Move build from positional args to named.

[supakeen]

It'd be nicer if the image-builder build subcommand takes named arguments instead of positional arguments. Currently it looks like this:

image-builder build --distro fedora-41 minimal-raw blueprint.toml

I propose:

image-builder build --distro fedora-41 --type minimal-raw --blueprint blueprint.toml

This would allow for multi-type builds (a very strong advantage of the osbuild system):

image-builder build --distro fedora-41 --type iso --type qcow2 --blueprint blueprint.toml

And would allow us to in the future have other inputs except the built-in image types such as a custom YAML file for custom images.

[mvo5]

Fwiw, I like that it's more "uniform" this way, i.e. to me it feels a bit unbalanced that we currently have "--distro centos-9" but type is just an positional argument and has no --type. But then its a bit more typing for our users.

We should probably have a brainstorm again in the new year.

[achilleas-k]

I agree, there's a convenience to positional args, but I think once you go beyond 3, it starts becoming easier to forget which is which. I think the extra typing is an acceptable tradeoff for explicitness. I wouldn't be against going that way.

[mvo5]

@ondrejbudai Any (strong) opinions here?

[ondrejbudai]

I only have one strong opinion: the user experience for the first time users must be as simple as possible. I like that positional arguments is all you need to get an image, I find it extremely user-friendly: image-builder build qcow2.

Requiring a named argument makes the command longer, and imo slightly harder to document.

---

Would it make sense to split these use-cases into 2 subcommands? One very simple one (build) for the masses, one complex one for people that need the complexity to succeed. I'm even thinking that the complex command shouldn't accept arguments, but rather a file (might be an overkill?):

$ cat fedora-iot.yaml
ostree-url: example.com/fedora
ostree-ref: fedora/rawhide
types:
  - iot-installer
  - iot-simplified-installer
  - iot-raw
  - iot-container
distro: fedora-rawhide
$ image-builder-cli multi-build fedora-iot.yaml

[supakeen]

I'm fine with either approach; I created a quick PR to have --type because it was very little work to have it.

I'll add an opinion that if we do what @ondrejbudai proposes to please call these commands build-multi (so the reverse) so they sort correctly (all under build :)).

Perhaps we can rename build to something else, e.g. build-koji so we can provide a (for now) approach I can implement while we think about what other cases exist?