Updates Serf to pick up intent queue fix.

This fixes #1062 by storing intents per-node instead of in a small, fixed-
size circular buffer.

vendor/github.com/hashicorp/serf/serf/config.go

@@ -121,12 +121,12 @@ type Config struct {
 	// prevent an unbounded growth of memory utilization
 	MaxQueueDepth int
 
-	// RecentIntentBuffer is used to set the size of recent join and leave intent
+	// RecentIntentTimeout is used to determine how long we store recent
-	// messages that will be buffered. This is used to guard against
+	// join and leave intents. This is used to guard against the case where
-	// the case where Serf broadcasts an intent that arrives before the
+	// Serf broadcasts an intent that arrives before the Memberlist event.
-	// Memberlist event. It is important that this not be too small to avoid
+	// It is important that this not be too short to avoid continuous
-	// continuous rebroadcasting of dead events.
+	// rebroadcasting of dead events.
-	RecentIntentBuffer int
+	RecentIntentTimeout time.Duration
 
 	// EventBuffer is used to control how many events are buffered.
 	// This is used to prevent re-delivery of events to a client. The buffer
@@ -242,7 +242,7 @@ func DefaultConfig() *Config {
 		LogOutput:                    os.Stderr,
 		ProtocolVersion:              ProtocolVersionMax,
 		ReapInterval:                 15 * time.Second,
-		RecentIntentBuffer:           128,
+		RecentIntentTimeout:          5 * time.Minute,
 		ReconnectInterval:            30 * time.Second,
 		ReconnectTimeout:             24 * time.Hour,
 		QueueDepthWarning:            128,

vendor/github.com/hashicorp/serf/serf/serf.go

@@ -65,12 +65,11 @@ type Serf struct {
 	memberLock    sync.RWMutex
 	members       map[string]*memberState
 
-	// Circular buffers for recent intents, used
+	// recentIntents the lamport time and type of intent for a given node in
-	// in case we get the intent before the relevant event
+	// case we get an intent before the relevant memberlist event. This is
-	recentLeave      []nodeIntent
+	// indexed by node, and always store the latest lamport time / intent
-	recentLeaveIndex int
+	// we've seen. The memberLock protects this structure.
-	recentJoin       []nodeIntent
+	recentIntents map[string]nodeIntent
-	recentJoinIndex  int
 
 	eventBroadcasts *memberlist.TransmitLimitedQueue
 	eventBuffer     []*userEvents
@@ -179,10 +178,18 @@ type memberState struct {
 	leaveTime   time.Time   // wall clock time of leave
 }
 
-// nodeIntent is used to buffer intents for out-of-order deliveries
+// nodeIntent is used to buffer intents for out-of-order deliveries.
 type nodeIntent struct {
+	// Type is the intent being tracked. Only messageJoinType and
+	// messageLeaveType are tracked.
+	Type messageType
+
+	// WallTime is the wall clock time we saw this intent in order to
+	// expire it from the buffer.
+	WallTime time.Time
+
+	// LTime is the Lamport time, used for cluster-wide ordering of events.
 	LTime LamportTime
-	Node  string
 }
 
 // userEvent is used to buffer events to prevent re-delivery
@@ -340,8 +347,7 @@ func Create(conf *Config) (*Serf, error) {
 	}
 
 	// Create the buffer for recent intents
-	serf.recentJoin = make([]nodeIntent, conf.RecentIntentBuffer)
+	serf.recentIntents = make(map[string]nodeIntent)
-	serf.recentLeave = make([]nodeIntent, conf.RecentIntentBuffer)
 
 	// Create a buffer for events and queries
 	serf.eventBuffer = make([]*userEvents, conf.EventBuffer)
@@ -855,17 +861,15 @@ func (s *Serf) handleNodeJoin(n *memberlist.Node) {
 			},
 		}
 
-		// Check if we have a join intent and use the LTime
+		// Check if we have a join or leave intent. The intent buffer
-		if join := recentIntent(s.recentJoin, n.Name); join != nil {
+		// will only hold one event for this node, so the more recent
-			member.statusLTime = join.LTime
+		// one will take effect.
+		if join, ok := recentIntent(s.recentIntents, n.Name, messageJoinType); ok {
+			member.statusLTime = join
 		}
-
+		if leave, ok := recentIntent(s.recentIntents, n.Name, messageLeaveType); ok {
-		// Check if we have a leave intent
+			member.Status = StatusLeaving
-		if leave := recentIntent(s.recentLeave, n.Name); leave != nil {
+			member.statusLTime = leave
-			if leave.LTime > member.statusLTime {
-				member.Status = StatusLeaving
-				member.statusLTime = leave.LTime
-			}
 		}
 
 		s.members[n.Name] = member
@@ -1016,18 +1020,8 @@ func (s *Serf) handleNodeLeaveIntent(leaveMsg *messageLeave) bool {
 
 	member, ok := s.members[leaveMsg.Node]
 	if !ok {
-		// If we've already seen this message don't rebroadcast
+		// Rebroadcast only if this was an update we hadn't seen before.
-		if recentIntent(s.recentLeave, leaveMsg.Node) != nil {
+		return upsertIntent(s.recentIntents, leaveMsg.Node, messageLeaveType, leaveMsg.LTime, time.Now)
-			return false
-		}
-
-		// We don't know this member so store it in a buffer for now
-		s.recentLeave[s.recentLeaveIndex] = nodeIntent{
-			LTime: leaveMsg.LTime,
-			Node:  leaveMsg.Node,
-		}
-		s.recentLeaveIndex = (s.recentLeaveIndex + 1) % len(s.recentLeave)
-		return true
 	}
 
 	// If the message is old, then it is irrelevant and we can skip it
@@ -1087,15 +1081,8 @@ func (s *Serf) handleNodeJoinIntent(joinMsg *messageJoin) bool {
 
 	member, ok := s.members[joinMsg.Node]
 	if !ok {
-		// If we've already seen this message don't rebroadcast
+		// Rebroadcast only if this was an update we hadn't seen before.
-		if recentIntent(s.recentJoin, joinMsg.Node) != nil {
+		return upsertIntent(s.recentIntents, joinMsg.Node, messageJoinType, joinMsg.LTime, time.Now)
-			return false
-		}
-
-		// We don't know this member so store it in a buffer for now
-		s.recentJoin[s.recentJoinIndex] = nodeIntent{LTime: joinMsg.LTime, Node: joinMsg.Node}
-		s.recentJoinIndex = (s.recentJoinIndex + 1) % len(s.recentJoin)
-		return true
 	}
 
 	// Check if this time is newer than what we have
@@ -1387,14 +1374,17 @@ func (s *Serf) resolveNodeConflict() {
 	}
 }
 
-// handleReap periodically reaps the list of failed and left members.
+// handleReap periodically reaps the list of failed and left members, as well
+// as old buffered intents.
 func (s *Serf) handleReap() {
 	for {
 		select {
 		case <-time.After(s.config.ReapInterval):
 			s.memberLock.Lock()
-			s.failedMembers = s.reap(s.failedMembers, s.config.ReconnectTimeout)
+			now := time.Now()
-			s.leftMembers = s.reap(s.leftMembers, s.config.TombstoneTimeout)
+			s.failedMembers = s.reap(s.failedMembers, now, s.config.ReconnectTimeout)
+			s.leftMembers = s.reap(s.leftMembers, now, s.config.TombstoneTimeout)
+			reapIntents(s.recentIntents, now, s.config.RecentIntentTimeout)
 			s.memberLock.Unlock()
 		case <-s.shutdownCh:
 			return
@@ -1418,8 +1408,7 @@ func (s *Serf) handleReconnect() {
 // reap is called with a list of old members and a timeout, and removes
 // members that have exceeded the timeout. The members are removed from
 // both the old list and the members itself. Locking is left to the caller.
-func (s *Serf) reap(old []*memberState, timeout time.Duration) []*memberState {
+func (s *Serf) reap(old []*memberState, now time.Time, timeout time.Duration) []*memberState {
-	now := time.Now()
 	n := len(old)
 	for i := 0; i < n; i++ {
 		m := old[i]
@@ -1490,7 +1479,7 @@ func (s *Serf) reconnect() {
 	}
 
 	// Select a random member to try and join
-	idx := int(rand.Uint32() % uint32(n))
+	idx := rand.Int31n(int32(n))
 	mem := s.failedMembers[idx]
 	s.memberLock.RUnlock()
 
@@ -1538,24 +1527,46 @@ func removeOldMember(old []*memberState, name string) []*memberState {
 	return old
 }
 
-// recentIntent checks the recent intent buffer for a matching
+// reapIntents clears out any intents that are older than the timeout. Make sure
-// entry for a given node, and either returns the message or nil
+// the memberLock is held when passing in the Serf instance's recentIntents
-func recentIntent(recent []nodeIntent, node string) (intent *nodeIntent) {
+// member.
-	for i := 0; i < len(recent); i++ {
+func reapIntents(intents map[string]nodeIntent, now time.Time, timeout time.Duration) {
-		// Break fast if we hit a zero entry
+	for node, intent := range intents {
-		if recent[i].LTime == 0 {
+		if now.Sub(intent.WallTime) > timeout {
-			break
+			delete(intents, node)
-		}
-
-		// Check for a node match
-		if recent[i].Node == node {
-			// Take the most recent entry
-			if intent == nil || recent[i].LTime > intent.LTime {
-				intent = &recent[i]
-			}
 		}
 	}
-	return
+}
+
+// upsertIntent will update an existing intent with the supplied Lamport time,
+// or create a new entry. This will return true if a new entry was added. The
+// stamper is used to capture the wall clock time for expiring these buffered
+// intents. Make sure the memberLock is held when passing in the Serf instance's
+// recentIntents member.
+func upsertIntent(intents map[string]nodeIntent, node string, itype messageType,
+	ltime LamportTime, stamper func() time.Time) bool {
+	if intent, ok := intents[node]; !ok || ltime > intent.LTime {
+		intents[node] = nodeIntent{
+			Type:     itype,
+			WallTime: stamper(),
+			LTime:    ltime,
+		}
+		return true
+	}
+
+	return false
+}
+
+// recentIntent checks the recent intent buffer for a matching entry for a given
+// node, and returns the Lamport time, if an intent is present, indicated by the
+// returned boolean. Make sure the memberLock is held for read when passing in
+// the Serf instance's recentIntents member.
+func recentIntent(intents map[string]nodeIntent, node string, itype messageType) (LamportTime, bool) {
+	if intent, ok := intents[node]; ok && intent.Type == itype {
+		return intent.LTime, true
+	}
+
+	return LamportTime(0), false
 }
 
 // handleRejoin attempts to reconnect to previously known alive nodes

vendor/vendor.json

@@ -276,14 +276,18 @@
 			"revision": "84989fd23ad4cc0e7ad44d6a871fd793eb9beb0a"
 		},
 		{
+			"checksumSHA1": "E3Xcanc9ouQwL+CZGOUyA/+giLg=",
 			"comment": "v0.7.0-66-g6c4672d",
 			"path": "github.com/hashicorp/serf/coordinate",
-			"revision": "6c4672d66fc6312ddde18399262943e21175d831"
+			"revision": "114430d8210835d66defdc31cdc176c58e060005",
+			"revisionTime": "2016-08-09T01:42:04Z"
 		},
 		{
+			"checksumSHA1": "vLyudzMEdik8IpRY1H2vRa2PeLU=",
 			"comment": "v0.7.0-66-g6c4672d",
 			"path": "github.com/hashicorp/serf/serf",
-			"revision": "6c4672d66fc6312ddde18399262943e21175d831"
+			"revision": "114430d8210835d66defdc31cdc176c58e060005",
+			"revisionTime": "2016-08-09T01:42:04Z"
 		},
 		{
 			"path": "github.com/hashicorp/yamux",