It is a web service for building OS images. The core of osbuild-composer, which is common to all APIs, is osbuild manifests generation a job queuing. If an operating system is to be supported by osbuild-composer, it needs the manifest generation code in internal/distro directory. So far, we only focus on RPM based distributions, such as Fedora and RHEL. The queuing mechanism is under heavy development at the moment.

Interfacing with dnf package manager

We use our custom wrapper for dnf, which we call simply dnf-json, because its interface goes like this:

  • Stdin - takes a JSON object
  • Stdout - returns a JSON object
  • Return code is used only for dnf-json internal errors, not for errors in the operation specified on the input. Those errors are reported in the returned JSON object.

Local API - Weldr

This API comes from the Lorax-composer project. osbuild-composer was created as a drop-in replacement for Lorax which influenced many design decisions. It uses Unix-Domain socket, so it is meant for local usage only. There are two clients:

Activate this API by invoking systemctl start osbuild-composer.socket. Systemd will create a socket at /run/weldr/api.socket.

Remote API - Cloud API

This is the /api/image-builder-composer/v2/ API endpoint. There are currently two clients, which are integrating with osbuild-composer using this API: