Auto Restart flask application on production crash.

we can achive this in multiple ways such as running application as service, or executing script based on exit codes of process or using libraries like pm2.

One way to automatically restart a Flask application after a crash in production is to use a process manager, such as supervisor, systemd or upstart.

To use these process managers with Flask, you’ll need to create a script to run your Flask application, and then configure the process manager to run the script. Here’s a simple example using Supervisor:

1. Create a script, for example run_flask_app.sh, to run your Flask application:

#!/bin/bash
export FLASK_APP=your_flask_app.py
export FLASK_ENV=production
flask run --host=0.0.0.0

1. Install and configure Supervisor:

sudo apt-get install supervisor
sudo vim /etc/supervisor/conf.d/flask_app.conf

1. Add the following content to the flask_app.conf file:

[program:flask_app]
command = /bin/bash /path/to/run_flask_app.sh
autostart = true
autorestart = true
user = your_user
stderr_logfile = /path/to/flask_app.err.log
stdout_logfile = /path/to/flask_app.out.log

1. Start and enable the Supervisor service:

sudo service supervisor start
sudo service supervisor enable

1. Reload the Supervisor configuration:

sudo supervisorctl reload

With this setup, Supervisor will automatically restart the Flask application if it crashes or becomes unresponsive. You can also use the Supervisor web interface or the supervisorctl command-line tool to monitor and control the status of the Flask application.