Presented at the YAPC::Europe 2010 conference in Pisa, Italy

1. Perl in the Real World
Jon Allen (JJ) – jj@opusvl.com
YAPC::Europe 2010
Perl in the Real World
Open Source Business Systems
www.opusvl.com

2. About OpusVL
• Open Source development company
• Based in Rugby, UK
• Founded in 2000
– Celebrated our 10th anniversary in January 2010
• Provide Open Source business systems
– National retailers, financial institutions, SMEs
– Solutions, not code
Perl in the Real World
Open Source Business Systems
www.opusvl.com

3. What do we do?
• Bespoke software development
– Back-office / financial systems
– eCommerce
– Intranet applications
• Proud to use Perl
– And Moose, Catalyst,
DBIx::Class, cpanminus,
Test::More, etc
http://xkcd.com/208/
Perl in the Real World
Open Source Business Systems
www.opusvl.com

4. Intranet project
• National chain of car dealerships (UK)
• Very large feature set
• Multiple domains
– Sales, HR, Customer Service, Finance
• Future plans
– Integrate all back-office systems
Perl in the Real World
Open Source Business Systems
www.opusvl.com

5. Architecture
• Two key design considerations:
• Entensible
– Long life-cycle, always adding new features
• Maintainable
– Modular design, develop and update individual
components independently of the whole system
Perl in the Real World
Open Source Business Systems
www.opusvl.com

6. Pluggable Catalyst apps
• Create a "base" application
– Common functions, views, models etc
– Authentication and access control
– Standard user interface components
• Write application plugins as CatalystX::
components
• Combine these together into a new Catalyst app
Perl in the Real World
Open Source Business Systems
www.opusvl.com

7. CatalystX::AppBuilder
• Programmable configuration for Catalyst
applications
– Define your application in code
– Extend in the next app, then extend again and so on
• Handles inheritance path for components
– e.g. a chain of template directories for
Catalyst::View::TT
– $self->inherited_path_to('root','templates')
Perl in the Real World
Open Source Business Systems
www.opusvl.com

8. CatalystX::InjectComponent
• Injects Controller, Model, and View components
into a Catalyst application
after 'setup_components' => sub {
my $class = shift;
CatalystX::InjectComponent->inject(
into => $class,
component => 'My::Other::Controller::JJ',
as => 'Controller::NewName',
);
}
• Create components with CatalystX::Starter
Perl in the Real World
Open Source Business Systems
www.opusvl.com

9. Deployment
• Base OS – typically Debian
• Three environments
– Development
– Staging
– Production
• Always compile Perl from source
– System Perl belongs to the OS, custom Perl 5.10.1
for applications
Perl in the Real World
Open Source Business Systems
www.opusvl.com

10. First rule of Installation Club
• Everything installed to Staging and Production
must be packaged as CPAN-style modules
– Standard module layout
– Makefile.PL, t/*, Pod documentation
– All modules are versioned
• Very simple to regress to a previous release
• Perl is the OS
– Unlike native OS packages, CPAN works on Debian,
RHEL, Mac OS X, Solaris, etc
Perl in the Real World
Open Source Business Systems
www.opusvl.com

11. Use the toolchain, Luke
• Install using cpanminus
– Resolves dependencies
– Very fast
– Standard install procedure for each project
– cpanm --sudo --installdeps .
• Components of a large system can be managed
and upgraded independently
Perl in the Real World
Open Source Business Systems
www.opusvl.com

12. Future
• Internal CPAN mirror
– Include all custom code
– Task:: modules to set up client environments
• Internal Perldoc
– Develop on top of Perldoc::Server
• Don't fight it, feel it
– CPAN toolchain gives many benefits
– Well worth using!
Perl in the Real World
Open Source Business Systems
www.opusvl.com

13. Conclusion
• Clients care about results, not code
– The technology is our job
• Perl gives us the tools to deliver
• The Perl Community makes it possible
• Thank you!
Perl in the Real World
Open Source Business Systems
www.opusvl.com