Initiate a virtualENV and install the following python packages using pip

$ python3 -m venv .venv
$ pip install requests
$ pip install flask
$ pip install flask_cors
$ pip install multidict
$ pip install flask_sqlalchemy
$ pip install flask_marshmallow
$ pip install marshmallow_sqlalchemy

Generate SQLite database

Enter into python interactive shell

$ python

>>> from mail import db
>>> db.create_all()
>>> exit()

Create ENV variables

MAILGUN_API_KEY -> mailgun private key
MAILGUN_MAIL_DOMAIN -> email domain for the temporary emails
MAILGUN_DROP_ROUTE -> id of the dropping route
MAILGUN_FWD_ROUTE -> id of the forwarding route

Start the app in ubuntu server

$ export LC_ALL=C.UTF-8
$ export LANG=C.UTF-8
$ export FLASK_APP=mail.py
$ flask run --host=0.0.0.0

setup gunicorn

• activate the python venv

$ pip install gunicorn
$ gunicorn -w 3 mail:app

setup supervisor

$ sudo apt install supervisor
$ sudo nano /etc/supervisor/conf.d/tempmail.conf

[program:tempmail]
directory=/home/<username>/<src_directory>
command=/home/<username>/<src_directory>/venv/bin/gunicorn -w 3 -b :5000 mail:app
user=<username>
autostart=true
autorestart=true
stopasgroup=true
killasgroup=true
stderr_logfile=/var/log/<app_name>/tempmail.err.log
stdout_logfile=/var/log/<app_name>/tempmail.out.log

create the supervisor log and output directory and files

$ sudo mkdir -p /var/log/<app_name>
$ sudo touch /var/log/<app_name>/tempmail.err.log
$ sudo touch /var/log/<app_name>/tempmail.out.log

$ sudo service supervisor restart