This is a plugin for the Axon socket module. It create a mode where req/rep sockets will send the next request to the least busy node instead of always using round robin.
var axon = require('axon');
var axonPriority = require('axon-priority');
var req = axon.socket('req');
axonPriority.patchSocket(req);
// continue to use the socket as you normally would...
make test
They take about 30s to a minute to run, so be patient.