Alternative Caddy YAML config adapter with extra features.

Install with xcaddy.

xcaddy build \
    --with github.com/abiosoft/caddy-yaml

Specify with the --adapter flag for caddy run.

caddy run --config /path/to/yaml/config.yaml --adapter yaml

This project does a few extra things.

• Conditional configurations with Templates.

  #{if ne $ENVIRONMENT "production"}
  logging:
    logs:
      default: { level: DEBUG }
  #{end}

• Extension Fields. A convension used in Docker Compose.

  Top level keys prefixed with x- are discarded. This makes it easier to leverage YAML anchors and aliases, while avoiding Caddy errors due to unknown fields.

  # anchor declaration
  x-file_server: &file_server
    handler: file_server
    hide: [".git"]
    index_names: [index.html]
  # reuse alias
  ...
  handle:
    - <<: *file_server
      root: /var/www/blog/public
  # reuse alias
  ...
  handle:
    - <<: *file_server
      root: /var/www/api/docs

• Config-time environment variables

  Without the Caddyfile, Caddy's native configuration limits to runtime environment variables. There are use cases for knowing the environment variables at configuration time. e.g. troubleshooting purposes.

  listen: "#{ $PORT }"

If the above features are not needed or utilised, the behaviour is identical to iamd3vil/caddy_yaml_adapter.

Note that both adapters cannot be built with Caddy, they are incompatible. They both register as yaml config adapter and at most one config adapter is allowed per config format.

Anything supported by Go templates can be used, as well as any Sprig function.

Delimeters are #{ and }. e.g. #{ .title }. The choice of delimeters ensures the YAML config file remains a valid YAML file that can be validated by the schema.

Extension fields can be reused anywhere else in the YAML config.

x-hello: Hello from YAML template
x-nest:
  value: nesting

Referencing them without x- prefix.

...
handle:
  - handler: static_response
    body: "#{ .hello } with #{ .nest.value }"

If string interpolation is not needed, YAML anchors and aliases can also be used to achieve this.

Environment variables can be used in a template by prefixing with $.

listen:
  - "#{ $PORT }"
...
handler: file_server
root: "#{ $APP_ROOT_DIR }/public"

Caddy supports runtime environment variables via {env.*} placeholders.

Check the test YAML configuration file.

Apache 2