The fedora project uses koji for their build system, as do several other projects.

koji's goal is to provide a flexible, secure, and reproducible way to build software.

key features:

- new buildroot for each build
- robust xml-rpc apis for easy integration with other tools
- web interface with ssl and kerberos authentication
- thin, portable command line client
- users can create local buildroots
- buildroot contents are tracked in the database
- versioned data
this package contains the common python library used by other components.