“Open Build Service is a generic system to build and distribute packages from sources in an automatic, consistent and reproducible way.”
openSUSE distributions’ build system is based on a generic framework named Open Build Service (OBS), I have been using these tools in my work environment, and I have to say, as Debian developer, that it is a great tool. In the current blog post I plan for you to learn the very basics of such tool and provide you with a tutorial to get, at least, a Debian package building.
The figure above shows Open Build Service, from now on OBS, software architecture. There are several parts which we should differenciate:
- Web UI / API (obs-api)
- Backend (obs-server)
- Build daemon / worker (obs-worker)
- CLI tool to manage API (osc)
Each one of the above packages can be installed in separated machines as a distributed architecture, it is very easy to split the system into several machines running the services, however in the tutorial below everything installs in one machine.
The backend is composed of several scripts written either in shell or Perl. There are several services running in the backend:
- Source service
- Repository service
- Scheduler service
- Dispatcher service
- Warden service
- Publisher service
- Signer service
- DoD service
The backend manages source packages (any format such RPM, DEB, …) and schedules them for a build in the worker. Once the package is built it can be published in a repository for the wider audience or kept unpublished and used by other builds.
System can have several worker machines which are encharged to perform the package builds. There are different options that can be configured (see /etc/default/obsworker) such enabling switch, number of worker instances, jobs per instance. This part of the system is written in shell and/or Perl language.
WEB UI / API
The frontend allows in a clickable way to get around most options OBS provides: setup projects, upload/branch/delete packages, submit review requests, etc. As an example, you can see a live instance running at https://build.opensuse.org/
OSC is a managing command line tool, written in Python, that interfaces with OBS API to be able to perform actions, edit configurations, do package reviews, etc.
Now that we have done a general overview of the system, let me introduce you to OBS with a practical tutorial.