minimal test for dialing seeds in pex reactor

p2p/pex_reactor.go

@@ -293,16 +293,17 @@ func (r *PEXReactor) ensurePeers() {
 
 	// If we need more addresses, pick a random peer and ask for more.
 	if r.book.NeedMoreAddrs() {
-		if peers := r.Switch.Peers().List(); len(peers) > 0 {
-			i := rand.Int() % len(peers) // nolint: gas
-			peer := peers[i]
-			r.Logger.Info("No addresses to dial. Sending pexRequest to random peer", "peer", peer)
+		peers := r.Switch.Peers().List()
+		peersCount := len(peers)
+		if peersCount > 0 {
+			peer := peers[rand.Int()%peersCount] // nolint: gas
+			r.Logger.Info("We need more addresses. Sending pexRequest to random peer", "peer", peer)
 			r.RequestPEX(peer)
 		}
 	}
 
-	// If we can't connect to any known address, fallback to dialing seeds
-	if numOutPeers+numInPeers+numDialing == 0 {
+	// If we are not connected to nor dialing anybody, fallback to dialing seeds.
+	if numOutPeers+numInPeers+numDialing+len(toDial) == 0 {
 		r.Logger.Info("No addresses to dial nor connected peers. Will dial seeds", "seeds", r.config.Seeds)
 		r.Switch.DialPeersAsync(r.book, r.config.Seeds, false)
 	}

p2p/pex_reactor_test.go

@@ -107,6 +107,7 @@ func TestPEXReactorRunning(t *testing.T) {
 
 func assertSomePeersWithTimeout(t *testing.T, switches []*Switch, checkPeriod, timeout time.Duration) {
 	ticker := time.NewTicker(checkPeriod)
+	remaining := timeout
 	for {
 		select {
 		case <-ticker.C:
@@ -118,16 +119,21 @@ func assertSomePeersWithTimeout(t *testing.T, switches []*Switch, checkPeriod, t
 					allGood = false
 				}
 			}
+			remaining -= checkPeriod
+			if remaining < 0 {
+				remaining = 0
+			}
 			if allGood {
 				return
 			}
-		case <-time.After(timeout):
+		case <-time.After(remaining):
 			numPeersStr := ""
 			for i, s := range switches {
 				outbound, inbound, _ := s.NumPeers()
 				numPeersStr += fmt.Sprintf("%d => {outbound: %d, inbound: %d}, ", i, outbound, inbound)
 			}
 			t.Errorf("expected all switches to be connected to at least one peer (switches: %s)", numPeersStr)
+			return
 		}
 	}
 }
@@ -180,6 +186,47 @@ func TestPEXReactorAbuseFromPeer(t *testing.T) {
 	assert.True(r.ReachedMaxMsgCountForPeer(peer.NodeInfo().ListenAddr))
 }
 
+func TestPEXReactorUsesSeedsIfNeeded(t *testing.T) {
+	dir, err := ioutil.TempDir("", "pex_reactor")
+	require.Nil(t, err)
+	defer os.RemoveAll(dir) // nolint: errcheck
+
+	book := NewAddrBook(dir+"addrbook.json", false)
+	book.SetLogger(log.TestingLogger())
+
+	// 1. create seed
+	seed := makeSwitch(config, 0, "127.0.0.1", "123.123.123", func(i int, sw *Switch) *Switch {
+		sw.SetLogger(log.TestingLogger())
+
+		r := NewPEXReactor(book, &PEXReactorConfig{})
+		r.SetLogger(log.TestingLogger())
+		r.SetEnsurePeersPeriod(250 * time.Millisecond)
+		sw.AddReactor("pex", r)
+		return sw
+	})
+	seed.AddListener(NewDefaultListener("tcp", seed.NodeInfo().ListenAddr, true, log.TestingLogger()))
+	err = seed.Start()
+	require.Nil(t, err)
+	defer seed.Stop()
+
+	// 2. create usual peer
+	sw := makeSwitch(config, 1, "127.0.0.1", "123.123.123", func(i int, sw *Switch) *Switch {
+		sw.SetLogger(log.TestingLogger())
+
+		r := NewPEXReactor(book, &PEXReactorConfig{Seeds: []string{seed.NodeInfo().ListenAddr}})
+		r.SetLogger(log.TestingLogger())
+		r.SetEnsurePeersPeriod(250 * time.Millisecond)
+		sw.AddReactor("pex", r)
+		return sw
+	})
+	err = sw.Start()
+	require.Nil(t, err)
+	defer sw.Stop()
+
+	// 3. check that peer at least connects to seed
+	assertSomePeersWithTimeout(t, []*Switch{sw}, 10*time.Millisecond, 10*time.Second)
+}
+
 func createRoutableAddr() (addr string, netAddr *NetAddress) {
 	for {
 		addr = cmn.Fmt("%v.%v.%v.%v:46656", rand.Int()%256, rand.Int()%256, rand.Int()%256, rand.Int()%256)