[CentOS-devel] Building python38-createrepo_c in CentOS 8 Stream

Wed Mar 2 10:44:10 UTC 2022
Miro Hrončok <mhroncok at redhat.com>

On 02. 03. 22 11:16, Ewoud Kohl van Wijngaarden wrote:
> Hello everyone,


> I'm sending this on behalf of the packagers of the Pulp project.
> The Pulp project uses createrepo_c and in particular the Python bindings. The 
> appstream repository does contain python3-createrepo_c but Pulp needs Python 
> 3.8 so it uses the 3.8 module. There is no python38-createrepo_c so for now 
> we're building it ourselves. The problem shows up when createrepo_c is bumped 
> in CentOS Stream. From repoclosure:
> Depsolve Error occured:
>   Problem: package python38-createrepo_c-0.17.7-3.2.el8.x86_64 requires 
> createrepo_c-libs = 0.17.7-3.2.el8, but none of the providers can be installed
>    - cannot install both createrepo_c-libs-0.17.7-4.el8.x86_64 and 
> createrepo_c-libs-0.17.7-3.2.el8.x86_64
>    - cannot install both createrepo_c-libs-0.17.7-3.2.el8.x86_64 and 
> createrepo_c-libs-0.17.7-4.el8.x86_64
>    - cannot install the best update candidate for package 
> python38-createrepo_c-0.17.7-3.2.el8.x86_64
>    - cannot install the best update candidate for package 
> createrepo_c-libs-0.17.7-3.2.el8.x86_64
> It would be ideal if CentOS itself built python38-createrepo_c (and possibly 
> also for other Python modules). Is this something that could be done?

Technically yes, but that depends on RHEL business decisions.

If you want to build your own, I think there are two fundamentally different 
ways to build python38-createrepo_c in c8s.

The first way, that I would use for example in EPEL 8, is to create a 
python38-createrepo_c component, build the package in there, but not ship 
createrepo_c-libs at all, but depend on the official one. If you could share 
your spec file, I can send you an updated version that will do this and fix the 
dependency thing. You will however need to keep it more or less synced with the 
baseline createrepo_c package whenever it is updated in RHEL / c8s.

The other way is to namespace the C library on the filesystem and/or include 
the C library in the Python package.

E.g. instead of /usr/lib64/libcreaterepo_c.so.0.X.Y have something like 

That requires some changes to make sure the library is found (possibly rpath) 
but allows you to diverge from the official createrepo_c package version (both 
updating to newer or letting an old not-updated version rot there as long as it 

Both approaches have advantages and disadvantages.

Miro Hrončok
Phone: +420777974800
IRC: mhroncok