module ActiveJob::Execution

def _perform_job 

def _perform_job
  ActiveSupport::ExecutionContext[:job] = self
  run_callbacks :perform do
    perform(*arguments)
  end
end

def perform(*) 

def perform(*)
  fail NotImplementedError
end

def perform_now

puts MyJob.new(*args).perform_now # => "Hello World!"

end
end
"Hello World!"
def perform
class MyJob < ActiveJob::Base

+perform_now+ returns the value of your job's +perform+ method.
but directly executed by blocking the execution of others until it's finished.
Performs the job immediately. The job is not sent to the queuing adapter 
def perform_now
  # Guard against jobs that were persisted before we started counting executions by zeroing out nil counters
  self.executions = (executions || 0) + 1
  deserialize_arguments_if_needed
  _perform_job
rescue Exception => exception
  rescue_with_handler(exception) || raise
end