From 20c67f218cc7ed03e436ae52fe1a1d49ef399a66 Mon Sep 17 00:00:00 2001
From: Armon Dadgar <armon.dadgar@gmail.com>
Date: Thu, 4 Jun 2015 12:42:56 +0200
Subject: [PATCH] nomad: adding reconcile channel

---
 nomad/serf.go   | 34 ++++++++++++++++++++++++++++++++--
 nomad/server.go | 18 ++++++++++++------
 2 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/nomad/serf.go b/nomad/serf.go
index 464b5cfb3..f8b0600a4 100644
--- a/nomad/serf.go
+++ b/nomad/serf.go
@@ -2,6 +2,12 @@ package nomad
 
 import "github.com/hashicorp/serf/serf"
 
+const (
+	// StatusReap is used to update the status of a node if we
+	// are handling a EventMemberReap
+	StatusReap = serf.MemberStatus(-1)
+)
+
 // serfEventHandler is used to handle events from the serf cluster
 func (s *Server) serfEventHandler() {
 	for {
@@ -10,8 +16,10 @@ func (s *Server) serfEventHandler() {
 			switch e.EventType() {
 			case serf.EventMemberJoin:
 				s.nodeJoin(e.(serf.MemberEvent))
+				s.localMemberEvent(e.(serf.MemberEvent))
 			case serf.EventMemberLeave, serf.EventMemberFailed:
 				s.nodeFailed(e.(serf.MemberEvent))
+				s.localMemberEvent(e.(serf.MemberEvent))
 			case serf.EventMemberUpdate, serf.EventMemberReap,
 				serf.EventUser, serf.EventQuery: // Ignore
 			default:
@@ -52,8 +60,6 @@ func (s *Server) nodeJoin(me serf.MemberEvent) {
 		}
 		s.peerLock.Unlock()
 
-		// TODO: Add as Raft peer
-
 		// If we still expecting to bootstrap, may need to handle this
 		if s.config.BootstrapExpect != 0 {
 			s.maybeBootstrap()
@@ -153,3 +159,27 @@ func (s *Server) nodeFailed(me serf.MemberEvent) {
 	//    }
 	//}
 }
+
+// localMemberEvent is used to reconcile Serf events with the
+// consistent store if we are the current leader.
+func (s *Server) localMemberEvent(me serf.MemberEvent) {
+	// Do nothing if we are not the leader
+	if !s.IsLeader() {
+		return
+	}
+
+	// Check if this is a reap event
+	isReap := me.EventType() == serf.EventMemberReap
+
+	// Queue the members for reconciliation
+	for _, m := range me.Members {
+		// Change the status if this is a reap event
+		if isReap {
+			m.Status = StatusReap
+		}
+		select {
+		case s.reconcileCh <- m:
+		default:
+		}
+	}
+}
diff --git a/nomad/server.go b/nomad/server.go
index 50e3a50a5..9bd086b4d 100644
--- a/nomad/server.go
+++ b/nomad/server.go
@@ -73,6 +73,11 @@ type Server struct {
 	// and automatic clustering within regions.
 	serf *serf.Serf
 
+	// reconcileCh is used to pass events from the serf handler
+	// into the leader manager. Mostly used to handle when servers
+	// join/leave from the region.
+	reconcileCh chan serf.Member
+
 	// eventCh is used to receive events from the serf cluster
 	eventCh chan serf.Event
 
@@ -105,12 +110,13 @@ func NewServer(config *Config) (*Server, error) {
 
 	// Create the server
 	s := &Server{
-		config:     config,
-		logger:     logger,
-		rpcServer:  rpc.NewServer(),
-		peers:      make(map[string][]*serverParts),
-		eventCh:    make(chan serf.Event, 256),
-		shutdownCh: make(chan struct{}),
+		config:      config,
+		logger:      logger,
+		rpcServer:   rpc.NewServer(),
+		peers:       make(map[string][]*serverParts),
+		reconcileCh: make(chan serf.Member, 32),
+		eventCh:     make(chan serf.Event, 256),
+		shutdownCh:  make(chan struct{}),
 	}
 
 	// Initialize the RPC layer