Question

I want to setup in-house CPAN for distributing our internal code.

So I was looking at CPAN::Mini as recommended here. But it looks there are other options as CPAN::Site, CPAN::Dark, Dist::Zilla …

I’m little bit overwhelmed with all these options. What do people mostly use/ recommend?

What I need is a way to push internal modules to repository which can be accesses from several machines.

Answer 1

The quick answer is that you want to use CPAN::Mini to create a local mirror of all that is current on the CPAN, and then CPAN::Mini::Inject to add your own distributions to it.

The long answer is that it helps to understand how a CPAN mirror is constructed. Broadly speaking, it is simply a directory that contains two sub-directories.

The ‘modules’ directory contains in turn two files, 03modlist.data.gz, whose contents is ignored by modern CPAN clients but there’s legacy code that assumes this file exists, so just copy it from an existing mirror. The other is 02packages.details.txt.gz, which I shall describe later.

The ‘authors’ directory contains a file ’01mailrc.txt.gz’ which is another relic of the past whose contents can be ignored, so just copy it from another mirror, and it contains the ‘id’ directory. This in turn contains sub-directories and distributions, whose names follow a pattern. For example, my PAUSE id is DCANTRELL, and one of my distributions is XML-Tiny-2.06.tar.gz, so that file lives at …/authors/id/D/DC/DCANTRELL/XML-Tiny-2.06.tar.gz.

The 02packages.details.txt.gz file is the index that maps module names to distributions, and this must be up to date for your mirror to work properly. It consists of a few header lines, which must be present and correct, followed by a blank line, followed by one line for each module. Those lines are three fields separated by spaces:

• module name
• module version
• distribution filename

eg

  XML::Tiny 2.06 D/DC/DCANTRELL/XML-Tiny-2.06.tar.gz

(you may also see .tgz, .zip, and a coupla others)

A distribution may appear in several lines, once for each module it contains. eg

  XML::Tiny::DOM 1.1 D/DC/DCANTRELL/XML-Tiny-DOM-1.1.tar.gz
  XML::Tiny::DOM::Element 1.1 D/DC/DCANTRELL/XML-Tiny-DOM-1.1.tar.gz

In a normal CPAN mirror, there may be several versions of a distribution, and several versions of a module – for example, the current version and a few older ones, or the current stable one and a dev one. The index file contains the most recent stable version. You can tell dev versions of distributions because they have an underscore in their version, or contain the string ‘-TRIAL’.

So, knowing all that, you can construct a CPAN-a-like that contains only your code. But using CPAN::Mini and CPAN::Mini::Inject to add your stuff to a “real” CPAN is less work.

Once you’ve created your CPAN-a-like, you can either expose it on HTTP and access it using any client as normal, or you could just have it in the filesystem and configure the CPAN client to access it using a file:/// URL.