This is a tool to manage an "overlay" of packages on top of a base distribution, where the upstream sources come from upstream git, and the spec files are automatically edited. The output is a single yum repository.

It is designed to be useful both for developers locally, as well as a fully automated service.

A comparison with http://copr.fedoraproject.org/ is useful. COPR could be described as "a web UI on top of mockchain using OpenStack for builds". A major difference then is rpmdistro-gitoverlay just uses raw mock chains - it applies the same security to builds as regular Koji/Brew does (i.e. build inputs must be fully trusted).

COPR takes SRPMs as input - there are other projects to do the git -> SRPM stage, whereas rpmdistro-gitoverlay does that internally.

COPR is also a service with both a UI and an API, whereas rpmdistro-gitoverlay is designed with its sole input to be a YAML file, stored in a git repository. It will attempt to synchronize state to whatever is specified in the YAML file.

For example, if you delete a source from the overlay, all RPMs generated from that source will also drop out of the generated repository. Whereas COPR is a stateful system.

# An example overlay file

aliases: 
  - name: github
    url: git://github.com/

  - name: gnome
    url: git://git.gnome.org/

  - name: fedorapkgs
    url: git://pkgs.fedoraproject.org/

distgit:
  prefix: fedorapkgs
  branch: master
  
root:
  mock: fedora-rawhide-x86_64

cache:
  buildserial: 0

components:
  - src: gnome:ostree

  - src: github:hughsie/libhif
    freeze: 07fb582c331773ea8ee60513d8ee74f592a7eab9
    distgit: 
      name: libhif
      patches: drop

  - src: github:projectatomic/rpm-ostree
    distgit:
      name: rpm-ostree
      patches: drop

Create a working directory where the primary data src/ and rpms/ will be stored, and copy your overlay.yml in there (or symlink it to a git checkout):

mkdir -p /srv/build
ln -s ~walters/src/fedora-atomic/overlay.yml .

Now, we perform a resolve: This will generate a src/ directory which is a git mirror of all inputs (recursively mirroring submodules), and take a snapshot of exact commits into snapshot.json

rpmdistro-gitoverlay resolve --fetch-all
ls -al snapshot.json

Now, let's do a build:

rpmdistro-gitoverlay build

This will generate rpms/, which is a yum repository. Note however the system is idempotent, if we run again:

rpmdistro-gitoverlay build

Nothing should happen aside from a createrepo invocation.

The code in this project originated from https://github.com/redhat-openstack/rdopkg as a baseline; however it is (will become) rather different.

See also https://fedoraproject.org/wiki/Layered_build_scripts_for_package_maintainers for a collection of other projects.