module S3Website
  class Parallelism
    def self.each_in_parallel_or_sequentially(items, &operation)
      if ENV['disable_parallel_processing']
        items.each do |item|
          operation.call item
        end
      else
        threads = items.map do |item|
          Thread.new(item) { |item|
            operation.call item
          }
        end
        threads.each { |thread| thread.join }
      end
    end
  end
end