[tests] Increase timeout for TestGRPCResolverRoundRobin (jaegertracin…

…g#2729)

* [tests] Add logging for TestGRPCResolverRoundRobin

Signed-off-by: Yuri Shkuro <github@ysh.us>

* rename var for clarity

Signed-off-by: Yuri Shkuro <github@ysh.us>

* cleanup

Signed-off-by: Yuri Shkuro <github@ysh.us>

* increase timeout

Signed-off-by: Yuri Shkuro <github@ysh.us>

pkg/discovery/grpcresolver/grpc_resolver.go

@@ -123,22 +123,25 @@ func (r *Resolver) Close() {
 	r.closing.Wait()
 }
 
+// rendezvousHash is the core of the algorithm. It takes input addresses,
+// assigns each of them a hash, sorts them by those hash values, and
+// returns top N of entries from the sorted list, up to minPeers parameter.
 func (r *Resolver) rendezvousHash(addresses []string) []string {
 	hasher := fnv.New32()
-	hosts := hostScores{}
-	for _, address := range addresses {
-		hosts = append(hosts, hostScore{
+	hosts := make(hostScores, len(addresses))
+	for i, address := range addresses {
+		hosts[i] = hostScore{
 			address: address,
 			score:   hashAddr(hasher, []byte(address), r.salt),
-		})
+		}
 	}
 	sort.Sort(hosts)
-	size := min(r.discoveryMinPeers, len(hosts))
-	addressesPerHost := make([]string, size)
-	for i := 0; i < size; i++ {
-		addressesPerHost[i] = hosts[i].address
+	n := min(r.discoveryMinPeers, len(hosts))
+	topN := make([]string, n)
+	for i := 0; i < n; i++ {
+		topN[i] = hosts[i].address
 	}
-	return addressesPerHost
+	return topN
 }
 
 func min(a, b int) int {
@@ -162,9 +165,9 @@ func (r *Resolver) updateAddresses(hostPorts []string) {
 }
 
 func generateAddresses(instances []string) []resolver.Address {
-	var addrs []resolver.Address
-	for _, instance := range instances {
-		addrs = append(addrs, resolver.Address{Addr: instance})
+	addrs := make([]resolver.Address, len(instances))
+	for i, instance := range instances {
+		addrs[i] = resolver.Address{Addr: instance}
 	}
 	return addrs
 }

pkg/discovery/grpcresolver/grpc_resolver_test.go

@@ -84,19 +84,20 @@ func makeSureConnectionsUp(t *testing.T, count int, testc grpctest.TestServiceCl
 	// Make sure connections to all servers are up.
 	for si := 0; si < count; si++ {
 		connected := false
-		for i := 0; i < 1000; i++ {
+		for i := 0; i < 3000; i++ { // 3000 * 10ms = 30s
 			_, err := testc.EmptyCall(context.Background(), &grpctest.Empty{}, grpc.Peer(&p))
 			if err != nil {
 				continue
 			}
 			if _, ok := addrs[p.Addr.String()]; !ok {
 				addrs[p.Addr.String()] = struct{}{}
 				connected = true
+				t.Logf("connected to peer #%d (%v) on iteration %d", si, p.Addr, i)
 				break
 			}
 			time.Sleep(time.Millisecond * 10)
 		}
-		assert.True(t, connected, "Connection was still not up")
+		assert.True(t, connected, "Connection #%d was still not up. Connections so far: %+v", si, addrs)
 	}
 }
 
@@ -135,10 +136,13 @@ func TestGRPCResolverRoundRobin(t *testing.T) {
 		minPeers    int
 		connections int // expected number of unique connections to servers
 	}{
-		{3, 3}, {5, 5}, {7, 5},
+		{minPeers: 3, connections: 3},
+		{minPeers: 5, connections: 3},
+		// note: test cannot succeed with minPeers < connections because resolver
+		// will never return more than minPeers addresses.
 	}
 	for _, test := range tests {
-		t.Run(fmt.Sprintf("minPeers=%d", test.minPeers), func(t *testing.T) {
+		t.Run(fmt.Sprintf("%+v", test), func(t *testing.T) {
 			res := New(notifier, discoverer, zap.NewNop(), test.minPeers)
 			defer resolver.UnregisterForTesting(res.Scheme())