lorax-composer uses the host's repositories for building images. This is
prone to accidental configuration errors and duplicates functionality
(adding custom repositories via the source API is much more explicit).
However, blueprints don't specify the distribution they're based on.
This is something they should do in the future to enable cross-distro
image builds. Until then, read `/etc/os-release` to detect the host OS
and use that as the base distro for a blueprint.
Detection works by concatenating the ID field with a `-` and the
VERSION_ID field. This mandates how additional distributions should
register themselves to the `distro` package.
If composer cannot build the detected distro, fall back to fedora-30.
Use this detection everywhere that fedora-30 was hard-coded before.
Introduce the `distro` package, which contains an interface for OS
implementations. Its main purpose is to convert a blueprint to a
distro-specific pipeline.
Also introduce the `distro/fedora30` package. It is the first
implementation of the distro interface. Most of its code has been copied
with minimal modifications from the blueprint package.
The `blueprint` package is now back to serving a single purpose:
representing a weldr blueprint. It does not depend on the `pipeline`
package anymore.
Change osbuild-composer and osbuild-pipeline to use the new API,
hard-coding "fedora-30". This looks a bit weird now, but is the same
behavior as before.
All test cases now also take an "distro" key in the "compose" object.
This tool outputs the pipeline associated with each output type. In
the future this should grow to take a blueprint as an input, and
also allow the arch/os/version/variant to be configured.
Signed-off-by: Tom Gundersen <teg@jklm.no>
