AllGoodBits.org

cpanspec

cpanspec is used by the Fedora distribution's perl module package maintainers as at least a starting point to automatically generate rpm spec files from CPAN. Unfortunately, a cpanspec package it wasn't just available for the CentOS version that I was using, so I had to get it myself (it's just a perl script, but I had to install some dependencies by hand/cpanm). To create a package for the perl module Foo::Bar, I use it something like this:

cpanspec --license --packager 'Duncan Hutty <dhutty@allgoodbits.org>'  --verbose   --follow Foo::Bar

Fixing the specfile is usually a twofold task: ensure that all installed files are packaged and correct the Requires.

Installed (but unpackaged) file(s) found:
/usr/bin/envpath
/usr/share/man/man1/envpath.1.gz

%{_bindir}/envpath
%{_mandir}/man1/*

%{?filter_setup:
%{?perl_default_filter}
}

%filter_from_provides /Clipboard::Win32/d
%filter_from_provides /Clipboard::MacPasteboard/d
%filter_from_requires /Win32::Clipboard/d
%filter_from_requires /Mac::Pasteboard/d
%filter_setup

cpan2dist

Another possibility here is: cpan2dist. I list this because it's more easily available and sometimes it's been good enough for me, but as I've needed more and more perl modules, I've found that cpanspec has been working better for me.

cpan2dist --format CPANPLUS::Dist::RPM \
          --default-ignorelist \
          --default-banlist \
          --ignore Devel::StackTrace \
          --ignore Data::Dumper \
          <module to build>

Building the RPM

rpmbuild -ba perl-Foo-Bar.spec

Add the rpm to a local repository

for r in `ls ~/rpmbuild/RPMS`;
  do
    createrepo -d ~/rpmbuild/RPMS/${r}
  done

And then ensure that your ~/rpmbuild/RPMS is served by your installation server as the rootdir of your local yum repo

local::lib

local::lib provides a local lib directory that we can fill with the exact versions of various perl modules that we want to reduce the chance of problems from conflicts and/or dependency hell.

The only constraint imposed on the developer is the requirement for a use pragma according to which version of the module library is desired::

use local::lib '/usr/local/perl/best' use local::lib '/usr/local/perl/35

Installing into local::lib with cpanm

Trivial:

cpanm -L <directory> <module to install>

Getting local::lib dirs in place

In this case, I'm using puppet for configuration management, so for each application server, puppet knows which perl module directories are required. I also have puppet create a symlink to the newest:

ls -l /agb/perl
total 0
drwxr-xr-x 2 root root 40 Jan  9 10:19 12
drwxr-xr-x 2 root root 40 Jan  9 10:19 3
drwxr-xr-x 2 root root 40 Jan  9 10:19 5
drwxr-xr-x 2 root root 40 Jan  9 10:19 8
lrwxrwxrwx 1 root root  2 Jan  9 10:19 best -> 12

This means that on a development machine, devs/apps can ask for the latest versions that I have published and know that they're developing against the latest edge, but when we come to deploy, we can lock to a particular set of module versions for stability. Here's how to ask::

use local::lib '/agb/perl/best' use local::lib '/agb/perl/3'

Multiple versions of perl

In order to take care of the possible requirement for multiple versions of perl, we can push the above structure down one level and use some other symlink magic for versions numbers:

ls -l /agb/perl
total 0
   drwxr-xr-x 2 root root 40 Jan  9 10:19 5.10.1
   drwxr-xr-x 2 root root 40 Jan  9 10:19 5.12.4
   lrwxrwxrwx 1 root root  2 Jan  9 10:19 best -> 5.12.4

ls -l /agb/perl/5.10.1
total 0
   drwxr-xr-x 2 root root 40 Jan  9 10:19 1
   drwxr-xr-x 2 root root 40 Jan  9 10:19 2
   drwxr-xr-x 2 root root 40 Jan  9 10:19 4
   drwxr-xr-x 2 root root 40 Jan  9 10:19 6
   lrwxrwxrwx 1 root root  2 Jan  9 10:19 best -> 6

ls -l /agb/perl/5.12.4
total 0
   drwxr-xr-x 2 root root 40 Jan  9 10:19 12
   drwxr-xr-x 2 root root 40 Jan  9 10:19 3
   drwxr-xr-x 2 root root 40 Jan  9 10:19 5
   drwxr-xr-x 2 root root 40 Jan  9 10:19 8
   lrwxrwxrwx 1 root root  2 Jan  9 10:19 best -> 12

If you're going to take this approach, here's how to ask::

use local::lib '/agb/perl/best/best' use local::lib '/agb/perl/5.10.1/2'