Rake delete files task - ruby

Question

In msbuild I can delete part of files in certain directory like this
<ItemGroup>
<FilesToDelete Include="$(DeploymentDir)\**\*" exclude="$(DeploymentDir)\**\*.log"/>
</ItemGroup>
<Delete Files="#(FilesToDelete)" />
It will delete all files except *.txt
Is there some rake task I can similar thing?

Answer 1

Ruby has built in classes to make this easy:
Dir['deployment_dir/**/*'].delete_if { |f| f.end_with?('.txt') }
However, for some built in tasks, rake has helpers for this. Adapted from the API docs you can select files like so:
files_to_delete = FileList.new('deployment_dir/**/*') do |fl|
fl.exclude('*.txt')
end
Then you can feed this into your delete task.
Better yet, you can use the built in CLEAN/CLOBBER tasks:
# Your rake file:
require 'rake/clean'
# [] is alias for .new(), and we can chain .exclude
CLEAN = FileList['deployment_dir/**/*'].exclude('*.txt')
Then you can say on the cmd line:
rake clean
Read up the tutorial.

Answer 2

#adzdavies's answer is good, but assigning to CLEAN will produce the following warning since CLEAN is a constant:
warning: already initialized constant CLEAN
You should instead use CLEAN's instance methods. It is a Rake::FileList, so you can add something like this to your Rakefile:
require 'rake/clean'
# this is untested, but you get the idea
CLEAN.include('deployment_dir/**/*').exclude('*.txt')
Then run:
rake clean