Monthly Archives: March 2011

Matching IPv6 addresses with Regexp::Common

I wish Regexp::Common had a $RE{net}{IPv6} regular expression, but it doesn't (yet).

So I tried to implement this myself, but ripped off the IPv6 matching bit from the existing Regexp::IPv6 which happens to have a working IPv6 regular expression with a reasonable test suite. Now, why Regexp::IPv6 is not part of Regexp::Common?

By the way, I'll copy/paste the full regular expression to match IPv6 addresses, just for fun:


Of course, I will never be able to tell if it's right or wrong, but the fact is that it passes the test suite :)
However, the actual code is not like that: it generates the full regular expression from a few components. Anyway, I've pushed a ipv6 branch on my fork of Regexp::Common. I hope it will be included soon in Regexp::Common or improved it enough to be included in it, so we can finally match IPv6 addresses with:

use Regexp::Common;

my $addr = '2001:0db8:0000:0000:0000:0000:1428:57ab';
if ($addr =~ $RE{net}{IPv6}) {
    print "Yes, it is an IPv6 address";
else {
    print "No, it isn't";

“Loadsnake” AKA the Novell Netware snake screensaver clone

For those that didn't have the pleasure to see the old Novell Netware snakes screensaver, I'll say here that it was the default Netware screensaver, in console/text mode. It showed one snake for each CPU you had (99.9% of people had just 1 really). The cool thing is that the snakes became longer and longer as your server load increased. They also started going faster.

Anyway, this is one of those little time-wasting projects that usually go nowhere. I started working on a clone of this Netware screensaver in 2007. I remember I wanted to figure out how to write an xscreensaver "hack", so I spent a weekend looking at the source code for all the existing hacks, and I picked popsquares.c as a base and started tearing it apart, injecting dubious amounts of crappy C code until it did what I wanted.

Fast forward 4 years. Yesterday, for some reason, I got back to it, cleaned up the code a bit, and implemented a "fantastic" new feature I've always wanted: different snake colors for every different CPU, instead of all snakes being red. So I did, and the result is, well, see it for yourself:

Source code, but don't take inspiration from it, please… :) is up on github at You can also download the xscreensaver binary module if you want (only for Linux x86_64), as compiling it requires a bit of fiddling on the xscreensaver source code.

I have to admit that it's cool to run your own screensaver :)

Continuous integration of Perl-based projects in Hudson/Jenkins

I didn't find massive amounts of information about how to link any Perl-based project to Jenkins for continuous integration, but there's a few presentations on Slideshare that carry some nice ideas.

While some older pages say that "there's no out-of-the-box integration, etc…", I think there is. A very simple, very straight-forward way to integrate any (Perl) project that uses TAP into Jenkins.


Here we go then:

TAP::Harness::JUnit will capture all the standard TAP output and turn it into the default JUnit XML output that Jenkins expects. And you don't need to do anything to make this happen. How cool is that? Read below.

Build instructions

You need to instruct Jenkins on how to build your project. So, in the "Build" panel, I usually put:

prove -I ./lib -v

If you don't use prove, be ashamed and start using it :) You'll never look back. So, getting Jenkins to understand TAP is just a matter of modifying that command to read:

prove -I ./lib -v --harness=TAP::Harness::JUnit

Here's the actual Build panel screenshot:

That's it. prove will produce a junit_output.xml file with the JUnit-compatible XML output that corresponds to the standard TAP output.

Post-build actions

Now you need to tell Jenkins that the file is actually there. I'm not sure why, but this is not automatic. You need to tell it to "Publish JUnit test results". Now, if you ask me that's totally surprising, but it works. So:

That should be it. Run your build and you should see your tests output picked up.