pull overlay parameters into the GossipSubRouter struct

pacify the race detector in travis

gossipsub.go

@@ -107,7 +107,14 @@ func NewGossipSub(ctx context.Context, h host.Host, opts ...Option) (*PubSub, er
 		iasked:   make(map[peer.ID]int),
 		connect:  make(chan connectInfo, GossipSubMaxPendingConnections),
 		mcache:   NewMessageCache(GossipSubHistoryGossip, GossipSubHistoryLength),
+
 		// these must be pulled in to resolve races in tests... sigh.
+		D:      GossipSubD,
+		Dlo:    GossipSubDlo,
+		Dhi:    GossipSubDhi,
+		Dscore: GossipSubDscore,
+		Dlazy:  GossipSubDlazy,
+
 		directConnectTicks:      GossipSubDirectConnectTicks,
 		opportunisticGraftTicks: GossipSubOpportunisticGraftTicks,
 	}
@@ -262,6 +269,11 @@ type GossipSubRouter struct {
 	// clean up -- eg backoff clean up.
 	heartbeatTicks uint64
 
+	// overly parameter "constants"
+	// these are pulled from their global value or else the race detector is angry on travis
+	// it also allows us to change them per peer in tests, which is a plus
+	D, Dlo, Dhi, Dscore, Dlazy int
+
 	// tick "constants" for triggering direct connect and opportunistic grafting
 	// these are pulled from their global value or else the race detector is angry on travis
 	directConnectTicks, opportunisticGraftTicks uint64
@@ -352,10 +364,10 @@ func (gs *GossipSubRouter) EnoughPeers(topic string, suggested int) bool {
 	gsPeers = len(gs.mesh[topic])
 
 	if suggested == 0 {
-		suggested = GossipSubDlo
+		suggested = gs.Dlo
 	}
 
-	if fsPeers+gsPeers >= suggested || gsPeers >= GossipSubDhi {
+	if fsPeers+gsPeers >= suggested || gsPeers >= gs.Dhi {
 		return true
 	}
 
@@ -741,7 +753,7 @@ func (gs *GossipSubRouter) Publish(msg *Message) {
 			gmap, ok = gs.fanout[topic]
 			if !ok || len(gmap) == 0 {
 				// we don't have any, pick some with score above the publish threshold
-				peers := gs.getPeers(topic, GossipSubD, func(p peer.ID) bool {
+				peers := gs.getPeers(topic, gs.D, func(p peer.ID) bool {
 					return gs.score.Score(p) >= gs.publishThreshold
 				})
 
@@ -787,9 +799,9 @@ func (gs *GossipSubRouter) Join(topic string) {
 			}
 		}
 
-		if len(gmap) < GossipSubD {
+		if len(gmap) < gs.D {
 			// we need more peers; eager, as this would get fixed in the next heartbeat
-			more := gs.getPeers(topic, GossipSubD-len(gmap), func(p peer.ID) bool {
+			more := gs.getPeers(topic, gs.D-len(gmap), func(p peer.ID) bool {
 				// filter our current peers, direct peers, and peers with negative scores
 				_, inMesh := gmap[p]
 				_, direct := gs.direct[p]
@@ -803,7 +815,7 @@ func (gs *GossipSubRouter) Join(topic string) {
 		delete(gs.fanout, topic)
 		delete(gs.lastpub, topic)
 	} else {
-		peers := gs.getPeers(topic, GossipSubD, func(p peer.ID) bool {
+		peers := gs.getPeers(topic, gs.D, func(p peer.ID) bool {
 			// filter direct peers and peers with negative score
 			_, direct := gs.direct[p]
 			return !direct && gs.score.Score(p) >= 0
@@ -973,9 +985,9 @@ func (gs *GossipSubRouter) heartbeat() {
 		}
 
 		// do we have enough peers?
-		if l := len(peers); l < GossipSubDlo {
+		if l := len(peers); l < gs.Dlo {
 			backoff := gs.backoff[topic]
-			ineed := GossipSubD - l
+			ineed := gs.D - l
 			plst := gs.getPeers(topic, ineed, func(p peer.ID) bool {
 				// filter our current and direct peers, peers we are backing off, and peers with negative score
 				_, inMesh := peers[p]
@@ -990,7 +1002,7 @@ func (gs *GossipSubRouter) heartbeat() {
 		}
 
 		// do we have too many peers?
-		if len(peers) > GossipSubDhi {
+		if len(peers) > gs.Dhi {
 			plst := peerMapToList(peers)
 
 			// sort by score (but shuffle first for the case we don't use the score)
@@ -1000,8 +1012,8 @@ func (gs *GossipSubRouter) heartbeat() {
 			})
 
 			// We keep the first D_score peers by score and the remaining up to D_lo randomly
-			shufflePeers(plst[GossipSubDscore:])
-			for _, p := range plst[GossipSubD:] {
+			shufflePeers(plst[gs.Dscore:])
+			for _, p := range plst[gs.D:] {
 				log.Debugf("HEARTBEAT: Remove mesh link to %s in %s", p, topic)
 				prunePeer(p)
 			}
@@ -1075,8 +1087,8 @@ func (gs *GossipSubRouter) heartbeat() {
 		}
 
 		// do we need more peers?
-		if len(peers) < GossipSubD {
-			ineed := GossipSubD - len(peers)
+		if len(peers) < gs.D {
+			ineed := gs.D - len(peers)
 			plst := gs.getPeers(topic, ineed, func(p peer.ID) bool {
 				// filter our current and direct peers and peers with score above the publish threshold
 				_, inFanout := peers[p]
@@ -1222,7 +1234,7 @@ func (gs *GossipSubRouter) emitGossip(topic string, exclude map[peer.ID]struct{}
 		}
 	}
 
-	target := GossipSubDlazy
+	target := gs.Dlazy
 	factor := int(GossipSubGossipFactor * float64(len(peers)))
 	if factor > target {
 		target = factor