caddy, docker, and dnsimple

16 Nov 2024

“I’m experimenting wth Caddy as a replacement for Nginx.”

Right now, that’s an aspirational statement, and not entirely factual.

Because, I would need to get Caddy to run properly to actually experiment with it.

Alright, haha – enough sarcasm.

In order for me to get Caddy to run with the following requirement - must have a Caddy docker image that supports DNSimple’s TLS challenge. The stock Caddy docker image you get from Dockerhub does not have all of the DNS providers. As a result, you need to build your own image containing the DNSimple module. How might you do this?

Edit your Dockerfile.

FROM caddy:builder AS builder

# Set Go environment variables to fetch dependencies directly
ENV GO111MODULE=on
ENV GOPROXY=https://goproxy.io
ENV GOSUMDB=off

RUN xcaddy build --with github.com/caddy-dns/dnsimple

FROM caddy:latest

COPY --from=builder /usr/bin/caddy /usr/bin/caddy

When I attempted to build an image with the above, not containing the ENV’s I would run into errors related to the proxies used to fetch the Go libraries. The ENV’s above were helpful to get things to work, thanks to the comments here in a Github issue.

Built with:

docker build -t caddy-with-dnsimple .

Bonus compose.yml contents:

services:
  caddy:
    image: caddy-with-dnsimple
    container_name: caddy
    hostname: caddy
    restart: always
    volumes:
      - ./data/caddy:/data
      - ./data/caddy/Caddyfile:/etc/caddy/Caddyfile
      - /etc/timezone:/etc/timezone:ro
      - /etc/localtime:/etc/localtime:ro
    ports:
      - 80:80
      - 443:443

And started with docker compose up -d