How do I make a Rake Task run after all other tasks? (i.e. a Rake AfterBuild task)

Question

I'm new to Rake and using it to build .net projects. What I'm interested in is having a Summary task that prints out a summary of what has been done. I want this task to always be called, no matter what tasks rake was invoked with.

Is there an easy way to accomplish this?

Thanks

---

Update on the question, responding to Patrick's answer what I want is the after task to run once after all other tasks, so the output I want is:

task :test1 do 
  puts 'test1'
end

task :test2 do 
  puts 'test2'
end

Rake::Task.tasks.each do |t|
    <Insert rake magic here>
#  t.enhance do 
#    puts 'after'
#  end
end

$ rake test1
test1
after

$rake test2
test2
after

$rake test1 test2  
test1
test2
after

and if

task :test3 =>[:test1, :test2]
   puts 'test3'
end

    $rake test3
test1
test2
test3
after

Even though the bounty is gone, any further help much appreciated. (Sadily I don't think that I can offer another bounty.)

Answer 1

You should be able to do this with 'enhance':

Rake::Task["my_task"].enhance do
  Rake::Task["my_after_task"].invoke
end

This will cause 'my_after_task' to be invoked after 'my_task'.

If you want to apply this to all tasks, just loop over all the tasks and call enhance for each:

Rake::Task.tasks.each do |t| 
  t.enhance do 
    Rake::Task["my_after_task"].invoke
  end
end

Full test file:

task :test1 do 
  puts 'test1'
end

task :test2 do 
  puts 'test2'
end

Rake::Task.tasks.each do |t|
  t.enhance do 
    puts 'after'
  end
end

And the output:

$ rake test1
test1
after

$ rake test2
test2
after

Answer 2

Found this simple elegant answer here that uses the Ruby method at_exit.

It's worth noting that the method defined after at_exit will run every time the rake script is invoked regardless of the task run, or if any task is run. This includes when running rake -T (to list available tasks). Make sure that at_exit only does anything if a previous task told it to do so.

rakefile.rb

desc "Lovely task a"
task :a do
  puts "a"
end

desc "Lovely task b"
task :b do
  puts "b"
end

task :cleanup do
  puts "cleanup"
end

at_exit { Rake::Task[:cleanup].invoke if $!.nil? }

shell

$ rake a b
a
b
cleanup
$ rake -T
rake a # Lovely task a
rake b # Lovely task b
cleanup

You also don't need to make it run a task if you don't want to.

at_exit do
  puts "cleanup"
end

Or make it run an method

def on_exit_do_cleanup
  puts "cleanup"
end

at_exit { on_exit_do_cleanup }

And you may want to make sure you only do the cleanup if a task actually ran so that rake -T won't also do a cleanup.

rakefile.rb

do_cleanup = false

desc "Lovely task a"
task :a do
  puts "a"
  do_cleanup = true
end

desc "Lovely task b"
task :b do
  puts "b"
  do_cleanup = true
end

task :cleanup do
  return unless $!.nil? # No cleanup on error
  return unless do_cleanup # No cleanup if flag is false
  puts "cleanup"
end

at_exit { Rake::Task[:cleanup].invoke }