From 531da092277f08b050fc943ea2134c966ef2970d Mon Sep 17 00:00:00 2001
From: Martin Boehm <martin.boehm@1mbsoftware.net>
Date: Fri, 23 Feb 2018 11:56:44 +0100
Subject: [PATCH] Improve ZeroMQ startup/shutdown

---
 bchain/mq.go | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/bchain/mq.go b/bchain/mq.go
index bd6f03bb..f9a21c4a 100644
--- a/bchain/mq.go
+++ b/bchain/mq.go
@@ -33,13 +33,22 @@ func NewMQ(binding string, callback func(*MQMessage)) (*MQ, error) {
 	if err != nil {
 		return nil, err
 	}
-	socket.SetSubscribe("hashblock")
-	socket.SetSubscribe("hashtx")
+	err = socket.SetSubscribe("hashblock")
+	if err != nil {
+		return nil, err
+	}
+	err = socket.SetSubscribe("hashtx")
+	if err != nil {
+		return nil, err
+	}
 	// for now do not use raw subscriptions - we would have to handle skipped/lost notifications from zeromq
 	// on each notification we do sync or syncmempool respectively
 	// socket.SetSubscribe("rawblock")
 	// socket.SetSubscribe("rawtx")
-	socket.Connect(binding)
+	err = socket.Connect(binding)
+	if err != nil {
+		return nil, err
+	}
 	glog.Info("MQ listening to ", binding)
 	mq := &MQ{context, socket, true, make(chan bool)}
 	go mq.run(callback)
@@ -78,6 +87,8 @@ func (mq *MQ) run(callback func(*MQMessage)) {
 func (mq *MQ) Shutdown() error {
 	glog.Info("MQ server shutdown")
 	if mq.isRunning {
+		mq.socket.SetUnsubscribe("hashtx")
+		mq.socket.SetUnsubscribe("hashblock")
 		// if errors in socket.Close or context.Term, let it close ungracefully
 		if err := mq.socket.Close(); err != nil {
 			return err