Enabling updates-testing and epel-testing repositories when using Copr

Copr is a really useful Fedora community build service which also hosts dnf/yum repositories of the built packages.

When creating a Copr project, one can specify which chroots, i.e. which distribution version and architecture combinations, to enable. Examples of chroots are fedora-27-x86_64, epel-7-ppc64le, fedora-rawhide-i386 etc.

However, there is no easy to use option to enable testing repositories, e.g. the updates-testing repository for Fedora Branched and stable releases, when specifying the chroots. Let me show you how you can easily achieve that by specifying an extra repository with a parameterized URL.

When setting up a Copr project, one can also specify extra repositories to enable (in the web UI, they are referred to as External repositories).

A nice feature of Copr is that the URLs of these extra repositories can be parameterized with variables representing the name of the distribution ($distname), release version ($releasever) and base architecture ($basearch).

Using that, we can easily specify an extra repository that will correspond to the appropriate testing repository of any given chroot.

Unfortunately, Fedora and EPEL don't use the same directory structure, so one can't use the same parameterized extra repository URL.

If you want to enable the updates-testing repository in a Fedora chroot, add the following extra repository URL to your Copr project:

http://download.fedoraproject.org/pub/$distname/linux/updates/testing/$releasever/$basearch/

If you want to enable the epel-testing repository in an EPEL chroot, add the following extra repository URL to your Copr project:

http://download.fedoraproject.org/pub/$distname/testing/$releasever/$basearch/

To do this using Copr command line interface, run the following:

copr-cli modify --repo '<parameterized-extra-repository-URL>'

For example, to enable the updates-testing repository in a Fedora chroot, run:

copr-cli modify --repo \
    'http://download.fedoraproject.org/pub/$distname/linux/updates/testing/$releasever/$basearch/'

If your Copr project includes a Fedora and an EPEL chroot, just add both, the updates-testing and the epel-testing repository, as extra repositories.

A build of the Copr project in a Fedora chroot will fail to fetch the information about the (non-existent) epel-testing repository, but it will successfully continue. The same goes for a build in an EPEL chroot or a Fedora rawhide chroot, which don't have a corresponding updates-testing repository.