[Catalyst] Running Catalyst App from Command Line (or via Cron)

I always liked the solution used by Drupal of simply making cron use
curl/wget/... to request a special URL. Then it becomes an action and is
easy to code and configure almost on any platform.

Long-running tasks (beyond that of an HTTP request) are a different
matter. At present, we do this with our own task manager, which is
basically nothing to do with Catalyst -- although it shares the code
under the Catalyst model components. This creates the data needed by the
app. This can take as long as it likes. We then have a quick switch,
which updates the config and prods the web server to recycle its worker
processes.

It probably depends if you are adding data more or less monotonically to
the current app, or more radically changing it. If it is a radical
change to the data, I'd guess you'd need to close everything down
cleanly and restart.

All the best
Stuart


Christoph Friedrich wrote:

If the script is running independent of catalyst (cron job) why does it
need to involve your application. Assuming you are using DBIx::Class,
you can use your Schema and associated Result[Set] classes or even your
true domain objects (those are separate from your app right?) to
accomplish this without shoe horning in catalyst.

It is a very common requirement, and has a simple solution.

First of all, assuming you are using something like DBIx::Class as your
database backend you should write your database access layer totally
separate from Catalyst, then use Catalyst::Model::DBIC::Schema to
connect your Model in Catalyst to your database layer.

Then you can write your cron job as a perl module that just uses your
DBIx::Class directly without the complication of Catalyst.

If you are not using DBIx::Class then you can still write your model as
a separate module and create a very thin shim in your Catalyst model
using Catalyst::Model::Adaptor.

This also makes testing your Models so much easier since your tests do
not depend upon Catalyst running.
I have seen recommendations to organise your directories as follows but
I know other people have other ideas.

lib/MyApp
lib/MyApp/DB.pm - your DBIx::Class database

lib/MyApp/Web.pm - your Catalyst App
lib/MyApp/Web/Model/DB.pm - your 'thin shim' to your MyApp::DB module
lib/MyApp/Web/View
lib/MyApp/Web/Controller

Regards
Ian

I would create a standalone perl class that does everything you need,
then in your Catalyst app just implement a thin adapter using
something like Catalyst::Model::Adapter (or
Catalyst::Component::InstancePerContext).

I wouldn't bother with Catalyst in the crontab, instead just
instantiate this model and have it do what needs done.

-J