=multi-user.target
Run sudo systemctl daemon-reload.
Start the service using systemctl start flask-server.service.
Check that it has started by systemctl status flask-server.service. Status should say "running".
If you want your flask server to auto-start after reboots, run systemctl enable flask-server.service
Some common operations
Check current status - systemctl status flask-server.service
Start the service - systemctl start flask-server.service
Stop the service - systemctl stop flask-server.service
Check logs - journalctl -u flask-server.service
Stream logs - journalctl -f -u flask-server.service
Check logs in past 1 hour - journalctl -u flask-server.service --since "1 hour ago"

Answer 2

Try nohup python -m flask run --cert local.crt --key local.key --host=0.0.0.0 --port=443 >/dev/null 2>&1&
Use nohup , you should redirct you print to /dev/null or log, Otherwise it will be create a file nohup.out occupy disk space.
Most times we use gunicorn and supervisor to manager flask application.

Answer 3

Did you maybe shut down the computer the flask server is running on ?
If so, the problem will be solved by either not shutting down your computer or starting the flask server again after shutting down !

Answer 4

nohup is a POSIX command to ignore the HUP (hangup) signal. The HUP signal is, by convention, the way a terminal warns dependent processes of logout.
Output that would normally go to the terminal goes to a file called nohup.out if it has not already been redirected.
See nohup.out for searching errors in ./ or executed directory. It is no nohup error. Look nohup.out and google error and will refresh question.