load balanced http proxies with custom headers

a.md

How to run?

git clone https://gist.github.com/b6cca73ed8dcf3388bbab12ad19cca54.git
cd b6cca73ed8dcf3388bbab12ad19cca54
docker-compose pull
docker-compose down -v
docker-compose up -d

How to test?

docker-compose.yml

version: "3"
services:
  load_balancer:
    image: nginx
    volumes:
      - ./load-balancer.conf:/etc/nginx/nginx.conf
    ports:
      - 80:80
    depends_on:
      - service_layer_proxy_user_1
      - service_layer_proxy_user_2
      - service_layer_proxy_user_3
  service_layer_proxy_user_1:
    image: nginx
    volumes:
      - ./proxy-user-1.conf:/etc/nginx/nginx.conf
    depends_on:
      - service_layer_lb
  service_layer_proxy_user_2:
    image: nginx
    volumes:
      - ./proxy-user-2.conf:/etc/nginx/nginx.conf
    depends_on:
      - service_layer_lb
  service_layer_proxy_user_3:
    image: nginx
    volumes:
      - ./proxy-user-3.conf:/etc/nginx/nginx.conf
    depends_on:
      - service_layer_lb
  service_layer_lb:
    image: containous/whoami

layout.png

load-balancer.conf

user  nginx;
worker_processes  1;

error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;

    keepalive_timeout  65;

    upstream backend {
        server service_layer_proxy_user_1;
        server service_layer_proxy_user_2;
        server service_layer_proxy_user_3;
    }

    server {
        listen       80;
        listen  [::]:80;
        server_name  localhost;

        location / {
            proxy_pass http://backend;
        }
    }
}

proxy-user-1.conf

user  nginx;
worker_processes  1;

error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;

    keepalive_timeout  65;

    server {
        listen       80;
        listen  [::]:80;
        server_name  localhost;

        location / {
            proxy_set_header service-layer-user-custom-header user-1;
            proxy_pass http://service_layer_lb;
        }
    }
}

proxy-user-2.conf

user  nginx;
worker_processes  1;

error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;

    keepalive_timeout  65;

    server {
        listen       80;
        listen  [::]:80;
        server_name  localhost;

        location / {
            proxy_set_header service-layer-user-custom-header user-2;
            proxy_pass http://service_layer_lb;
        }
    }
}

proxy-user-3.conf

user  nginx;
worker_processes  1;

error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;


events {
    worker_connections  1024;
}


http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile        on;

    keepalive_timeout  65;

    server {
        listen       80;
        listen  [::]:80;
        server_name  localhost;

        location / {
            proxy_set_header service-layer-user-custom-header user-3;
            proxy_pass http://service_layer_lb;
        }
    }
}

result.gif