Path-Based Routing in Nginx

Introduction

Path-based routing allows directing requests to different backends based on the URL path. This is commonly used in microservices, reverse proxy setups, and load balancing.

Prerequisites

Installed Nginx
Basic understanding of Nginx configuration
Access to Nginx configuration files (e.g., /etc/nginx/nginx.conf or /etc/nginx/sites-available/default)

Configuration

Below is an example Nginx configuration for path-based routing:

server {
    listen 80;
    server_name example.com;
 
    location /app1/ {
        proxy_pass http://backend_app1;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
 
    location /app2/ {
        proxy_pass http://backend_app2;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
 
    location /php-app/ {
        root /var/www/php-app;
        index index.php;
        location ~ \.php$ {
            include fastcgi_params;
            fastcgi_pass unix:/run/php/php-fpm.sock;
            fastcgi_index index.php;
            fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
        }
    }
 
    location /react-app/ {
        root /var/www/react-app;
        index index.html;
        try_files $uri /index.html;
    }
 
    location /java-app/ {
        proxy_pass http://backend_java_app;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
 
    location /nodejs-app/ {
        proxy_pass http://backend_nodejs_app;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
    }
}

Explanation:

Requests to example.com/app1/ will be forwarded to http://backend_app1.
Requests to example.com/app2/ will be forwarded to http://backend_app2.
Requests to example.com/php-app/ will serve a PHP application using FastCGI and PHP-FPM.
Requests to example.com/react-app/ will serve a React application, ensuring the front-end routing works correctly.
Requests to example.com/java-app/ will be forwarded to a Java-based backend service.
Requests to example.com/nodejs-app/ will be forwarded to a Node.js backend service.
proxy_set_header ensures proper headers are forwarded to the backend.

Defining Backend Services

Define backend servers in the http block:

http {
    upstream backend_app1 {
        server 192.168.1.10:8080;
    }
 
    upstream backend_app2 {
        server 192.168.1.11:8080;
    }
 
    upstream backend_java_app {
        server 192.168.1.12:8080;
    }
 
    upstream backend_nodejs_app {
        server 192.168.1.13:3000;
    }
}

Testing the Configuration

After making changes, test the configuration:

nginx -t

If there are no errors, reload Nginx:

systemctl reload nginx

Conclusion

Path-based routing in Nginx enables efficient request forwarding based on URL paths. This method is essential for microservices, API gateways, and reverse proxy setups.

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