In my Jenkins setup, I've decided to bypass the build number with regards to the RPM version numbering completely. Instead, I use a home-made script that generates and keeps track of the various releases that are being generated.
In my spec file:
Version: %{_iv_pkg_version}
Release: %{_iv_pkg_release}%{?dist}
And in the Jenkins build script:
# Just initialising some variables, and retrieving the release number.
package="$JOB_NAME"
# We use setuptools, so we can query the package version like so.
# Use other means to suit your needs.
pkg_version="$(python setup.py --version)"
pkg_release="$(rpm-release-number.py "$package" "$pkg_version")"
# Creating the src.rpm (ignore the spec file variables)
rpmbuild --define "_iv_pkg_version $pkg_version" \
--define "_iv_pkg_release $pkg_release" \
-bs "path/to/my/file.spec"
# Use mock to build the package in a clean chroot
mock -r epel-6-x86_64 --define "_iv_pkg_version $pkg_version" \
--define "_iv_pkg_release $pkg_release" \
"path/to/my/file.src.rpm"
rpm-release-number.py is a simple script that maintains a file-based database (in JSON format, for easy maintenance). It can handle being run at the same time, so no worries there, but it won't work if you have build slaves (as far as I can tell, I don't use them so can't test). You can find the source code and documentation here.
The result is that I get the following package versioning scheme:
# Build the same version 3 times
foo-1.1-1
foo-1.1-2
foo-1.1-3
# Increment the version number, and build twice
foo-1.2-1
foo-1.2-2
PS: Note that the Jenkins build script is just an example, the logic behind creating the rpmbuild directory structure and retrieving the .src.rpm and .spec file names is a bit more complicated.
