cepharum/reverse-proxy repository overview

⁠cepharum/reverse-proxy

most simple reverse proxy for use in stacks

⁠Source Code & Issues

There is a public git repository⁠ for inspecting this image in detail.

⁠Usage

This image is applying minimal extension to official image of HA-Proxy⁠ to have a simple reverse proxy in HTTP mode with peer information controlled via environment variables. It is meant to be used in conjunction with other services for exposing their web interface in situations like this one:

• There is a docker swarm.
• An edge router like Traefik⁠ is used to expose some services of separate stacks to the public. All those services have to join network cloud-edge.

• You are going to have several database engines provided for shared use by stacks of your swarm, like ReThinkDB⁠.
  • You want to control access on either database engine by having all consuming services sharing distinct network with either database engine.
  • For every provided database engine in its distinct internal network, you want it to be accessible via some simple hostname such as db.
• This database engine comes included with a web-based administration GUI you want to access remotely, thus need to expose it to the public using edge router.

You might end up with a solution like this one:

version: "3.7"

services:
  db:
    image: rethinkdb
    networks:
      - db-rethink
      - cloud-edge

networks:
  cloud-edge:
    external: true

In this case a host named db is joining network cloud-edge used for exposing all services of swarm to the public. Thus, either service exposed that way is capable of reaching this particular database engine using hostname db. And you can't have different database engines exposed to different services joining different networks as hostname db, anymore.

You may fix this issue by using some prefix to imitate the namespace support currently missing in overlay networks of Docker swarm.

version: "3.7"

services:
  kdiehsncnxk-db:
    image: rethinkdb
    networks:
      - db-rethink
      - cloud-edge

networks:
  cloud-edge:
    external: true

By prepending a random string to the service name, it is possible to prevent hostname clashes in services bound to cloud-edge network. However, this prefix must be used with all services consuming this database engine. In addition, separating database engines is sort of weakened.

Now, this is when cepharum/reverse-proxy is getting useful:

version: "3.7"

services:
  db:
    image: rethinkdb
    networks:
      - db-rethink

  xdgehfirjdls-my-custom-proxy:
    image: cepharum/reverse-proxy
    networks:
      - db-rethink
      - cloud-edge
    environment:
      PEER_ADDRESS: db
      PEER_PORT: 8080

networks:
  db-rethink:
    external: true
  cloud-edge:
    external: true

This time, the database engine is keeping its simple hostname. Except for its web-based GUI, any service interested in accessing this database engine must join the engine's network explicitly.