nginx.conf

# Set the number of worker processes to 4
worker_processes 4;

# Configure the maximum number of simultaneous connections for each worker process
events {
  worker_connections 1024;
}

# Configuration for the HTTP server
http {
  # Define an upstream server group named 'nodeapp'
  upstream nodeapp {
    server nodeapp:3000;  # Points to the Node.js app server at 'nodeapp:3000'
  }

  # Server block for handling HTTP requests
  server {
    listen 80;  # Listen on port 80 for incoming connections

    server_name localhost;  # Respond to requests with 'Host' header set to 'localhost'

    # Location block for handling requests to the root path '/'
    location / {
      # Reverse proxy configuration: forward requests to the 'nodeapp' upstream server
      proxy_pass http://nodeapp;
      
      # Proxy-related directives for proper communication with the upstream server
      proxy_http_version 1.1;
      proxy_set_header Upgrade $http_upgrade;
      proxy_set_header Connection 'upgrade';
      proxy_set_header Host $host;
      proxy_cache_bypass $http_upgrade;
    }
  }
}