WSGI with nginx

Learn how to deploy Python web applications using the WSGI protocol and nginx, a popular open-source web server. …

Updated September 20, 2024

Learn how to deploy Python web applications using the WSGI protocol and nginx, a popular open-source web server.

WSGI (Web Server Gateway Interface) is a standard interface between web servers and Python web applications. It allows developers to write portable and reusable code that can be deployed on various web servers. In this article, we will explore how to deploy Python web applications using WSGI and nginx.

What is WSGI?

WSGI is a protocol that defines how a web server communicates with a Python web application. It provides a standard interface for the web server to pass requests to the application and receive responses back. This allows developers to focus on writing their application code without worrying about the underlying web server implementation.

Why Use WSGI?

WSGI offers several benefits, including:

Portability: WSGI applications can be deployed on any WSGI-compliant web server, making it easy to switch between different servers.
Flexibility: WSGI allows developers to write reusable code that can be easily integrated with other frameworks and libraries.
Scalability: WSGI enables efficient communication between the web server and application, making it easier to scale large applications.

How Does WSGI Work?

The WSGI protocol defines two main components:

Server: The web server, such as nginx, that receives incoming requests and passes them to the application.
Application: The Python web application that processes requests and returns responses to the server.

Here’s a high-level overview of the WSGI workflow:

A client sends an HTTP request to the web server (nginx).
The web server receives the request and creates a new WSGI environment, which contains information about the request.
The web server passes the WSGI environment to the application using the wsgi module.
The application processes the request and returns a response to the web server.
The web server receives the response from the application and sends it back to the client.

Deploying a Python Web Application with nginx and WSGI

To deploy a Python web application using WSGI and nginx, follow these steps:

Step 1: Install Required Packages

Install the nginx package on your system. On Ubuntu/Debian-based systems:

sudo apt-get install nginx

Install the wsgi module for Python:

pip install wsgiref

Step 2: Create a WSGI Application

Create a new file called app.py with the following code:

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

This is a simple WSGI application that returns an HTTP response with the text “Hello, World!”.

Step 3: Configure nginx

Create a new file called nginx.conf with the following code:

http {
    server {
        listen 80;
        location / {
            wsgi_pass localhost:8080;
            include uwsgi_params;
        }
    }
}

This configuration tells nginx to listen on port 80 and pass incoming requests to the WSGI application running on localhost:8080.

Step 4: Run the WSGI Application

Run the WSGI application using the following command:

wsgiref.simple_server.make_server('localhost', 8080, application).serve_forever()

This will start a new process that listens for incoming requests on port 8080.

Step 5: Test the Application

Open a web browser and navigate to http://localhost. You should see the text “Hello, World!” displayed in your browser.

Conclusion

In this article, we covered the basics of WSGI and how to deploy Python web applications using nginx. By following these steps, you can easily deploy your own WSGI-compliant application on a production server. Remember to always test your application thoroughly before deploying it to a live environment.

Key Takeaways