From 57510d2fec021bfcd3b8f806f8fe82efb0d3f0b5 Mon Sep 17 00:00:00 2001
From: Juan Batiz-Benet <juan@benet.ai>
Date: Tue, 23 Dec 2014 23:12:22 -0800
Subject: [PATCH] dht/dht_test: bootstrap synchronously. fares better.

---
 routing/dht/dht.go      | 32 +++++++++++++-------------------
 routing/dht/dht_test.go | 39 ++++++++++++++++++++++++---------------
 2 files changed, 37 insertions(+), 34 deletions(-)

diff --git a/routing/dht/dht.go b/routing/dht/dht.go
index fdb5170f7..4cbf68e43 100644
--- a/routing/dht/dht.go
+++ b/routing/dht/dht.go
@@ -365,26 +365,20 @@ func (dht *IpfsDHT) PingRoutine(t time.Duration) {
 }
 
 // Bootstrap builds up list of peers by requesting random peer IDs
-func (dht *IpfsDHT) Bootstrap(ctx context.Context) {
+func (dht *IpfsDHT) Bootstrap(ctx context.Context, queries int) {
 
-	var wg sync.WaitGroup
+	// bootstrap sequentially, as results will compound
 	for i := 0; i < NumBootstrapQueries; i++ {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
-
-			id := make([]byte, 16)
-			rand.Read(id)
-			pi, err := dht.FindPeer(ctx, peer.ID(id))
-			if err == routing.ErrNotFound {
-				// this isn't an error. this is precisely what we expect.
-			} else if err != nil {
-				log.Errorf("Bootstrap peer error: %s", err)
-			} else {
-				// woah, we got a peer under a random id? it _cannot_ be valid.
-				log.Errorf("dht seemingly found a peer at a random bootstrap id (%s)...", pi)
-			}
-		}()
+		id := make([]byte, 16)
+		rand.Read(id)
+		pi, err := dht.FindPeer(ctx, peer.ID(id))
+		if err == routing.ErrNotFound {
+			// this isn't an error. this is precisely what we expect.
+		} else if err != nil {
+			log.Errorf("Bootstrap peer error: %s", err)
+		} else {
+			// woah, we got a peer under a random id? it _cannot_ be valid.
+			log.Errorf("dht seemingly found a peer at a random bootstrap id (%s)...", pi)
+		}
 	}
-	wg.Wait()
 }
diff --git a/routing/dht/dht_test.go b/routing/dht/dht_test.go
index d3041f364..f37656c2e 100644
--- a/routing/dht/dht_test.go
+++ b/routing/dht/dht_test.go
@@ -93,24 +93,23 @@ func connect(t *testing.T, ctx context.Context, a, b *IpfsDHT) {
 
 func bootstrap(t *testing.T, ctx context.Context, dhts []*IpfsDHT) {
 
-	// try multiple rounds...
+	ctx, cancel := context.WithCancel(ctx)
+
 	rounds := 1
 	for i := 0; i < rounds; i++ {
 		fmt.Printf("bootstrapping round %d/%d\n", i, rounds)
 
-		var wg sync.WaitGroup
+		// tried async. sequential fares much better. compare:
+		// 100 async https://gist.github.com/jbenet/56d12f0578d5f34810b2
+		// 100 sync https://gist.github.com/jbenet/6c59e7c15426e48aaedd
+		// probably because results compound
 		for _, dht := range dhts {
-			wg.Add(1)
-			go func(i int) {
-				defer wg.Done()
-				<-time.After(time.Duration(i) * time.Millisecond) // stagger them to avoid overwhelming
-				fmt.Printf("bootstrapping round %d/%d -- %s\n", i, rounds, dht.self)
-				dht.Bootstrap(ctx)
-			}(i)
+			fmt.Printf("bootstrapping round %d/%d -- %s\n", i, rounds, dht.self)
+			dht.Bootstrap(ctx, 3)
 		}
-		wg.Wait()
-
 	}
+
+	cancel()
 }
 
 func TestPing(t *testing.T) {
@@ -260,7 +259,7 @@ func TestProvides(t *testing.T) {
 func TestBootstrap(t *testing.T) {
 	ctx := context.Background()
 
-	nDHTs := 40
+	nDHTs := 10
 	_, _, dhts := setupDHTS(ctx, nDHTs, t)
 	defer func() {
 		for i := 0; i < nDHTs; i++ {
@@ -275,7 +274,6 @@ func TestBootstrap(t *testing.T) {
 	}
 
 	<-time.After(100 * time.Millisecond)
-
 	t.Logf("bootstrapping them so they find each other", nDHTs)
 	ctxT, _ := context.WithTimeout(ctx, 5*time.Second)
 	bootstrap(t, ctxT, dhts)
@@ -308,8 +306,19 @@ func TestProvidesMany(t *testing.T) {
 		connect(t, ctx, dhts[i], dhts[(i+1)%len(dhts)])
 	}
 
+	<-time.After(100 * time.Millisecond)
 	t.Logf("bootstrapping them so they find each other", nDHTs)
-	bootstrap(t, ctx, dhts)
+	ctxT, _ := context.WithTimeout(ctx, 5*time.Second)
+	bootstrap(t, ctxT, dhts)
+
+	<-time.After(5 * time.Second)
+	// the routing tables should be full now. let's inspect them.
+	t.Logf("checking routing table of %d", nDHTs)
+	for _, dht := range dhts {
+		fmt.Printf("checking routing table of %s\n", dht.self)
+		dht.routingTable.Print()
+		fmt.Println("")
+	}
 
 	d := 0
 	for k, v := range testCaseValues {
@@ -341,7 +350,7 @@ func TestProvidesMany(t *testing.T) {
 
 	errchan := make(chan error)
 
-	ctxT, _ := context.WithTimeout(ctx, 5*time.Second)
+	ctxT, _ = context.WithTimeout(ctx, 5*time.Second)
 
 	var wg sync.WaitGroup
 	getProvider := func(dht *IpfsDHT, k u.Key) {