Wednesday, September 2, 2009

MooseX::AttributeHelpers is dead, long live Moose::Meta::Attribute::Native

Version 0.89_01 of Moose is out, featuring the well-loved MooseX::AttributeHelpers module under a new name. See Moose::Manual::Delta for a summary of changes; the functionality should be almost identical, but some API changes were made to bring the helpers more into line with the rest of Moose (e.g. handles instead of provides).

If you're using MXAH, please grab this dev release and see how your code works when you port it over to the Native traits. Please let us know if there are any problems!

We started work on this at the YAPC Moose Hackathon. We'd talked forever about how we'd move a MooseX module into the Moose core if everyone agreed it was the right way to do things, but it hadn't ever happened. Rob Buels (rbuels) and Jay Hannah (jhannah) helped out with some tedious but necessary work at YAPC -- converting examples and tests -- and Jesse Luehrs (doy), Chris Prather (perigrin), and Shawn Moore (Sartak) have worked on the code and generally helped keep momentum going since then (reviewing commits, doc fixes, and so on).

Cheers to you all, and thanks for your great work.

Tuesday, July 28, 2009

webmachine: intriguing

A few days ago, rjbs pointed me at Webmachine, "a REST-based system for building web applications".

Its central concept is a pretty mind-blowing inversion of control compared to I'm used to in Catalyst-Action-REST. Webmachine says that there's only one way to handle a request to a particular resource. That means that you don't write any of the logic to decide what status code to return -- you write a bunch of hooks that let Webmachine decide it for you. Similarly with content type (both request and response), etag, etc. -- here's the full list.

Webmachine's still sinking into my brain, so I haven't gotten my mind around how it might be done in Perl, let alone how it'd fit into something like Catalyst -- Webmachine also has a URL dispatching mechanism, but it seems to be almost entirely separable from the resource dispatching mechanism (the HTTP graph, above). I'm looking forward to playing around with these ideas more, though, because Webmachine seems to solve a few of the architectural problems I was having with C-A-REST.

Friday, July 24, 2009

back in the saddle

Almost exactly a month after being laid off, I've accepted a job with Grant Street Group. Schwern pointed me in their direction when we were both at YAPC, and I'm glad he did; everything I've experienced with them so far has been positive, and I'm excited to be starting with them (on Monday!).

This also means that we'll be moving back to the East Coast, this time to Pittsburgh. I'll be telecommuting, but while our time in Portland has been fun and Portland is a very enjoyable city, the fact is that we've also really missed being able to visit family without spending a thousand dollars and two days in a plane each time.

The next month is going to be crazy -- our goal is to be in Pittsburgh by September 1st, and between moving and starting a new job, I'm not sure how much time I'll have for blogging or hacking on personal projects. I promise I'll try to pick everything back up as soon as possible!

Thursday, July 9, 2009

YAPC wrapup

I know this post is a bit late, but I was busy after YAPC dealing with my unexpected unemployment. Sorry!

YAPC is always great for reconnecting with people who've been just words on a screen for the last year. rjbs and I managed to get a room together, so much hilarity ensued; the first thing he greeted me with when I arrived was "I've been avoiding working on slides by reading Wikipedia articles about Spider-Man's Clone Saga. Let me tell you all about it!" (Since I also needed to avoid working on my own slides, this was a welcome diversion.)

I always feel a little skeptical about the arrival dinner. It's always loud and expensive and the food is often merely adequate. Rik and I showed up, but didn't stick around for very long, since we'd almost exhausted our store of slide-avoidance time.

Monday I gave two talks, about CPAN packaging and deployment and a quick overview of Dist::Zilla and its workings. I wasn't sure how they'd be received, since this was my first time speaking at YAPC, and it's a little more intimidating than talking in front of a local Perl Mongers group. Both went well, though, and it was gratifying to hear people saying "I'm totally going to use that!"

It was between those two talks that I got the call from OpenSourcery: "This is Brian, with Josh and Kris; can you please call me back as soon as possible?" My first thought was, "Well, I don't have a job anymore. I guess I need to call them back to find out why." It's hard to imagine a better time and place to be laid off than the first day of YAPC, though, with all the networking possibilities (and fellow hackers to buy me consolatory beers).

Monday night I felt feverish and lethargic, and Tuesday morning's talk on Moose roles and type constraints was difficult to get through. I ended 10 minutes early, partly because I didn't have the energy to explain all the examples as much as I had expected to. I went straight back to the dorm afterwards and slept for an hour and a half. This helped immensely.

Tuesday evening's auction and dinner was one of the better ones I can remember. First, I happened to sit at a table full of Canadians, several of whom I found I already knew (Adam Prime, Michael Graham), and we had a fun conversation about all sorts of random things the whole evening. Second, unlike many years, the auction did not drag on interminably, so we had plenty of time for said fun conversation without the mental overhead of having to tune out Uri's haranguing voice.

I barely remember Wednesday, except that Karen called me out during her talk for something I said on Twitter (and a followup from Rik), which caught me by surprise for some reason. Maybe I'm not really used to the idea that people actually read the things I write in public places.

Talks I really enjoyed:

Thursday was the Moose Hackathon, which was a great time that I will address in more detail in another post. I think the highlight may have been watching Rob fall off his chair laughing not once but twice.

My summary from twitter, still true:

despite everything going on with my (lack of) work, probably one of my favorite years

Friday, July 3, 2009


Last Monday, I and 6 or 7 others were laid off from OpenSourcery. I'd just given my first talk at YAPC, and I wasn't really expecting to find out that I didn't have a job anymore. Whoops! If anyone wants to hire an experienced Perl programmer, take a look at my resume.

I'm going to try to fill most of my unemployed time with work on Moose and Catalyst. I'd been working on CPANPLUS::Dist::Deb, but that's much less compelling without a work environment to target -- luckily, I think Josh ben Jore is going to pick up a lot of my slack.

Meanwhile, I'm rebooting my blog here. I'll fill in old posts from OpenSourcery and try to get back into the Iron Man challenge.

Friday, June 5, 2009

Packaging CPAN Modules for Debian

I'm giving a talk on CPAN at this year's YAPC in Pittsburgh. One of the things I plan to mention is the cpan2dist program from CPANPLUS. I use cpan2dist (with CPANPLUS::Dist::Deb) to build Debian packages for our internal use.

I had a conversation on IRC this morning with someone who asked, roughly, "What's the difference between cpan2dist and dh-make-perl?" Until recently I don't know that I would have been able to answer this, and I think the answer reveals a distinction that is important to keep in mind whenever you're trying to bridge between CPAN and your operating system's package manager.

Specifically, I think dh-make-perl is for maintaining a Debian package that happens to be a Perl module, and cpan2dist is for wrapping modules from CPAN in a package manager-friendly way. Let me expand on both of those:

dh-make-perl was written by Debian people, and seems aimed towards people who would like to maintain a module in full Debian style, filling in all the metadata like a changelog and description and so on.

  • It leaves you a source tree with a debian/ directory, so it's easy to take the autogenerated files and go from there on your own.
  • It lets you easily tweak an individual package's Debian package information.
  • It does not recurse into dependencies at all, it just notes them in the generated debian/control file, though I think by default it will warn and ignore any dependencies that don't have a Debian package.

If there are one or two modules you need to install that aren't in Debian -- maybe because they're internal code -- and you don't mind maintaining the Debian metadata, you probably want dh-make-perl (or to submit a request for packaging bug to the Debian Perl Group).

cpan2dist was written by Perl people, and CPANPLUS::Dist::Deb really only pays lip service to Debian's packaging conventions.

  • It assumes that modules' licenses permit redistribution, and fills the bare minimum metadata needed to install the package in many places.
  • It does recursively build debs of dependencies, and gives you some control over how to build all of those packages -- a common prefix to use in the package name, build tool options, etc.
  • It doesn't know anything about some of the weird historical decisions that have gone into Debian's perl (e.g. libcgi-perl is not but some distribution named cvswebedit), and does not (currently) give you quite enough control to make the packages it generates fit in with Debian's perl in every case.

I treat cpan2dist as a way of making it easier on my sysadmin to manage Perl modules that I would otherwise just install with the CPAN shell -- installing into /usr/local instead of /usr, for example -- and I don't try to match up with any of those historical edge cases. If you frequently need newer versions of modules than Debian provides, or if you want to install a lot of internal Perl code as debs (especially if you have an internal CPAN mirror that your code is injected into, e.g. with CPAN::Mini::Inject), or if you don't really feel like interacting with Debian's perl much at all, you probably want dh-make-perl.

(Disclaimer: I do not use dh-make-perl with any regularity, so my assessment of it may be insufficiently deep. Please correct me if I've said anything wrong.)

Long term, I'd like to be distributing my own perl package, at which point I'd be using apt-get and dpkg as a convenient distribution and management mechanism. cpan2dist is a much better fit for that goal -- I don't want to have to spend the time munging each Perl module's Debian package's control files for use with my own perl.

If you aren't using Debian, there may be something like dh-make-perl written specifically for your packaging system (I'm aware of g-cpan and g-cpanp for Gentoo, and I'd be amazed if RPM didn't have something too). cpan2dist should work the same everywhere; it has backends for Arch, Gentoo, Deb, RPM for Fedora and Mandriva, and finally PAR, which is itself cross-platform.

In every case there will probably be this same tradeoff between tighter integration with the native package manager's assumptions and ease of use for installing arbitrary CPAN modules, so be prepared to choose one or the other.

(originally posted at OpenSourcery)

Friday, May 29, 2009

Catalyst-Action-REST update

A while ago, I talked about my plans for Catalyst-Action-REST, and since then I've made some progress on refactoring to use roles instead of classes. Unfortunately, I've been stalled for the last few weeks, and I could use a nudge to get back on track.

My brain is stuck, basically, on naming issues. This feels a little silly and trivial, but it's something I've run aground on twice now, so I need to fix it somehow. The biggest problem is "serialize" -- Catalyst-Action-REST uses it both as a generic name for "things that either serialize or deserialize" and specifically for "things that serialize" (that is, "convert data to formatted text"). This means I end up wanting to use it to describe a bunch of things:

  • Serialization formats, like YAML or JSON
  • Common code shared by all serialization formats
  • Actions implementing specific serialization formats
  • The role for actions that do either serialization or deserialization
  • The specific action role that does serialization
You can see the results of this sort of naming confusion in the current code on github: Catalyst::ActionRole::SerializeFormat is a pretty goofy namespace.

In my previous post I threatened to split serialization out into its own distribution. I'm not sure how this would overlap with something like Data::Serializer, which is currently used by some of C-A-REST's serialization formats. Maybe it'd be simpler to just punt to Data::Serializer for all the serialization and deserialization, but even then I'd have to keep some class names around for backwards compatibility.


(originally posted at OpenSourcery)