Well, now you've really got me interested. Almost every case of a YAML eDSL would be better served by Starlark instead, in my Bazel-brained opinion.

I think Tilt Extensions highlights the combined power and composability that using Starlarks brings to Tilt: https://docs.tilt.dev/extensions.html.

Want to create a Kubernetes secret? It's as simple as:

    load('ext://secret', 'secret_yaml_generic')
    k8s_yaml(secret_yaml_generic(...))

Want to create that secret from Vault instead?

    load('ext://vault_client', 'vault_read_secret', 'vault_set_env_vars')
    vault_set_env_vars('https://localhost:8200','mytoken')
    my_foo = vault_read_secret('path/myfoo', 'value')
    my_bar = vault_read_secret('path/mybar', 'foobar')