[sf-perl] What version of perl and what OS do you use? [poll]

Michael Friedman friedman at highwire.stanford.edu
Thu Feb 4 14:57:01 PST 2010

On Feb 4, 2010, at 2:42 PM, Greg Lindahl wrote:
> We don't update to the latest versions of new CPAN modules very often
> since that's caused some regressions that annoyed us.
> I'd be curious how other people who run big production websites deal
> with versioning.

Yeah, we've run into some regressions too. After the first disaster or so, we decided that we'd do all CPAN installing on a totally separate machine and then run a bunch of tests against it to make sure it didn't break anything. The downside is that this procedure can take a week or more for something big or which has installation problems. So we only bother with the whole procedure for big things.

For example, we've tried to upgrade our 5-year-old copy of libxml2/XML::LibXML for a couple of years now, but every time we have compile errors, regression problems, and just painful testing, so we haven't actually succeeded yet. This is problematic because our version (1.58) doesn't have any XPath support in it and the developers (me!) really want that. But, since we can't make it install and not break things, we can't do it. I'm sure we'll try again this summer and maybe it'll get through this time.

On the other hand, adding new modules we do directly on our master copy. I give it a little test and then distribute out to all the servers. Then the developer can give it a whirl and make sure everything works fine. Since it's brand new, we know that nothing else is using it yet. 

I would highly recommend keeping around one extra production-setup server to do this sort of testing on. We use whatever "hot spare" we have at the time. If it has to go into production, the sysadmins wipe out my CPAN testing by recopying over the master perl libs and then I have to start from scratch again with the next free machine. But we can't afford to have a complete server just sitting around doing nothing, so oh, well.

-- Mike
Mike Friedman | HighWire Press, Stanford Univ | friedman at highwire.stanford.edu

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