Caddy Reverse Proxy with Dynamic Mappings

This project provides a Dockerized Caddy reverse proxy that dynamically generates its configuration (Caddyfile) based on mappings defined in the MAPPING environment variable.

Features

• Dynamic Configuration: The Caddyfile is generated at runtime based on the MAPPING environment variable.
• Lightweight: Built on the official Caddy web server image.
• Simple to Use: Configure URL mappings using a single JSON variable.

Prerequisites

• Docker installed on your system.

Build the Docker Image

Run the following command to build the Docker image:

docker build -t caddy-reverse-proxy-env-var .

Run the Container

Start a container with your desired mappings:

docker run -d \
  --name caddy-reverse-proxy-env-var \
  -e MAPPING='[{"example.com":"backend1:8080"},{"api.example.com":"backend2:9090"}]' \
  -p 80:80 \
  caddy-reverse-proxy-env-var

Add http if you want to disable https redirect

docker run -d \
  --name caddy-reverse-proxy-env-var \
  -e MAPPING='[{"http://example.com":"backend1:8080"},{"http://api.example.com":"backend2:9090"}]' \
  -p 80:80 \
  caddy-reverse-proxy-env-var

MAPPING Format

The MAPPING environment variable should be a JSON array of objects, where each object maps a source URL to a target address. Example:

[
  {"example.com": "backend1:8080"},
  {"api.example.com": "backend2:9090"}
]

Debugging

To verify the configuration, check the container logs for the generated Caddyfile:

docker logs caddy-reverse-proxy-env-var

Stopping and Cleaning Up

Stop and remove the container when it is no longer needed:

docker stop caddy-reverse-proxy-env-var
docker rm caddy-reverse-proxy-env-var

Docker Hub Repository

You can pull the prebuilt image from Docker Hub:

https://hub.docker.com/repository/docker/lenny4/caddy-reverse-proxy-env-var/general

To use the image from Docker Hub:

docker pull lenny4/caddy-reverse-proxy-env-var

License

This project is licensed under the MIT License. Contributions are welcome!