Merge pull request #2127 from hashicorp/b-remote-consuls-locking

Ensure locking of `Server`'s `remoteConsuls`.

consul/rpc.go

@@ -260,7 +260,13 @@ func (s *Server) globalRPC(method string, args interface{},
 	respCh := make(chan interface{})
 
 	// Make a new request into each datacenter
+	s.remoteLock.RLock()
+	dcs := make([]string, 0, len(s.remoteConsuls))
 	for dc, _ := range s.remoteConsuls {
+		dcs = append(dcs, dc)
+	}
+	s.remoteLock.RUnlock()
+	for _, dc := range dcs {
 		go func(dc string) {
 			rr := reply.New()
 			if err := s.forwardDC(method, dc, args, &rr); err != nil {

consul/server.go

@@ -731,13 +731,16 @@ func (s *Server) Stats() map[string]map[string]string {
 	toString := func(v uint64) string {
 		return strconv.FormatUint(v, 10)
 	}
+	s.remoteLock.RLock()
+	numKnownDCs := len(s.remoteConsuls)
+	s.remoteLock.RUnlock()
 	stats := map[string]map[string]string{
 		"consul": map[string]string{
 			"server":            "true",
 			"leader":            fmt.Sprintf("%v", s.IsLeader()),
 			"leader_addr":       s.raft.Leader(),
 			"bootstrap":         fmt.Sprintf("%v", s.config.Bootstrap),
-			"known_datacenters": toString(uint64(len(s.remoteConsuls))),
+			"known_datacenters": toString(uint64(numKnownDCs)),
 		},
 		"raft":     s.raft.Stats(),
 		"serf_lan": s.serfLAN.Stats(),