error using Brb in an embedded Ruby environment

[Graham Menhennitt]

I'm trying to use BrB in a Ruby script that's called from a C++ program using an embedded Ruby interpreter. The BrB script works correctly when called from the command line. However, when it's run embedded, it gives the following error:

E, [2012-11-21T11:41:58.972989 #24529] ERROR -- : /usr/local/lib/ruby/1.9.1/thread.rb:184:in `pop'
/usr/local/lib/ruby/gems/1.9.1/gems/brb-0.3.1/lib/brb/event_machine.rb:23:in `ensure_em_is_started!'
/usr/local/lib/ruby/gems/1.9.1/gems/brb-0.3.1/lib/brb/event_machine.rb:32:in `open'
/usr/local/lib/ruby/gems/1.9.1/gems/brb-0.3.1/lib/brb/tunnel.rb:13:in `create'
/gfm/EmulatorWrapper.rb:6:in `initialize'

The script is very simple:

require 'rubygems'
require 'brb'

class EmulatorWrapper
    def initialize(headerVersion)
        @emulator = BrB::Tunnel.create(nil, "brb://localhost:5555")
        @emulator.init(headerVersion)
    end
end

I call it from C++ with:

RUBY_INIT_STACK;
ruby_init();
ruby_init_loadpath();
ruby_script("EmulatorWrapper");
rb_require("./EmulatorWrapper");
VALUE headerVersion = INT2NUM(HeaderVersionNumber);
emulator = rb_class_new_instance(1, &headerVersion, rb_const_get(rb_cObject, rb_intern("EmulatorWrapper")));

I'm using Ruby 1.9.3-p327 on Linux. The BrB server is waiting for connections and calling this script from IRB works correctly.

Does anybody have any clues please?

Thanks,
  Graham

[Graham Menhennitt]

I tried turning it around and making the embedded Ruby side into the BrB server. Now I get the following error:

E, [2012-11-21T15:15:42.391016 #14406] ERROR -- : /usr/local/lib/ruby/1.9.1/thread.rb:157:in `push'
/usr/local/lib/ruby/gems/1.9.1/gems/brb-0.3.1/lib/brb/event_machine.rb:58:in `block in open_server'
/usr/local/lib/ruby/gems/1.9.1/gems/eventmachine-1.0.0/lib/eventmachine.rb:248:in `call'
/usr/local/lib/ruby/gems/1.9.1/gems/eventmachine-1.0.0/lib/eventmachine.rb:248:in `schedule'
/usr/local/lib/ruby/gems/1.9.1/gems/brb-0.3.1/lib/brb/event_machine.rb:57:in `open_server'
/usr/local/lib/ruby/gems/1.9.1/gems/brb-0.3.1/lib/brb/service.rb:26:in `start_service'
/root/TetraFlexApi/EmulatorWrapper.rb:10:in `block in initialize'
/usr/local/lib/ruby/gems/1.9.1/gems/eventmachine-1.0.0/lib/eventmachine.rb:187:in `call'
/usr/local/lib/ruby/gems/1.9.1/gems/eventmachine-1.0.0/lib/eventmachine.rb:187:in `run_machine'
/usr/local/lib/ruby/gems/1.9.1/gems/eventmachine-1.0.0/lib/eventmachine.rb:187:in `run'
/gfm/EmulatorWrapper.rb:9:in `initialize'

Graham

[Graham Menhennitt]

A bit more investigation shows that the lines 157 and 184 of thread.rb both do "@mutex.synchronize". I also added a print just before those lines to verify that @mutex was of the correct type - it was: #<Mutex:0xa0f5adc>. The error being reported is:

undefined method `synchronize' for #<Mutex:0xa0f5adc>

That's really wierd!

I narrowed it down to s simple test program:

#include <ruby.h>

int
main(int argc, char *argv[])
{
    RUBY_INIT_STACK;
    ruby_init();
    ruby_init_loadpath();

    rb_eval_string("$mutex = Mutex.new");
    rb_eval_string("$mutex.synchronize(){}");

    return 0;
}

Sure enough, this fails with the same error.

It looks like a bug in the interpreter to me. I see a few other people reporting similar things in the past. I try the ruby.core mailing list.

Graham