Adding chapter Packaging of Python RPMs

[Daskyleia]

Resolving BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1429422

This chapter is WIP. Please add any comments to help me make this chapter more informative.

[hroncok]

I don't see a benefit of this guide. It has Fedora specific links, a RHEL 6/7 specfile example without explanation and that's it.

[hroncok]

But the tool doesn't support RHEL 7 specfiles. Only Fedora or EPEL.

[hhorak]

@hroncok what is the difference between epel and rhel then?

[hroncok]

Backported Fedora macros. Python 3.

[xsuchy]

It does support epel. pyp2rpm -o epel6 and similary for epel7

[hroncok]

Yes. But not plain RHEL.

[Daskyleia]

I can write this in conditionals to make it visible only in community version of the guide, not in the RHEL one.

[hroncok]

Again, the spec file above is RHEL 6/7, but the link is for Fedora. That is very different currently and rather confusing.

[hhorak]

Are there at least some macros the same?
Anyway, we might pick at least the macros from the example, and either use the description from Fedora, or write a new one. I don't think we need as comprehensive guide for RHEL, as we have for Fedora, a simple variant should work.
Another thought regarding this is that Fedora macros will be relevant for the next major version of RHEL, so it's also question what RHEL version this guide is focused on..

[hroncok]

Not really. They all got python version number in Fedora.

[hroncok]

What RHEL version we target has never been answered to me.

[Daskyleia]

It is written for RHEL7 (RHEL version) and for Fedora (community version) under conditionals. Other versions of RHEL might be written in different paragraphs stating for which version they are written in their headings. The above link to macros was only WIP. I would like to see several most used and useful macros for RHEL7 and for Fedora. We do not need to document them all. Can you please suggest the most used macros for RHEL7 and for Fedora (separately)?

[hhorak]

Actually I like it is short, and using links to other sources looks like a good way to me. I just added small comments, but generally I think this could be good enough.

[hhorak]

I'd maybe add some thinking about comparison with working with native python packages, like:
In comparison to native python packages from Python Package Index, RPM allows to specify dependencies on other RPMs, that are not necessary Python packages, RPM also allows to use cryptographic signing to verify content, and deliver packages that are integrated and tested ahead with the rest of the system. On the other hand RPM does not allow users to install Python software as a non-root user or to an arbitrary location.

[Daskyleia]

Thank you, good idea.

[hhorak]

I'd just add a note that some manual corrections may be necessary, to not set too high expectations.

[Daskyleia]

"Pyp2rpm is still in development. Some manual corrections might be necessary."

[hhorak]

Internally, we also have this Packaging guide available as part of the RHSCL documentation, so internally we should like there.

[Daskyleia]

It will be done.

[Daskyleia]

Could you please make a suggestion what are those modules and what does "pure" means?

[hroncok]

python modules https://docs.python.org/2/tutorial/modules.html

pure python - written only in Python (as opposed to extension modules compiled from languages like C, C++ or Fortran)

[xsuchy]

This seems to be stuck. Can you please rebase it? And make it up to date (python3)?

[xsuchy]

@Daskyleia ping

[hroncok]

@xsuchy I think that @Daskyleia has left Red Hat years ago and never used GitHub since, the profile page shows no activity after this PR.

[xsuchy]

@hroncok thank you. Is someone from the python team willing to finish it, or is it doomed to be closed?

[hroncok]

I am afraid I still don't understand the purpose of this guide. Do we still need a guide for packaging for RHEL 7? Or is it RHEL 8 now? Or even RHEL 9? Those guides would be different. Essentially this repo says in the README:

Many of the guides I have found around the internet are ... simply showing their age and contain old, incorrect or outdated information.

Yet the pello.spec example would not even build on anything newer than RHEL 7.

What is the purpose of this guide? Who is the target audience and what type of Python software do they package for what distributions?

[xsuchy]

My ultimate goal was to hopefully get rid of RPM Max one day. Which we still have to reference because it is only source for some parts.
The more noble goal is to provide a guide for someone who starts with packaging from scratch.

The guide can generate artifacts for upstream and for RHEL. E.g., see https://github.com/redhat-developer/rpm-packaging-guide/blame/master/source/advanced-topics.adoc#L611

The guide should be introductory and is meant for beginners. Speaking of python I would keep it as minimal as possible and reference the Python section from Fedora Packaging Guidelines.

[hroncok]

I have no idea what RPM Max is and I was unable to Google it, as it seems to be the name of some kind of a dagger 🗡️

The Python section from Fedora Packaging Guidelines is not present-RHEL compatible. If you target RHEL 9+ only, feel free to do so, but in the next years, it might not be RHEL9 compatible either.

There is also https://docs.fedoraproject.org/en-US/packaging-guidelines/Python_201x/ which is more or less compatible with EPEL 8, but not entirely and not with pure RHEL 8. It is extremely incompatible with RHEL 7.

The more noble goal is to provide a guide for someone who starts with packaging from scratch.

Something like this? https://docs.fedoraproject.org/en-US/quick-docs/creating-rpm-packages/

The guide can generate artifacts for upstream and for RHEL...

An if RHEL knob is certainly nice for small differences, but for Python, it would essentially be:

if RHEL 7:
  here be a guide
elif RHEL 8:
  here be a different guide
elif RHEL 9 or Fedora:
  here be a link to Fedora's Python packaging guidelines
endif

I'd like to help here, but I still don't understand what kind of a guide you are looking for (and I didn't understand that 3 years ago either). Back to my question:

Who is the target audience and what type of Python software do they package for what distributions?

You said they are beginners. But what are they trying to accomplish? I cannot imagine a simple "beginners' guide to packaging Python RPM packages" because the topic is too wide. There might be "simple" guides for straightforward tasks, e.g.:

• taking a Python library package from PyPI (or an internal Python package index) and turning it into an RPM package for RHEL 8
• taking a Python 3 application package from PyPI and turning it into an RPM package for Fedora 33+
• taking a standalone Python 2 script and packaging it into an RPM package for RHEL 7 (that's more or less what pello.spec does now, in a weird but hopefully functional way)

[hroncok]

I have no idea what RPM Max is and I was unable to Google it, as it seems to be the name of some kind of a dagger dagger

Oh, http://ftp.rpm.org/max-rpm/

[pmkovar]

I should add here that this guide hasn't received many updates since the RHEL7 times. Downstream writers also decided on not syncing this with the RHEL8 documentation anymore, so since the RHEL8 release it's been essentially out of sync. At this point it might be wise to scrap the RHEL7 parts and focus on the latest RHEL and Fedora, if there's interest to continue updating it. Starting updating it against the current RHEL8 doc might also be an option. For Python, I see there's e.g.: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/packaging_and_distributing_software/advanced-topics#assembly_packaging-python-3-rpms_advanced-topics

[xsuchy]

Something like this? https://docs.fedoraproject.org/en-US/quick-docs/creating-rpm-packages/

Yes. But more verbose :)