From d737a2204a4d78c8c475bbe9ecc94ab72d32cb12 Mon Sep 17 00:00:00 2001
From: Armon Dadgar <armon.dadgar@gmail.com>
Date: Tue, 27 May 2014 15:45:19 -0700
Subject: [PATCH] consul: Pass protocol version for leader forwarding

---
 consul/rpc.go    | 14 ++++++++++++--
 consul/serf.go   | 20 +++++++++++++++++---
 consul/server.go |  6 ++++++
 3 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/consul/rpc.go b/consul/rpc.go
index 478bbd8ef9..60ad5c422e 100644
--- a/consul/rpc.go
+++ b/consul/rpc.go
@@ -182,12 +182,22 @@ func (s *Server) forward(method string, info structs.RPCInfo, args interface{},
 
 // forwardLeader is used to forward an RPC call to the leader, or fail if no leader
 func (s *Server) forwardLeader(method string, args interface{}, reply interface{}) error {
+	// Get the leader
 	leader := s.raft.Leader()
 	if leader == nil {
 		return structs.ErrNoLeader
 	}
-	// TODO: Correct version
-	return s.connPool.RPC(leader, 1, method, args, reply)
+
+	// Lookup the server
+	s.localLock.RLock()
+	server := s.localConsuls[leader.String()]
+	s.localLock.RUnlock()
+
+	// Handle a missing server
+	if server == nil {
+		return structs.ErrNoLeader
+	}
+	return s.connPool.RPC(server.Addr, server.Version, method, args, reply)
 }
 
 // forwardDC is used to forward an RPC call to a remote DC, or fail if no servers
diff --git a/consul/serf.go b/consul/serf.go
index c90bacbb79..11a48ee471 100644
--- a/consul/serf.go
+++ b/consul/serf.go
@@ -24,7 +24,7 @@ func (s *Server) lanEventHandler() {
 			case serf.EventMemberLeave:
 				fallthrough
 			case serf.EventMemberFailed:
-				s.nodeFailed(e.(serf.MemberEvent))
+				s.nodeFailed(e.(serf.MemberEvent), false)
 				s.localMemberEvent(e.(serf.MemberEvent))
 
 			case serf.EventMemberReap:
@@ -54,7 +54,7 @@ func (s *Server) wanEventHandler() {
 			case serf.EventMemberLeave:
 				fallthrough
 			case serf.EventMemberFailed:
-				s.nodeFailed(e.(serf.MemberEvent))
+				s.nodeFailed(e.(serf.MemberEvent), true)
 			case serf.EventMemberUpdate: // Ignore
 			case serf.EventMemberReap: // Ignore
 			case serf.EventUser:
@@ -142,11 +142,18 @@ func (s *Server) nodeJoin(me serf.MemberEvent, wan bool) {
 			s.remoteConsuls[parts.Datacenter] = append(existing, parts)
 		}
 		s.remoteLock.Unlock()
+
+		// Add to the local list as well
+		if !wan {
+			s.localLock.Lock()
+			s.localConsuls[parts.Addr.String()] = parts
+			s.localLock.Unlock()
+		}
 	}
 }
 
 // nodeFailed is used to handle fail events on both the serf clustes
-func (s *Server) nodeFailed(me serf.MemberEvent) {
+func (s *Server) nodeFailed(me serf.MemberEvent, wan bool) {
 	for _, m := range me.Members {
 		ok, parts := isConsulServer(m)
 		if !ok {
@@ -174,5 +181,12 @@ func (s *Server) nodeFailed(me serf.MemberEvent) {
 			s.remoteConsuls[parts.Datacenter] = existing
 		}
 		s.remoteLock.Unlock()
+
+		// Remove from the local list as well
+		if !wan {
+			s.localLock.Lock()
+			delete(s.localConsuls, parts.Addr.String())
+			s.localLock.Unlock()
+		}
 	}
 }
diff --git a/consul/server.go b/consul/server.go
index ba2976192a..6b1603dd65 100644
--- a/consul/server.go
+++ b/consul/server.go
@@ -68,6 +68,11 @@ type Server struct {
 	// Have we attempted to leave the cluster
 	left bool
 
+	// localConsuls is used to track the known consuls
+	// in the local data center. Used to do leader forwarding.
+	localConsuls map[string]*serverParts
+	localLock    sync.RWMutex
+
 	// Logger uses the provided LogOutput
 	logger *log.Logger
 
@@ -161,6 +166,7 @@ func NewServer(config *Config) (*Server, error) {
 		connPool:      NewPool(serverRPCCache, serverMaxStreams, tlsConfig),
 		eventChLAN:    make(chan serf.Event, 256),
 		eventChWAN:    make(chan serf.Event, 256),
+		localConsuls:  make(map[string]*serverParts),
 		logger:        logger,
 		reconcileCh:   make(chan serf.Member, 32),
 		remoteConsuls: make(map[string][]*serverParts),