fix: workaround for zeromq connection bug

Author: coolaj86

lib/services/dashd.js

@@ -802,12 +802,26 @@ Dash.prototype._initZmqSubSocket = function(node, zmqUrl) {
   var self = this;
   node.zmqSubSocket = zmq.socket('sub');
 
+  log.info(`ZMQ opening socket to '${zmqUrl}'`);
+
+  // workaround for https://github.com/zeromq/zeromq.js/issues/574
+  var tcpTimeout = 5 * 1000;
+  var timeout = setTimeout(function () {
+    // neither accepting nor rejecting - either invalid or firewalled (DROP)
+    log.error(`ZMQ address '${zmqUrl}' cannot be reached`);
+    process.exit(1);
+  }, tcpTimeout);
+
   node.zmqSubSocket.on('connect', function(fd, endPoint) {
     log.info('ZMQ connected to:', endPoint);
+    clearTimeout(timeout);
+    timeout = null;
   });
 
   node.zmqSubSocket.on('connect_delay', function(fd, endPoint) {
     log.warn('ZMQ connection delay:', endPoint);
+    clearTimeout(timeout);
+    timeout = null;
   });
 
   node.zmqSubSocket.on('disconnect', function(fd, endPoint) {