使用 Caddy 和 CloudFlare 在内网自动签发 https 证书

前置条件

Caddy 和 dns-cloudflare 插件，需要构建自己的 Docker 镜像
域名的 NS 服务器设置为 CloudFlare，配置好，大概一天后生效（保守估计）
内网 DNS 服务器，如果路由器支持定义局域网域名，可以不安装，我用的是 adguard
内网 Ubuntu 服务器
Ubuntu 安装 Docker

构建 Docker 镜像

在 Docker compose 同一层文件夹里，创建一个 Dockerfile。

FROM caddy:builder AS builder

RUN caddy-builder github.com/caddy-dns/cloudflare

FROM caddy:latest

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

在 Docker compose 使用 Dockerfile

version: "3.7"

services:
  caddy:
    container_name: caddy
    build:
      context: .
      dockerfile: Dockerfile

获取用户 API 令牌

登录到 CloudFlare Dashboard。
前往 “My Profile” > “API Tokens”。
确认你的 API 令牌具有所需的权限（Zone.Zone:Read 和 Zone.DNS:Edit），并且选择要使用的域名。
在 docker-compose.yml 同一层文件夹里创建一个 .env 文件

CLOUDFLARE_API_TOKEN = your token

然后修改文件权限，只允许本用户读写。

chmod 600 .env

编写 Caddyfile 文件

在 docker-compose.yml 同一层文件夹里，创建一个 Caddyfile 文件

caddy.luojiyin.top {
  tls {
       dns cloudflare {env.CLOUDFLARE_API_TOKEN}
  }
  respond / "Hello, world! This is a static response from Caddy." 200
}

Caddy 直接输出一个静态页面，验证签发是否成功。

完整的 Docker compose 文件

version: "3.7"

networks:
  caddy:
    name: caddy

services:
  caddy:
    container_name: caddy
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "80:80" # Remember that Caddy does HTTP to HTTPS redirections automatically.
      - "443:443"
    environment:
      - CADDY_INGRESS_NETWORK=caddy
      # If you don't want to write your token here, remember that Docker Compose picks up
      # variables from an .env file if present in the same directory as the compose file.
      - CLOUDFLARE_API_TOKEN=${CLOUDFLARE_API_TOKEN}
    networks:
      - caddy
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock"
      # It is important to have these to conserve data after the container restarts
      - "./data:/data"
      # Unless we want to SSH to our server every time it restarts.
      - "./config:/config"
      - "./Caddyfile:/etc/caddy/Caddyfile"
    restart: unless-stopped

完整的文件夹目录

├── Caddyfile
├── config
│   └── caddy  [error opening dir]
├── data
│   └── caddy  [error opening dir]
├── docker-compose.yml
└── Dockerfile

启动服务

docker compose up

没加 -d , 第一次启动查看日志，会读取 Dockerfile 文件构建镜像，加入 CloudFlare 插件，从 .env 文件获取 CLOUDFLARE_API_TOKEN 。

caddy  | {"level":"info","ts":1715595177.3236513,"logger":"tls.obtain","msg":"obtaining certificate","identifier":"caddy.luojiyin.top"}
caddy  | {"level":"info","ts":1715595177.32397,"logger":"tls","msg":"finished cleaning storage units"}
caddy  | {"level":"info","ts":1715595179.2300568,"logger":"tls.issuance.acme","msg":"waiting on internal rate limiter","identifiers":["caddy.luojiyin.top"],"ca":"https://acme-v02.api.letsencrypt.org/directory","account":""}
caddy  | {"level":"info","ts":1715595179.2301404,"logger":"tls.issuance.acme","msg":"done waiting on internal rate limiter","identifiers":["caddy.luojiyin.top"],"ca":"https://acme-v02.api.letsencrypt.org/directory","account":""}
caddy  | {"level":"info","ts":1715595180.2085311,"logger":"tls.issuance.acme.acme_client","msg":"trying to solve challenge","identifier":"caddy.luojiyin.top","challenge_type":"dns-01","ca":"https://acme-v02.api.letsencrypt.org/directory"}
caddy  | {"level":"info","ts":1715595197.6058002,"logger":"tls.issuance.acme.acme_client","msg":"authorization finalized","identifier":"caddy.luojiyin.top","authz_status":"valid"}
caddy  | {"level":"info","ts":1715595197.605848,"logger":"tls.issuance.acme.acme_client","msg":"validations succeeded; finalizing order","order":"https://acme-v02.api.letsencrypt.org/acme/order/1723709497/269014373307"}
caddy  | {"level":"info","ts":1715595199.1746569,"logger":"tls.issuance.acme.acme_client","msg":"successfully downloaded available certificate chains","count":2,"first_url":"https://acme-v02.api.letsencrypt.org/acme/cert/049f29c5f90a9c14bd9acdb84ff4ab90af77"}
caddy  | {"level":"info","ts":1715595199.176429,"logger":"tls.obtain","msg":"certificate obtained successfully","identifier":"caddy.luojiyin.top"}
caddy  | {"level":"info","ts":1715595199.1766984,"logger":"tls.obtain","msg":"releasing lock","identifier":"caddy.luojiyin.top"}

没有报错信息，基本成功了。