How I want Ganymede to work:

# app/workers/foo_bar_worker.rb
class FooBarWorker < Ganymede::Worker

  def foo(options)

  end

  def bar(options)

  end

end

# somewhere that jobs are dispatched

def do_a_thing(because)
  @because = because
  FooBarWorker.foo(self)
end

def to_ganymede
  { 
    :id => id,
    :class => self.class.name,
    :event_name => self.event.name,
    :size => estimate_job_size,
    :trigger => @because
  }
end

# config/initializers/ganymede.rb

# Default configuration: all workers listen to all jobs, one thread per job,
# no filtering.
Ganymede.configure do |config|
  config.layout do |layout|
    # layout.no_default_node! if you do not want a default node type
    layout.node :bigjobs do |bigjobs|
      bigjobs.worker :FooBarWorker, :only => { :size => "big" }, :threads => 2
      bigjobs.worker :FooBarWorker, :only => { :size => "big", :trigger => "scheduled" }, :threads => 1
    end
    layout.default.worker :FooBarWorker, :only => { :size => "small", :trigger => "scheduled" }, :threads => 2
    layout.default.worker :FooBarWorker, :only => { :size => "small", :trigger => "on-demand" }, :threads => 4
    layout.default.worker :FooBarWorker, :only => { :size => "small", :trigger => "requested" }, :threads => 1
  end
  # config.middleware_out << Ganymede::Middleware::AutoSplatObjects
end

class Ganymede::Middleware::AutoSplatObjects

  def call(*opts)
    if opts.length == 1 and !opts.first.kind_of?(Hash)
      if opts.respond_to?(:to_ganymede)
        opts = opts.to_ganymede
      end
    end
    yield opts
  end

end

# equivalent to:
layout = Ganymede::Layout.new
default = Ganymede::Layout::Node.new(:default)
default.default_configuration!
default.add_worker Ganymede::Layout::Worker.new(:FooBarWorker, :foo, :only => { :size => "small", :trigger => "scheduled" }, :threads => 2)
# ...
layout.add_node default
bigjobs = Ganymede::Layout::Node.new(:bigjobs)
bigjobs.add_worker Ganymede::Layout::Worker.new(:FooBarWorker, :foo, :only => { :size => "big", :trigger => "scheduled" }, :threads => 1)

server = Ganymede::Server.new(layout, :default)
server.start # FIAT LUX

# ... later ...
# ... We really need a special worker just allocated for HugeEvent

default.add_worker Ganymede::Worker.new(:FooBarWorker, :foo, :only => { :event_name => "HugeEvent" }, :threads => 1

# Loads the new layout and starts up new workers as required
server.layout = layout
server.reload