How can I use spoon to execute a ruby block like fork does?

[ramarnat]

I am looking to update some code that uses fork so it's compatible with JRuby. The code runs a fork with a block of code, how do I accomplish the same functionality with spoon? I think I have to kick off another jruby instance, but how do I have it hone in on running a particular block?

This is from the aws simple workflow sdk btw.

 class ForkingExecutor 
     def execute(&block)
        @log.error "Here are the pids that are currently running #{@pids}"
        raise RejectedExecutionException if @is_shutdown
        block_on_max_workers
        @log.debug "PARENT BEFORE FORK #{Process.pid}"
        child_pid = fork do
          begin
            @log.debug "CHILD #{Process.pid}"
            # TODO: which signals to ignore?
            # ignore signals in the child
            %w{ TERM INT HUP SIGUSR2 }.each { |signal| Signal.trap(signal, 'SIG_IGN') }
            block.call
            @log.debug "CHILD #{Process.pid} AFTER block.call"
            Process.exit!(0)
          rescue => e
            @log.error e
            @log.error "Definitely dying off right here"
            Process.exit!(1)
          end
        end
        @log.debug "PARENT AFTER FORK #{Process.pid}, child_pid=#{child_pid}"
        @pids << child_pid
      end
end

worker = WorkflowWorker.new(@swf.client, @domain, task_list)
forking_executor = ForkingExecutor.new
forking_executor.execute { worker.start }

[headius]

There's no way to spawn a subprocess using a block of code under JRuby, even with the spoon gem. However, it should be simple to replace this code with a thread that runs the logic and then terminates itself. You'd get the same concurrency without spawning.

[ramarnat]

thanks for the quick reply!

the workers need to run as separate processes, so I think I will follow the pattern laid out by foreman by using a runner as laid out here - https://github.com/ddollar/foreman/pull/140

[ramarnat]

Looking down another path, I found your gist https://gist.github.com/headius/1378616

But it doesn't work in 1.7.4, expected?

[ramarnat]

got further by using java.util.concurrent.ThreadPoolExecutor as you suggested, but now looks like I hit a wall with this JRuby bug - http://jira.codehaus.org/browse/JRUBY-7188

giving up and going back to MRI for now :(