include Opscode::Aws::Ec2

action :register do
  converge_by("add the node #{new_resource.name} to ELB") do
    target_lb = elb.describe_load_balancers.find {|lb| lb[:load_balancer_name] == new_resource.name }
    unless target_lb[:instances].include?(instance_id)
      Chef::Log.info("Adding node to ELB #{new_resource.name}")
      elb.register_instances_with_load_balancer(new_resource.name, instance_id)
    else
      Chef::Log.debug("Node #{instance_id} is already present in ELB instances, no action required.")
    end
  end
end

action :deregister do
  converge_by("remove the node #{new_resource.name} from ELB") do
    target_lb = elb.describe_load_balancers.find {|lb| lb[:load_balancer_name] == new_resource.name }
    if target_lb[:instances].include?(instance_id)
      Chef::Log.info("Removing node from ELB #{new_resource.name}")
      elb.deregister_instances_with_load_balancer(new_resource.name, instance_id)
    else
      Chef::Log.debug("Node #{instance_id} is not present in ELB instances, no action required.")
    end
  end
end

private

def elb
  region = instance_availability_zone
  region = region[0, region.length-1]
  @@elb ||= RightAws::ElbInterface.new(new_resource.aws_access_key, new_resource.aws_secret_access_key, { :logger => Chef::Log, :region => region })
end