MetricsWeb.java

public class MetricsWeb extends BaseTaskHook {
    private static final Logger log = LoggerFactory.getLogger(MetricsWeb.class);
    private static Server server = null;
    private static CuratorFramework zk = null;
    private static ServiceDiscovery<Void> dsc = null;

    @Override
    public void prepare(Map conf, TopologyContext context) {
        if ("production".equals(conf.get("environment"))) {
            initWebConsole(9090);
        }
    }

    @Override
    public void cleanup() {
        destroyWebConsole();
    }

    private synchronized int initWebConsole(int port) {
        if (server == null) {
            log.info("Attempting to start server on {}...", port);
            server = new Server(port);
            Context context = new Context(server, "/");

            context.addServlet(HystrixMetricsStreamServlet.class, "/hystrix.stream");
            context.addServlet(DebugServlet.class, "/debug");

            try {
                server.start();

                log.info("Started server on {}...", port);

                return port;
            } catch (BindException e) {
                server = null;
                return initWebConsole(port+1);
            } catch (Exception e) {
                e.printStackTrace();
                return -1;
            }
        }

        return -1;
    }

    private synchronized void destroyWebConsole() {
        if (server == null) return;

        try {
            server.stop();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

TopologySetup.java

stormConfig.put(Config.TOPOLOGY_AUTO_TASK_HOOKS, Lists.newArrayList(MetricsWeb.class.getName()));