Expand variables in file_info fields

[aleroza]

Is your feature request related to a problem? Please describe.

I'm unable to use NFPM in configurations like this when I externally set 'owner' and 'group' as environment variables beforehand. The same issue occurs with 'mode' and 'mtime', but in those cases, NFPM returns an error about incorrect types.

contents:
  - src: ./build/pkg_root
    dst: ${PACKAGE_PREFIX}
    type: tree
    file_info:
      owner: ${PACKAGE_USER}
      group: ${PACKAGE_GROUP}
      mode: ${PACKAGE_MODE}
      mtime: ${PACKAGE_MTIME}
    expand: true

Describe the solution you'd like

Expand environment variables in file_info fields

Describe alternatives you've considered

In my case, the only alternatives are to use a separate nfpm.yaml file or the same user for different packages. However, these approaches feel too complicated and not ideal.

Search

• I did search for other open and closed issues before opening this.

Code of Conduct

• I agree to follow this project's Code of Conduct

Additional context

NFPM v2.41.2

[caarlos0]

in that case, you can probably use something like envsubst or some other templating language to pre-process the file?

[aleroza]

Yes, I can use other tools to pre-process nfpm.yml, but almost all fields can expand environment variables except for file_info...

In my opinion (though I admit it may be amateurish), this seems like an extremely simple feature to implement — it would just require adding a couple (or just two) of lines to one function:
https://github.com/goreleaser/nfpm/blob/main/nfpm.go#L193

I understand that you are not here to solve problems specific to my CI setup, but using a separate templating feels like unnecessary overhead for what appears to be a easy feature.