From df903ea2153f74760f3dad7c43c33ea0d42b04da Mon Sep 17 00:00:00 2001
From: Dylan Lott <dylan@storj.io>
Date: Mon, 28 Jan 2019 12:36:20 -0700
Subject: [PATCH] Decreases refresh time per bucket in Kademlia (#1150)

---
 pkg/kademlia/kademlia.go      | 15 +++++++++++----
 pkg/kademlia/kademlia_test.go |  4 ++--
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/pkg/kademlia/kademlia.go b/pkg/kademlia/kademlia.go
index 829efaa86..be71a42e9 100644
--- a/pkg/kademlia/kademlia.go
+++ b/pkg/kademlia/kademlia.go
@@ -221,8 +221,15 @@ func (k *Kademlia) Bootstrap(ctx context.Context) error {
 	k.routingTable.mutex.Lock()
 	id := k.routingTable.self.Id
 	k.routingTable.mutex.Unlock()
-
 	_, err = k.lookup(ctx, id, true)
+
+	// TODO(dylan): We do not currently handle this last bit of behavior.
+	// ```
+	// Finally, u refreshes all k-buckets further away than its closest neighbor.
+	// During the refreshes, u both populates its own k-buckets and inserts
+	// itself into other nodes' k-buckets as necessary.
+	// ``
+
 	return err
 }
 
@@ -338,7 +345,7 @@ func (k *Kademlia) RunRefresh(ctx context.Context) error {
 
 	ticker := time.NewTicker(5 * time.Minute)
 	for {
-		if err := k.refresh(ctx); err != nil {
+		if err := k.refresh(ctx, time.Minute); err != nil {
 			k.log.Warn("bucket refresh failed", zap.Error(err))
 		}
 		select {
@@ -351,7 +358,7 @@ func (k *Kademlia) RunRefresh(ctx context.Context) error {
 }
 
 // refresh updates each Kademlia bucket not contacted in the last hour
-func (k *Kademlia) refresh(ctx context.Context) error {
+func (k *Kademlia) refresh(ctx context.Context, threshold time.Duration) error {
 	bIDs, err := k.routingTable.GetBucketIds()
 	if err != nil {
 		return Error.Wrap(err)
@@ -363,7 +370,7 @@ func (k *Kademlia) refresh(ctx context.Context) error {
 		ts, tErr := k.routingTable.GetBucketTimestamp(bID)
 		if tErr != nil {
 			errors.Add(tErr)
-		} else if now.After(ts.Add(time.Hour)) {
+		} else if now.After(ts.Add(threshold)) {
 			rID, _ := randomIDInRange(startID, keyToBucketID(bID))
 			_, _ = k.FindNode(ctx, rID) // ignore node not found
 		}
diff --git a/pkg/kademlia/kademlia_test.go b/pkg/kademlia/kademlia_test.go
index 01189995f..362778b2a 100644
--- a/pkg/kademlia/kademlia_test.go
+++ b/pkg/kademlia/kademlia_test.go
@@ -205,13 +205,13 @@ func TestRefresh(t *testing.T) {
 	err := rt.SetBucketTimestamp(bID[:], now.Add(-2*time.Hour))
 	assert.NoError(t, err)
 	//refresh should  call FindNode, updating the time
-	err = k.refresh(ctx)
+	err = k.refresh(ctx, time.Minute)
 	assert.NoError(t, err)
 	ts1, err := rt.GetBucketTimestamp(bID[:])
 	assert.NoError(t, err)
 	assert.True(t, now.Add(-5*time.Minute).Before(ts1))
 	//refresh should not call FindNode, leaving the previous time
-	err = k.refresh(ctx)
+	err = k.refresh(ctx, time.Minute)
 	assert.NoError(t, err)
 	ts2, err := rt.GetBucketTimestamp(bID[:])
 	assert.NoError(t, err)