How to pass different arguments in rake multitask

Question

I want to pass different arguments to every method and need to run all methods parallel using rake task

Here is rake task calling example

Rake::Task['test:sync'].invoke(user.id, user.address)
Rake::Task['test:sync'].invoke(user.id, user.address)
Rake::Task['test:sync'].invoke(user.id, user.address)

I have seen the multitask example like this

multitask :copy_files => [:copy_src, :copy_doc, :copy_bin] do
    puts "All Copies Complete"
end

Here they are calling with the task name alone. But in my case i want to pass task name with parameters . How can i achieve it.

Answer 1

Extract the functionality into its own method (foo) and dynamically declare rake tasks with the arguments (arg1,arg2) baked into the task name itself. Then declare a multitask and invoke it. All calls to foo will be run in parallel.

def foo(arg1, arg2)
  thread_id = Thread.current.object_id.to_s[-4..-1]
  10.times do |i|
    sleep rand
    puts "[#{thread_id}] (#{arg1}) (#{arg2}) (#{i})"
  end
end

task :parallel_foos do
  arg1s = (1..4).map { sprintf('%.4f', rand) }
  arg2s = %w{red green blue yellow}
  arg_pairs = arg1s.zip(arg2s)
  # dynamically declare unique rake tasks
  arg_pairs.each do |arg_pair|
    task arg_pair.to_s do
      foo(*arg_pair)
    end
  end
  multitask :_parallel_foos => arg_pairs.map(&:to_s)
  Rake::MultiTask[:_parallel_foos].invoke
end

>> rake parallel_foos
[2460] (0.4510) (blue) (0)
[4820] (0.5997) (yellow) (0)
[4820] (0.5997) (yellow) (1)
[2980] (0.3482) (red) (0)
[2980] (0.3482) (red) (1)
[2100] (0.2251) (green) (0)
[2980] (0.3482) (red) (2)
[4820] (0.5997) (yellow) (2)
[2460] (0.4510) (blue) (1)
[2980] (0.3482) (red) (3)
[4820] (0.5997) (yellow) (3)
[2100] (0.2251) (green) (1)
[2980] (0.3482) (red) (4)
[2100] (0.2251) (green) (2)
[2460] (0.4510) (blue) (2)
[2100] (0.2251) (green) (3)
[4820] (0.5997) (yellow) (4)
[2460] (0.4510) (blue) (3)
[2980] (0.3482) (red) (5)
[4820] (0.5997) (yellow) (5)
[2460] (0.4510) (blue) (4)
[2980] (0.3482) (red) (6)
[2100] (0.2251) (green) (4)
[2460] (0.4510) (blue) (5)
[4820] (0.5997) (yellow) (6)
[2100] (0.2251) (green) (5)
[2980] (0.3482) (red) (7)
[2460] (0.4510) (blue) (6)
[4820] (0.5997) (yellow) (7)
[2980] (0.3482) (red) (8)
[2100] (0.2251) (green) (6)
[4820] (0.5997) (yellow) (8)
[2460] (0.4510) (blue) (7)
[2100] (0.2251) (green) (7)
[2980] (0.3482) (red) (9)
[2460] (0.4510) (blue) (8)
[4820] (0.5997) (yellow) (9)
[2460] (0.4510) (blue) (9)
[2100] (0.2251) (green) (8)
[2100] (0.2251) (green) (9)