Prepend to existing rake task

Question

Defining an existing rake task again appends to the original, but I'd like to prepend to the db:migrate task. I want to raise an error beforehand in some cases. Is there a good way to prepend to an existing rake task?

Answer 1

Try adding a db:custom task on 'db' namespace and invoke db:migrate with enhance method

# add your custom code on db:custom 
namespace 'db' do
  task 'custom' do
    puts "do custom db stuff"
  end
end

# invoke db:migrate 
Rake::Task['db:migrate'].enhance [:custom]

Answer 2

Might be better to define your own task and call db:migrate inside.

namespace :custom_db do
  desc 'migrate db if condition true'
  task :migrate do
    if true #your condition
      Rake::Task['db:migrate'].invoke
    else
      #process errors
    end
  end
end