More complex inheritance in YAML?

Question

YAML has inheritance. The most clear example I have ever seen is here: http://blog.101ideas.cz/posts/dry-your-yaml-files.html

I need something more complex: I need to ov

Answer 1

For this sort of problems, I have created a tool: jq-front. By using yq + jq-front, you can achieve it by slightly modifying your input.

in.yaml:

$local: 
  database_default:
    server:
      ip: 192.168.1.5
      port: 2000
    db_name: test
    user: 
      name: root
      password: root

# database foo differs from default by only its port and user password
foo_database:
  $extends: [ database_default ]
  server:
    port: 2001
  db_name: foo
  user:
    password: foo_root

And you can process this file by a following command line.

$ yq . -j in.yaml | jq-front  | yq . -y

And you will get following output that you wanted.

foo_database:
  server:
    ip: 192.168.1.5
    port: 2001
  db_name: foo
  user:
    name: root
    password: foo_root

NOTE: jq-front is very slow. On my machine the command took 2.5s, which did not matter to me too much since system configuration can be read once and only the converted file is used by the rest of my program.

NOTE: If you use docker + bash, it's lot easier to install jq-front by docker. You only need to add following function to your .bashrc or a file that is sourced by it.

function jq-front() {
  docker run --rm -i \
    -v /:/var/lib/jf \
    -e JF_PATH_BASE="/var/lib/jf" \
    -e JF_PATH="${JF_PATH}" \
    -e JF_DEBUG=${JF_DEBUG:-disabled} \
    -e JF_CWD="$(pwd)" \
    dakusui/jq-front:"${JF_DOCKER_TAG:-latest}" "${@}"
}