Updates Serf to pull in new queue depth controls.

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

@@ -112,6 +112,10 @@ type Config struct {
 	// node.
 	FlapTimeout time.Duration
 
+	// QueueCheckInterval is the interval at which we check the message
+	// queue to apply the warning and max depth.
+	QueueCheckInterval time.Duration
+
 	// QueueDepthWarning is used to generate warning message if the
 	// number of queued messages to broadcast exceeds this number. This
 	// is to provide the user feedback if events are being triggered
@@ -123,6 +127,12 @@ type Config struct {
 	// prevent an unbounded growth of memory utilization
 	MaxQueueDepth int
 
+	// MinQueueDepth, if >0 will enforce a lower limit for dropping messages
+	// and then the max will be max(MinQueueDepth, 2*SizeOfCluster). This
+	// defaults to 0 which disables this dynamic sizing feature. If this is
+	// >0 then MaxQueueDepth will be ignored.
+	MinQueueDepth int
+
 	// RecentIntentTimeout is used to determine how long we store recent
 	// join and leave intents. This is used to guard against the case where
 	// Serf broadcasts an intent that arrives before the Memberlist event.
@@ -253,6 +263,7 @@ func DefaultConfig() *Config {
 		RecentIntentTimeout:          5 * time.Minute,
 		ReconnectInterval:            30 * time.Second,
 		ReconnectTimeout:             24 * time.Hour,
+		QueueCheckInterval:           30 * time.Second,
 		QueueDepthWarning:            128,
 		MaxQueueDepth:                4096,
 		TombstoneTimeout:             24 * time.Hour,

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

@@ -1515,21 +1515,37 @@ func (s *Serf) reconnect() {
 	s.memberlist.Join([]string{addr.String()})
 }
 
+// getQueueMax will get the maximum queue depth, which might be dynamic depending
+// on how Serf is configured.
+func (s *Serf) getQueueMax() int {
+	max := s.config.MaxQueueDepth
+	if s.config.MinQueueDepth > 0 {
+		s.memberLock.RLock()
+		max = 2 * len(s.members)
+		s.memberLock.RUnlock()
+
+		if max < s.config.MinQueueDepth {
+			max = s.config.MinQueueDepth
+		}
+	}
+	return max
+}
+
 // checkQueueDepth periodically checks the size of a queue to see if
 // it is too large
 func (s *Serf) checkQueueDepth(name string, queue *memberlist.TransmitLimitedQueue) {
 	for {
 		select {
-		case <-time.After(time.Second):
+		case <-time.After(s.config.QueueCheckInterval):
 			numq := queue.NumQueued()
 			metrics.AddSample([]string{"serf", "queue", name}, float32(numq))
 			if numq >= s.config.QueueDepthWarning {
 				s.logger.Printf("[WARN] serf: %s queue depth: %d", name, numq)
 			}
-			if numq > s.config.MaxQueueDepth {
+			if max := s.getQueueMax(); numq > max {
 				s.logger.Printf("[WARN] serf: %s queue depth (%d) exceeds limit (%d), dropping messages!",
-					name, numq, s.config.MaxQueueDepth)
+					name, numq, max)
-				queue.Prune(s.config.MaxQueueDepth)
+				queue.Prune(max)
 			}
 		case <-s.shutdownCh:
 			return

vendor/vendor.json

@@ -64,7 +64,7 @@
 		{"path":"github.com/hashicorp/raft","checksumSHA1":"JjJtGJi1ywWhVhs/PvTXxe4TeD8=","revision":"6d14f0c70869faabd9e60ba7ed88a6cbbd6a661f","revisionTime":"2017-10-03T22:09:13Z","version":"v1.0.0","versionExact":"v1.0.0"},
 		{"path":"github.com/hashicorp/raft-boltdb","checksumSHA1":"QAxukkv54/iIvLfsUP6IK4R0m/A=","revision":"d1e82c1ec3f15ee991f7cc7ffd5b67ff6f5bbaee","revisionTime":"2015-02-01T20:08:39Z"},
 		{"path":"github.com/hashicorp/serf/coordinate","checksumSHA1":"mS15CkImPzXYsgNwl3Mt9Gh3Vb0=","comment":"v0.7.0-66-g6c4672d","revision":"c20a0b1b1ea9eb8168bcdec0116688fa9254e449","revisionTime":"2017-10-22T02:00:50Z"},
-		{"path":"github.com/hashicorp/serf/serf","checksumSHA1":"iYhCWgAAUcQjU0JocsKgak5C8tY=","comment":"v0.7.0-66-g6c4672d","revision":"c20a0b1b1ea9eb8168bcdec0116688fa9254e449","revisionTime":"2017-10-22T02:00:50Z"},
+		{"path":"github.com/hashicorp/serf/serf","checksumSHA1":"NegZzEwYOlfkbvy+jTBkX3OBcRM=","comment":"v0.7.0-66-g6c4672d","revision":"a110af454b635c75adc2b7eee541af2c68666d97","revisionTime":"2017-12-07T01:04:04Z"},
 		{"path":"github.com/hashicorp/yamux","checksumSHA1":"ZhK6IO2XN81Y+3RAjTcVm1Ic7oU=","revision":"d1caa6c97c9fc1cc9e83bbe34d0603f9ff0ce8bd","revisionTime":"2016-07-20T23:31:40Z"},
 		{"path":"github.com/mattn/go-isatty","checksumSHA1":"xZuhljnmBysJPta/lMyYmJdujCg=","revision":"66b8e73f3f5cda9f96b69efd03dd3d7fc4a5cdb8","revisionTime":"2016-08-06T12:27:52Z"},
 		{"path":"github.com/miekg/dns","checksumSHA1":"Jo+pItYOocIRdoFL0fc4nHhUEJY=","revision":"bbca4873b326f5dc54bfe31148446d4ed79a5a02","revisionTime":"2017-08-08T22:19:10Z"},