Migrating Caddy v1 to v2 using Caddyfile

April 3, 2021

I like using Caddy as a HTTPS server with automatic SSL certificates using Let’s Encrypt. With a few configuration lines you can get up and running in no time.

Recently I switched VPS providers and ended up having to migrate Caddy from v1 to v2. The documentation for Caddy is wonderful and chockful with emojis. The getting started tutorial starts by telling you how a Caddyfile looks like in v2, where my confusion started. As I mostly need reverse proxies, the very first example there looks like this:

localhost

reverse_proxy 127.0.0.1:9000

which quite frankly looks quite different than what it looked like in v1. No curly brackets. How do I define multiple domains? Well apparently, the above is the equivalent to

localhost {
  reverse_proxy 127.0.0.1:9000
}

which is sorta what you’re used to! They do mention this somewhere else but it is not mentioned in the v2 upgrade guide.

So to help you, here’s my v1 Caddyfile:

subdomain1.tricht.eu {
  proxy / localhost:7777
}
subdomain2.tricht.eu {
  proxy /notifications/hub/negotiate localhost:8081 {
    transparent
  }
  proxy /notifications/hub localhost:3012 {
    websocket
  }
  proxy / localhost:8081 {
    transparent
  }
}
subdomain3.tricht.eu {
  proxy / localhost:8080 {
    transparent
  }
  limits {
    header 64kb
    body 1gb
  }
  header / {
    Strict-Transport-Security "max-age=31536000; includeSubdomains; preload"
    X-XSS-Protection "1; mode=block;"
    X-Content-Type-Options "nosniff"
    X-Frame-Options "SAMEORIGIN"
  }
  gzip {
    ext *
    level 4
  }
}

and what it looks like in v2:

subdomain1.tricht.eu {
  reverse_proxy localhost:7777
}
subdomain2.tricht.eu {
  reverse_proxy /notifications/hub/negotiate localhost:8081
  reverse_proxy /notifications/hub localhost:3012
  reverse_proxy localhost:8081
}
subdomain3.tricht.eu {
  reverse_proxy localhost:8080
  header {
    Strict-Transport-Security "max-age=31536000; includeSubdomains; preload"
    X-XSS-Protection "1; mode=block;"
    X-Content-Type-Options "nosniff"
    X-Frame-Options "SAMEORIGIN"
  }
  encode gzip
}

So not much has changed, except a missing limits directive and confusing documentation.