Creating a controller in Catalyst

A new controller in Catalyst is registered by running script/APPNAME_create.pl CONTROLLER_NAME. This creates a module in the controller directory and a test in the test directory. These are apparently all that is needed for a controller to be created.

It's worth noting that /foo can activate either App::Controller::Foo::index() or App::Controller::Root::foo(). However, if both exist, App::Controller::Foo::index() takes precedence.

Module Monday: Quantum::Superpositions

A new weekly feature. I'm going to dig out some of the hidden gems of CPAN. One of the best places to look is Damian Conway's list of modules and this is one fun and interesting one.

Here's a selection of what Quantum::Superpositions can do:

$wanted = any("Mr","Ms").any(@names);
if ($name eq $wanted) { print "Reward!"; } 

$okay = all(\&check1,\&check2);
die unless $okay->();

my $large =
         all(    BigNum->new($centillion),
                   BigNum->new($googol),
                   BigNum->new($SkewesNum)
          );
@huge =  grep {$_ > $large} @nums;

Installing Rose::DB::Object

For the Backlog project, I was thinking this was going to be a good opportunity to also learn Rose::DB::Object, so I tried installing it via CPAN. Oops, it had some errors along the way. It turns out that SQL::ReservedWords has a dependency on Data::OptList which it doesn't declare. Installing Data::OptList solved that problem, but Rose::DB::Object is still failing its test suite:

t/db-object-manager..................7/3900 Can't locate object method "format_select_start_sql" via package "Rose::DB::__RoseDBPrivate__::Rose::DB::MySQL" at /Users/dhosek/.cpan/build/Rose-DB-Object-0.769-AXgKMz/blib/lib/Rose/DB/Object/QueryBuilder.pm line 725.
# Looks like you planned 3900 tests but only ran 827.
# Looks like your test died just after 827.
t/db-object-manager.................. Dubious, test returned 255 (wstat 65280, 0xff00)
 Failed 3073/3900 subtests 
 (less 783 skipped subtests: 44 okay)

My insomnia feels resolved, so I'll come back to this after sleep.

Update (21 April): I managed to solve the problem: Doing an install of Rose::DB::MySQL then re-trying to install Rose::DB::Object managed to do the trick.

Learning Catalyst: The Backlog project. Day 1

The Plan

What I'm looking to build is a web application which is designed for maintaining a product backlog. I see the following as the key user stories:

• As a programmer, I want the system to use the wiki as its primary display and authentication system (so, users will log into Backlog using their wiki credentials, and the backlog is visible from the wiki).
• As a programmer, I want the system to import the existing backlog from the wiki.
• As a User, I want to be able to submit stories to the product backlog.
• As a product owner, I want to be able to prioritize and arrange the backlog.

Installing Catalyst

This went far more easily than I expected. A simple CPAN install brought it in with no problems. I guess I was just lucky on that front.

Building the core

Step one was to build the core of the application. I ran catalyst.pl from the command line and got the following:

~/dev/Backlog> catalyst.pl Backlog
To use the Catalyst development tools including catalyst.pl and the
generated script/myapp_create.pl you need Catalyst::Helper, which is
part of the Catalyst-Devel distribution. Please install this via a
vendor package or by running one of -

  perl -MCPAN -e 'install Catalyst::Devel'
  perl -MCPANPLUS -e 'install Catalyst::Devel'

Apparently the Catalyst package is divided into two parts, one just for running Catalyst, one for developing Catalyst applications. Fortunately this install was also uneventful.

Rerunning it, I got

~/dev/Backlog> catalyst.pl Backlog
created "Backlog"
created "Backlog/script"
created "Backlog/lib"
created "Backlog/root"
created "Backlog/root/static"
created "Backlog/root/static/images"
created "Backlog/t"
created "Backlog/lib/Backlog"
created "Backlog/lib/Backlog/Model"
created "Backlog/lib/Backlog/View"
created "Backlog/lib/Backlog/Controller"
created "Backlog/backlog.yml"
created "Backlog/lib/Backlog.pm"
created "Backlog/lib/Backlog/Controller/Root.pm"
created "Backlog/README"
created "Backlog/Changes"
created "Backlog/t/01app.t"
created "Backlog/t/02pod.t"
created "Backlog/t/03podcoverage.t"
created "Backlog/root/static/images/catalyst_logo.png"
created "Backlog/root/static/images/btn_120x50_built.png"
created "Backlog/root/static/images/btn_120x50_built_shadow.png"
created "Backlog/root/static/images/btn_120x50_powered.png"
created "Backlog/root/static/images/btn_120x50_powered_shadow.png"
created "Backlog/root/static/images/btn_88x31_built.png"
created "Backlog/root/static/images/btn_88x31_built_shadow.png"
created "Backlog/root/static/images/btn_88x31_powered.png"
created "Backlog/root/static/images/btn_88x31_powered_shadow.png"
created "Backlog/root/favicon.ico"
created "Backlog/Makefile.PL"
created "Backlog/script/backlog_cgi.pl"
created "Backlog/script/backlog_fastcgi.pl"
created "Backlog/script/backlog_server.pl"
created "Backlog/script/backlog_test.pl"
created "Backlog/script/backlog_create.pl"

running ./Backlog/script/backlog_server.pl started up the web server on port 3000 and I was able to verify that I had a working Catalyst application to begin playing with.

The @INC array can be more dynamic than you think

We can put subroutine references, array references and objects into the @INC array. See perldoc -f require for the hairy details.

Test-first doesn't mean every test must be written before you start coding

It's worth noting that test-first doesn't mean that all the tests have to be written before any code is written. In fact, in some cases, it's actually impossible to write the test before the implementation is at least partly scoped out (e.g., when it's necessary to mock objects or modules external to what you're testing). A lot of test cases end up coming up during the development process. Just like elsewhere in agile development, the secret is in tight loops. Write the test as soon as possible, but no sooner than necessary.

Installing DBD::mysql on OS X Leopard 10.5.2

One of those minor nightmare installs. I need this though, so I've gotta work for a while.

Here is the problem that shows up:

~/.cpan/build/DBD-mysql-4.006-j5Hpiv> prove -v -l t/00base.t
t/00base......
1..5
ok 1
ok 2
ok 3
install_driver(mysql) failed: Can't locate loadable object for module DBD::mysql in @INC (@INC contains: /Users/dhosek/.cpan/build/DBD-mysql-4.006-j5Hpiv/lib /Users/dhosek/.cpan/build/DBD-mysql-4.006-j5Hpiv/lib /System/Library/Perl/5.8.8/darwin-thread-multi-2level /System/Library/Perl/5.8.8 /Library/Perl/5.8.8/darwin-thread-multi-2level /Library/Perl/5.8.8 /Library/Perl /Network/Library/Perl/5.8.8/darwin-thread-multi-2level /Network/Library/Perl/5.8.8 /Network/Library/Perl /System/Library/Perl/Extras/5.8.8/darwin-thread-multi-2level /System/Library/Perl/Extras/5.8.8 /Library/Perl/5.8.6 /Library/Perl/5.8.1 .) at (eval 3) line 3
Compilation failed in require at (eval 3) line 3.
Perhaps a module that DBD::mysql requires hasn't been fully installed
 at t/00base.t line 38
 Dubious, test returned 2 (wstat 512, 0x200)
 Failed 2/5 subtests 

Test Summary Report
-------------------
t/00base.t (Wstat: 512 Tests: 3 Failed: 0)
  Non-zero exit status: 2
  Parse errors: Bad plan.  You planned 5 tests but ran 3.

First step, is that I'm finding that the blib/arch/auto/DBD/mysql/mysql.so file is not being created.

Actually, that's not the problem! Looking closer, I'm seeing that the .bs and .bundle files are apparently the ones that apply now. Interestingly using prove -b t/00base.t does in fact work. But make test has the same test fail...

Ignoring that issue, I move on to the next test:

prove -b t/10connect.t 
t/10connect......dyld: lazy symbol binding failed: Symbol not found: _mysql_server_init
  Referenced from: /Users/dhosek/.cpan/build/DBD-mysql-4.006-j5Hpiv/blib/arch/auto/DBD/mysql/mysql.bundle
  Expected in: dynamic lookup

dyld: Symbol not found: _mysql_server_init
  Referenced from: /Users/dhosek/.cpan/build/DBD-mysql-4.006-j5Hpiv/blib/arch/auto/DBD/mysql/mysql.bundle
  Expected in: dynamic lookup

t/10connect...... Failed 2/2 subtests 

Test Summary Report
-------------------
t/10connect.t (Wstat: 5 Tests: 0 Failed: 0)
  Parse errors: Bad plan.  You planned 2 tests but ran 0.
Files=1, Tests=0,  0 wallclock secs ( 0.01 usr  0.00 sys +  0.04 cusr  0.00 csys =  0.05 CPU)
Result: FAIL

Update: 11 April 2008 The problem has its roots in using the pre-compiled distribution of mysql from mysql.com rather than building from source. This resulted in getting incompatible libraries between what was compiled for DBD::mysql and what I had in the mysql directory. Building from source resolved the problem. Good instructions on doing the job are available at HiveLogic.

Getting Things Done

I first became aware of Getting Things Done from the 43 folders web site. While I've had the book for a couple years, I finally read it this week (along with installing OmniFocus on my work Mac). So far, I'm finding the GTD workflow to be quite helpful. Omnifocus, somewhat less so, other than as a trusted repository for projects. The big difficulty is that Omnifocus ties me too much to the Mac. On the other hand, there has been an announcement that OmniGroup will be doing an iPhone version of Omnifocus. That plus multi-computer syncing could make Omnifocus a really great product for my needs.

First experiences with OS X Leopard (10.5)

I've finally got the iMac with Leopard on my desk at work. So far it's pretty good, although I do have a few complaints, most notably spaces got a few things wrong: cmd-tab and cmd-` should never change spaces. It's really disconcerting to have that happen. I want to be able to pretend that what's in the current workspace is everything I've got, so I can do quick and easy context switches.

And the choices for the switch between spaces are really disappointing. I don't think that I have an app which doesn't use one of ctrl-arrow, opt-arrow or cmd-arrow for something. At this point, I've just disabled the arrow switching.

Version control and databases

We have a practice of having a branch for each story in the sprint. This works fine with most stories, but what happens when we have stories that affect the database. I found this discussion on the topic which has some interesting reflections and comments. In general, though, my sense is that version control for databases is at best ad hoc and kludgy. RIght now we're doing something similar to Rails migrations, but handled manually. I'd like to formalize that process. I'm looking at DBIx::Migration::Directories, although I find no commentary on it at all, anywhere.