Saturday, April 05, 2008

Pragmatic Rake tasks organization

Do you have a lot of rake tasks on your Rails projects? I am sure you do. Rake tasks are handy, and developing your next-big-idea Rails app is a lot less attractive without it. Most of the time you drop a new foo.rake file in your lib/tasks folder, and you write code in it and get out. Over the course of development, that folder is likely to look like your favorite Halloween party house (ahem, Neal's...), except on an every day basis.

If you want your rake tasks to be more manageable, here are a few tips:

1) Namespace your rake tasks.

Namespaces in rake is nice. They make sure all tasks in your namespace are cohesive as a area of work. Still, your job is to keep your rake tasks not too crowded in a single namespace. For example, the db namespace that Rails provides very easily become crowded with tasks of all sorts, because, well, on a Rails application what you do almost always is related to your database: drop/create/migrate your database, importing reference/application data, database integration points with other applications, db related background tasks, backups... Phew! How about create a new namespace for import, integration, background, and backup for each of them?

2) Name your rake files by their namespaces.

Even if you namespace all your rake tasks, still, you are likely to end up with a bunch of .rake files in lib/tasks. But, now that you have your tasks grouped by their meaningful and not-so-crowded namespaces, you should name your files by your namespace. For example, db.rake, data.rake, import.rake, integration.rake, and backup.rake. Can you guess where that rake db:awesome is implemented? You certainly don't know what it does, but you got that right, in lib/tasks/db.rake.

3) Try not to nest more than 2 namespaces.

This tip is not a rule, the point being don't over do it. Sometimes, that third-level namespace really makes sense, For example, db:create:all from Rails creates databases for all environments. It isn't for everything, though. For example, I prefer rake data:load better than rake db:data:load. Not only is it shorter, but also the namespace db is simply implied. Short nested-ness forces you to name your namespaces more descriptively, and thus easier to navigate to their implementation.

4) Move your rake file and its external ruby files into a sub-folder, named by that namespace.

When your rake tasks are complicated enough, you obviously will use objects to do the job for you. When that happens, instead of having lib/tasks/integration.rake, you will instead want to have a sub-folder lib/tasks/integration/, and put files like integration.rake and integration_awesome_klass.rb in it. There really is no need to contaminate your lib folder with rake specific files.

Shameless Plug: Still using NAnt? Check out how to organize your NAnt scripts as well, on this blog post.

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