Where are rake tasks defined?

On a freshly created Rails project (gen开发者_StackOverflowerated by rails someName), one can run some 'default' rake tasks like:

• rake test
• rake db:migrate
• etc

Question is, where does these tasks get described? The default Rakefile doesn't have all these tasks.

Furthermore, I checked out some project that uses rspec and I am able to run rake spec to run all the tests. Where does the spec target defined?

If by described you mean defined, rake -W is your friend. Example:

$ rake -W db:create

=>

rake db:create  /path/to/ruby/gems/1.9.1/gems/activerecord-3.1.11/lib/active_record/railties/databases.rake:39:in `block in <top (required)>'

Just found this out today :)

Rake tasks are automatically loaded from the folder structure lib/tasks/*.rake

When we are talking about the task db:migrate for example, it is located within the rails gem in lib/tasks/databases.rake

So for a specific project, you will always have the tasks within the project folder structure as well as all tasks within the specified gems.

To find the specific files and line numbers where a task is defined and/or modified, do this:

Start a rails console:

rails c

Then run these commands:

require 'rake'
Rake::TaskManager.record_task_metadata=true
Rake.application.load_rakefile
tsk = Rake.application.tasks.find {|t| t.name =='my_task_name'}
tsk.locations

Rake basically can track the locations internally and has a nifty method to show them upon request. The above code basically loads rake, tells Rake to track the file locations, loads the Rakefile (and all other included ones), finds the task in question, and calls the locations method on it.

From sameers comment, for rake v 10.1.0 and possibly older versions of rake you might have to call: tsk.actions instead of tsk.locations

You didn't specify which version of rails you're using but in 3.0.7 the db tasks are located in the ActiveRecord gem in

lib/active_record/railties/databases.rake

Update:

As of rails version 3.2.7, the tasks are still where I stated above.

In Rails 3 the railties gem defines a lot of rake tasks.

railties-3.2.5/lib/rails/tasks/annotations.rake
railties-3.2.5/lib/rails/tasks/documentation.rake
railties-3.2.5/lib/rails/tasks/engine.rake
railties-3.2.5/lib/rails/tasks/framework.rake
railties-3.2.5/lib/rails/tasks/log.rake
railties-3.2.5/lib/rails/tasks/middleware.rake
railties-3.2.5/lib/rails/tasks/misc.rake
railties-3.2.5/lib/rails/tasks/routes.rake
railties-3.2.5/lib/rails/tasks/statistics.rake
railties-3.2.5/lib/rails/tasks/tmp.rake
railties-3.2.5/lib/rails/test_unit/testing.rake

If your $EDITOR is configured, you can easily see them yourself with the open_gem gem:

gem install open_gem
gem open railties

To list all tasks:

rake -P

Since many tasks come from gems you install it's hard to know which ones are added...

The project you checked out probably uses the rspec-rails gem. That gem defines the spec task. You can see the source code for it here:

https://github.com/rspec/rspec-rails/blob/master/lib/rspec/rails/tasks/rspec.rake