Installing Apache with Python (mod_wsgi)

Installing Apache with Python (mod_wsgi) on Linux

In today's interconnected world, setting up a robust, scalable web server is a crucial skill for many developers and system administrators. Apache HTTP Server, paired with Python via mod_wsgi, is a potent combination for serving Python-based web applications to the internet. This tutorial will walk you through the steps to install Apache with the mod_wsgi module on a Linux system.

Step 1: Update Your System

Before beginning any installation, it’s good practice to update your system's package list. In Debian-based distributions like Ubuntu, use:

sudo apt update && sudo apt upgrade

For Red Hat-based distributions like CentOS, use:

sudo yum update

For openSUSE or SUSE Linux Enterprise, update your system with:

sudo zypper update

Keeping your system updated ensures compatibility and security.

Step 2: Install Apache

Apache is one of the most popular web servers in the world. To install Apache, execute one of the following commands based on your Linux distribution.

On Ubuntu/Debian:

sudo apt install apache2

On CentOS/Red Hat:

sudo yum install httpd

On openSUSE or SUSE Linux Enterprise:

sudo zypper install apache2

Once the installation is complete, you can start the Apache service with:

sudo systemctl start apache2       # Ubuntu/Debian
sudo systemctl start httpd         # CentOS/Red Hat
sudo systemctl start apache2       # openSUSE/SLE

Ensure it is enabled to start on boot:

sudo systemctl enable apache2      # Ubuntu/Debian
sudo systemctl enable httpd        # CentOS/Red Hat
sudo systemctl enable apache2      # openSUSE/SLE

Step 3: Install Python and mod_wsgi

You must have Python installed on your system. You can install Python with:

sudo apt install python3           # Ubuntu/Debian
sudo yum install python3           # CentOS/Red Hat
sudo zypper install python3        # openSUSE/SLE

Next, install mod_wsgi, which is an Apache module that provides a WSGI compliant interface for hosting Python-based web applications under Apache.

For Ubuntu/Debian:

sudo apt install libapache2-mod-wsgi-py3

For CentOS/Red Hat:

sudo yum install mod_wsgi

For openSUSE/SLE:

sudo zypper install apache2-mod_wsgi

If you're using Python 3, make sure to install the module specific to Python 3, as some systems might still default to Python 2.

Step 4: Configure Apache to Use mod_wsgi

Create a configuration file for your application in /etc/apache2/sites-available/ (Ubuntu/Debian) or /etc/httpd/conf.d/ (CentOS/Red Hat) or /etc/apache2/vhosts.d/ (openSUSE/SLE).

Here's an example configuration:

<VirtualHost *:80>
    ServerName yourdomain.com
    WSGIScriptAlias / /path/to/your/application.wsgi

    <Directory /path/to/your/application>
        Require all granted
    </Directory>
</VirtualHost>

Replace /path/to/your/application.wsgi with the path to your WSGI file, and update the ServerName with your domain.

Enable the new site configuration:

sudo a2ensite yourdomain.conf    # Ubuntu/Debian
sudo a2enconf yourdomain.conf    # openSUSE/SLE

Reload Apache to apply the changes:

sudo systemctl reload apache2     # Ubuntu/Debian
sudo systemctl reload httpd       # CentOS/Red Hat
sudo systemctl reload apache2     # openSUSE/SLE

Step 5: Testing Your Setup

Create a simple WSGI application to test your setup. Here’s a basic example you can use:

Create a file named application.wsgi:

def application(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/plain')])
    message = 'Hello, World!'
    return [message.encode('utf-8')]

Point to this file in your Apache configuration as illustrated earlier, then access your server’s IP or domain name from a browser.

Conclusion

Setting up Apache with mod_wsgi provides a scalable and efficient way to host Python applications. By following the steps above, you can create a robust environment for running your Python web applications, taking full advantage of Apache's proven stability and mod_wsgi's seamless Python integration. Ensure to test your setup thoroughly and consult your system's specific documentation for tweaks and optimizations particular to your environment. Happy hosting!