NLOpt library for rhel is not available in rosdep

[juanscelyg]

Hi guys,

Currently, we are working in a release for Easynav_plugins. For a package we have as dependency NLOpt, which one is available for ubuntu and more. However, this library is not available for rhel.

I was checking if it is possible to install from repos in Almalinux (distro used in Buildfarm) but there is not candidate.

In this case, how it is the correct way to use a library/dependecy not available in repos using rosdep? or Is it possible to add nlopt tag for rhel using another method?

Grettings!

[mjcarroll]

Well, this was on me to actually write a document about and it became low priority as there was less need over time (#41221)

I think generally, this would be a reasonable place to use a vendor package. You could do something like nlopt_vendor and put it in your repository. What we typically do in this case is try to vendor a version that exactly matches what is on the corresponding Ubuntu distro, and the vendoring becomes a "no-op" on platforms that have the correct version. On platforms that don't have the version, it will be built from source. This is handled by ament_cmake_vendor_package, and you can find several example of use here: https://index.ros.org/p/ament_cmake_vendor_package/#rolling-deps

[mjcarroll]

I was checking if it is possible to install from repos in Almalinux (distro used in Buildfarm) but there is not candidate.

I think the answer is no, but tagging in @cottsay who knows things.

[cottsay]

Indeed NLopt is not available for RHEL 8/9/10 at the moment. You could submit a package build request to EPEL asking the Fedora maintainers to expand support to RHEL, but there appear to be prerequisite packages missing as well.

At this point, the ball is really in your court. RHEL isn't a required platform for ROS 2 so it's fine to disable the builds of your package on RHEL and continue to ship only for Ubuntu.

As @mjcarroll mentioned, it is possible to use a vendor package as well.

[fmrico]

so it's fine to disable the builds of your package on RHEL and continue to ship only for Ubuntu.

@juanscelyg Maybe we could explore this. If someone wants to use the EasyNav plugin which use NLOpt, in RHEL they can use the sources or the Pixi way.