Chicago.PM Report - App::Services by Sean Blanton

This month's technical presentation at Chicago Perl Mongers was about Sean Blanton's project called App::Services. It's an interesting project that uses Bread::Board to access resources like databases, logging, ssh, and others.

Along the way, we discussed logging practices (most of us are using Log::Log4perl), and the best way to get a Perl module ready for CPAN (I suggested using Module::Build directly, but Dist::Zilla outvoted me).

Sean mentioned in passing the Salt stack for executing commands across multiple machines, which looks like a very interesting alternative to more detailed tools like Puppet or Chef. Salt seems to be just a simple way to execute commands on multiple machines. Those commands could be administrative (restart httpd), or they could be the application.

One other very interesting thing from App::Services was providing a role for the larger system to use. So one creates App::Service::Log::Log4perl and App::Service::Log::Role, and in other services you consume the App::Service::Log::Role and then can use the Log4perl service. What's interesting about this is that the role is provided alongside the logging service, it isn't something that you have to create yourself. Doing it this way improves interoperability and simplifies adoption by giving you the tedious bits already. It's the difference between "Here's a service, figure out how to use it best" and "Here's a service, and here's a good way to use it" (I've been doing something similar by providing Test::MockObject implementations of my modules for testing purposes in the same distribution as the module itself. An "official" mock object).

In two weeks we have another project night, which I'm hoping is as productive as the last. If you're in the Chicago area, check us out on the Chicago Perl Mongers meetup page.