How to configure Flask with WSGI ?

# Configure Flask with WSGI

1.Install and Enable mod_wsgi

sudo apt-get install libapache2-mod-wsgi python-dev

#To enable mod_wsgi, run the following command: 

sudo a2enmod wsgi  

2. Creating a Flask App

a. cd /var/www 

b. sudo mkdir FlaskApp

c. cd FlaskApp

d. sudo mkdir FlaskApp

e .cd FlaskApp
f .sudo mkdir static templates    

3.Now, create the __init__.py file that will contain the flask application logic.

sudo nano __init__.py 

#Add following logic to the file:

from flask import Flask
app = Flask(__name__)
@app.route("/")
def hello():
    return "Hello, I love Digital Ocean!"
if __name__ == "__main__":
    app.run() 

4.Configure and Enable a New Virtual Host

sudo nano /etc/apache2/sites-available/FlaskApp (for older ubuntu version)

sudo nano /etc/apache2/sites-available/FlaskApp.conf (for 13+ ubuntu version) 

#Add the following lines of code to the file to configure the virtual host.

<VirtualHost *:8080>
  ServerName localhost
  ServerAdmin admin@mywebsite.com
  WSGIScriptAlias / /var/www/FlaskApp/flaskapp.wsgi
  <Directory /var/www/FlaskApp/FlaskApp/>
   Order allow,deny
   Allow from all
  </Directory>
  Alias /static /var/www/FlaskApp/FlaskApp/static
  <Directory /var/www/FlaskApp/FlaskApp/static/>
   Order allow,deny
   Allow from all
  </Directory>
  ErrorLog ${APACHE_LOG_DIR}/error.log
  LogLevel warn
  CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost> 

Note :- Define LISTEN port before VirtualHost

Save and close the file.

5.Enable the virtual host with the following command:

sudo a2ensite FlaskApp

 6.Create the .wsgi File

cd /var/www/FlaskApp
sudo nano flaskapp.wsgi 

Add the following lines of code to the flaskapp.wsgi file:

#!/usr/bin/python
import sys
import logging
logging.basicConfig(stream=sys.stderr)
sys.path.insert(0,"/var/www/FlaskApp/")

from FlaskApp import app as application
application.secret_key = '123456789' 

Save and close the file.

Now your directory structure should look like this:

|--------FlaskApp
|----------------FlaskApp
|-----------------------static
|-----------------------templates
|-----------------------__init__.py
|----------------flaskapp.wsgi

7.Than Restart the apache server following this command

sudo service apache2 restart