fix and tests for backoff connector

backoffconnector.go

@@ -2,30 +2,34 @@ package discovery
 
 import (
 	"context"
+	lru "github.com/hashicorp/golang-lru"
 	"sync"
 	"time"
 
 	"github.com/libp2p/go-libp2p-core/host"
 	"github.com/libp2p/go-libp2p-core/peer"
-
-	"github.com/hashicorp/golang-lru/simplelru"
 )
 
 type BackoffConnector struct {
-	cache      simplelru.LRUCache
+	cache      *lru.TwoQueueCache
 	host       host.Host
 	connTryDur time.Duration
 	backoff    BackoffFactory
 	mux        sync.Mutex
 }
 
-func NewBackoffConnector(h host.Host, cache simplelru.LRUCache, connectionTryDuration time.Duration, backoff BackoffFactory) *BackoffConnector {
+func NewBackoffConnector(h host.Host, cacheSize int, connectionTryDuration time.Duration, backoff BackoffFactory) (*BackoffConnector, error) {
+	cache, err := lru.New2Q(cacheSize)
+	if err != nil {
+		return nil, err
+	}
+
 	return &BackoffConnector{
 		cache:      cache,
 		host:       h,
 		connTryDur: connectionTryDuration,
 		backoff:    backoff,
-	}
+	}, nil
 }
 
 type connCacheData struct {
@@ -62,6 +66,7 @@ func (c *BackoffConnector) Connect(ctx context.Context, peerCh <-chan peer.AddrI
 				cachedPeer.nextTry = time.Now().Add(cachedPeer.strat.Delay())
 				c.cache.Add(pi.ID, cachedPeer)
 			}
+			c.mux.Unlock()
 
 			go func(pi peer.AddrInfo) {
 				ctx, cancel := context.WithTimeout(ctx, c.connTryDur)

backoffconnector_test.go

@@ -0,0 +1,108 @@
+package discovery
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"testing"
+	"time"
+
+	bhost "github.com/libp2p/go-libp2p-blankhost"
+	"github.com/libp2p/go-libp2p-core/host"
+	"github.com/libp2p/go-libp2p-core/peer"
+	swarmt "github.com/libp2p/go-libp2p-swarm/testing"
+)
+
+type maxDialHost struct {
+	host.Host
+
+	mux            sync.Mutex
+	timesDialed    map[peer.ID]int
+	maxTimesToDial map[peer.ID]int
+}
+
+func (h *maxDialHost) Connect(ctx context.Context, ai peer.AddrInfo) error {
+	pid := ai.ID
+
+	h.mux.Lock()
+	defer h.mux.Unlock()
+	numDials := h.timesDialed[pid]
+	numDials += 1
+	h.timesDialed[pid] = numDials
+
+	if maxDials, ok := h.maxTimesToDial[pid]; ok && numDials > maxDials {
+		return fmt.Errorf("should not be dialing peer %s", pid.String())
+	}
+
+	return h.Host.Connect(ctx, ai)
+}
+
+func getNetHosts(t *testing.T, ctx context.Context, n int) []host.Host {
+	var out []host.Host
+
+	for i := 0; i < n; i++ {
+		netw := swarmt.GenSwarm(t, ctx)
+		h := bhost.NewBlankHost(netw)
+		out = append(out, h)
+	}
+
+	return out
+}
+
+func loadCh(peers []host.Host) <-chan peer.AddrInfo {
+	ch := make(chan peer.AddrInfo, len(peers))
+	for _, p := range peers {
+		ch <- p.Peerstore().PeerInfo(p.ID())
+	}
+	close(ch)
+	return ch
+}
+
+func TestBackoffConnector(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+
+	hosts := getNetHosts(t, ctx, 5)
+	primary := &maxDialHost{
+		Host:        hosts[0],
+		mux:         sync.Mutex{},
+		timesDialed: make(map[peer.ID]int),
+		maxTimesToDial: map[peer.ID]int{
+			hosts[1].ID(): 1,
+			hosts[2].ID(): 2,
+		},
+	}
+
+	bc, err := NewBackoffConnector(primary, 10, time.Minute, NewFixedBackoff(time.Millisecond*1500))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	bc.Connect(ctx, loadCh(hosts))
+
+	time.Sleep(time.Millisecond * 100)
+	if expected, actual := len(hosts) - 1, len(primary.Network().Conns()); actual != expected {
+		t.Fatalf("wrong number of connections. expected %d, actual %d", expected, actual)
+	}
+
+	for _, c := range primary.Network().Conns() {
+		c.Close()
+	}
+
+	for len(primary.Network().Conns()) > 0 {
+		time.Sleep(time.Millisecond * 100)
+	}
+
+	bc.Connect(ctx, loadCh(hosts))
+	if numConns := len(primary.Network().Conns()); numConns != 0 {
+		t.Fatal("shouldn't be connected to any peers")
+	}
+
+	time.Sleep(time.Millisecond * 1600)
+	bc.Connect(ctx, loadCh(hosts))
+
+	time.Sleep(time.Millisecond * 100)
+	if expected, actual := len(hosts) - 2, len(primary.Network().Conns()); actual != expected {
+		t.Fatalf("wrong number of connections. expected %d, actual %d", expected, actual)
+	}
+}

go.mod

@@ -1,6 +1,7 @@
 module github.com/libp2p/go-libp2p-discovery
 
 require (
+	github.com/hashicorp/golang-lru v0.5.1
 	github.com/ipfs/go-cid v0.0.2
 	github.com/ipfs/go-log v0.0.1
 	github.com/libp2p/go-libp2p-blankhost v0.1.1

go.sum

@@ -33,6 +33,7 @@ github.com/gxed/hashland/keccakpg v0.0.1 h1:wrk3uMNaMxbXiHibbPO4S0ymqJMm41WiudyF
 github.com/gxed/hashland/keccakpg v0.0.1/go.mod h1:kRzw3HkwxFU1mpmPP8v1WyQzwdGfmKFJ6tItnhQ67kU=
 github.com/gxed/hashland/murmur3 v0.0.1 h1:SheiaIt0sda5K+8FLz952/1iWS9zrnKsEJaOJu4ZbSc=
 github.com/gxed/hashland/murmur3 v0.0.1/go.mod h1:KjXop02n4/ckmZSnY2+HKcLud/tcmvhST0bie/0lS48=
+github.com/hashicorp/golang-lru v0.5.1 h1:0hERBMJE1eitiLkihrMvRVBYAkpHzc/J3QdDN+dAcgU=
 github.com/hashicorp/golang-lru v0.5.1/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
 github.com/hpcloud/tail v1.0.0 h1:nfCOvKYfkgYP8hkirhJocXT2+zOD8yUNjXaWfTlyFKI=
 github.com/hpcloud/tail v1.0.0/go.mod h1:ab1qPbhIpdTxEkNHXyeSf5vhxWSCs/tWer42PpOxQnU=