$text substitutions in catalog descriptor files do not support local files

Expected Behavior

According to the documentation for $text, $json and $yaml, we should be able to use $text: <local file path> to substitute catalog-info.yaml. This is especially useful for spec.definition in API entities.

Example

kind: API
...
spec:
  type: openapi
  definition:
    $text: ./api-definition.yaml

Actual Behavior

Catalog throws an error when processing API entities where $test is either a relative local path or an absolute local path. It works only with URLs.

2022-10-28T12:16:01.069Z catalog warn Processor PlaceholderProcessor threw an error while preprocessing; caused by Error:
Placeholder $text could not form a URL out of /Users/himanshumishra/workspace/backstage/packages/catalog-
model/examples/apis/petstore-api.yaml and ./my-api-definition.yaml, Error: URL parsing failed. type=plugin entity=api:default/petstore

Steps to Reproduce

Update an API definition where $text points to a local file path

Context

Looking into the processor code, there is a comment saying the support for relative file is not there.

Your Environment

• Browser Information:

• Output of yarn backstage-cli info:

master branch of this repository

[awanlin]

Sorry for sending you down the wrong path @OrkoHunter. I wonder why the person on Discord said it worked for them 🤔

[OrkoHunter]

@doemEINS Oh awesome! I wonder if that still works if the catalog-info.yaml is registered locally instead of from a URL? In my case, I have a local instance where my catalog-info.yaml is registered locally using catalog.locations in app-config.yaml.