Background

I am designing a CLI for a container build tool I am making. It uses Gentoo's Portage behind the scenes

Question

I want to give the user the ability to specify a custom package repository. The repository must have a name, URI and sync type.

custom_repo: {
    uri: 'https://...',
    name: 'custom',
    sync_type: 'git',
}

How do I have the user represent this in the CLI? keep in mind, this is not the main input and is optional.

One way is to make this only provide-able via a config file using JSON or another structured data representation. But I want to see if theres a good way to do it in the CLI

What I am thinking of: command --custom-repo uri='https://...',name=custom,sync_type=git --custom-repo ... [main input]

Is this the best way of doing this?