p2p/discover: use iterator based seeding, drop old protocol test

p2p/discover/database.go

@@ -9,8 +9,11 @@ import (
 	"os"
 	"time"
 
+	"github.com/ethereum/go-ethereum/logger"
+	"github.com/ethereum/go-ethereum/logger/glog"
 	"github.com/ethereum/go-ethereum/rlp"
 	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/iterator"
 	"github.com/syndtr/goleveldb/leveldb/storage"
 )
 
@@ -19,13 +22,13 @@ var nodeDBNilNodeID = NodeID{}
 
 // nodeDB stores all nodes we know about.
 type nodeDB struct {
-	lvl *leveldb.DB
+	lvl    *leveldb.DB       // Interface to the database itself
+	seeder iterator.Iterator // Iterator for fetching possible seed nodes
 }
 
 // Schema layout for the node database
 var (
 	nodeDBVersionKey = []byte("version") // Version of the database to flush if changes
-	nodeDBStartupKey = []byte("startup") // Time when the node discovery started (seed selection)
 	nodeDBItemPrefix = []byte("n:")      // Identifier to prefix node entries with
 
 	nodeDBDiscoverRoot = ":discover"
@@ -137,26 +140,16 @@ func (db *nodeDB) storeInt64(key []byte, n int64) error {
 	return db.lvl.Put(key, blob, nil)
 }
 
-// startup retrieves the time instance when the bootstrapping last begun. Its
-// purpose is to prevent contacting potential seed nodes multiple times in the
-// same boot cycle.
-func (db *nodeDB) startup() time.Time {
-	return time.Unix(db.fetchInt64(nodeDBStartupKey), 0)
-}
-
-// updateStartup updates the bootstrap initiation time to the one specified.
-func (db *nodeDB) updateStartup(instance time.Time) error {
-	return db.storeInt64(nodeDBStartupKey, instance.Unix())
-}
-
 // node retrieves a node with a given id from the database.
 func (db *nodeDB) node(id NodeID) *Node {
 	blob, err := db.lvl.Get(makeKey(id, nodeDBDiscoverRoot), nil)
 	if err != nil {
+		glog.V(logger.Warn).Infof("failed to retrieve node: %v", err)
 		return nil
 	}
 	node := new(Node)
 	if err := rlp.DecodeBytes(blob, node); err != nil {
+		glog.V(logger.Warn).Infof("failed to decode node RLP: %v", err)
 		return nil
 	}
 	return node
@@ -203,34 +196,35 @@ func (db *nodeDB) updateLastPong(id NodeID, instance time.Time) error {
 // If the database runs out of potential seeds, we restart the startup counter
 // and start iterating over the peers again.
 func (db *nodeDB) querySeeds(n int) []*Node {
-	startup := db.startup()
-
-	it := db.lvl.NewIterator(nil, nil)
-	defer it.Release()
-
+	// Create a new seed iterator if none exists
+	if db.seeder == nil {
+		db.seeder = db.lvl.NewIterator(nil, nil)
+	}
+	// Iterate over the nodes and find suitable seeds
 	nodes := make([]*Node, 0, n)
-	for len(nodes) < n && it.Next() {
+	for len(nodes) < n && db.seeder.Next() {
 		// Iterate until a discovery node is found
-		id, field := splitKey(it.Key())
+		id, field := splitKey(db.seeder.Key())
 		if field != nodeDBDiscoverRoot {
 			continue
 		}
-		// Retrieve the last ping time, and if older than startup, query
-		lastPing := db.lastPing(id)
-		if lastPing.Before(startup) {
+		// Load it as a potential seed
 		if node := db.node(id); node != nil {
 			nodes = append(nodes, node)
 		}
 	}
-	}
-	// Reset the startup time if no seeds were found
+	// Release the iterator if we reached the end
 	if len(nodes) == 0 {
-		db.updateStartup(time.Now())
+		db.seeder.Release()
+		db.seeder = nil
 	}
 	return nodes
 }
 
 // close flushes and closes the database files.
 func (db *nodeDB) close() {
+	if db.seeder != nil {
+		db.seeder.Release()
+	}
 	db.lvl.Close()
 }

p2p/discover/database_test.go

@@ -84,22 +84,11 @@ func TestNodeDBFetchStore(t *testing.T) {
 	node := &Node{
 		ID:      MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
 		IP:      net.IP([]byte{192, 168, 0, 1}),
-		DiscPort: 31313,
 		TCPPort: 30303,
 	}
 	inst := time.Now()
 	db, _ := newNodeDB("")
 
-	// Check fetch/store operations on the startup object
-	if stored := db.startup(); stored.Unix() != 0 {
-		t.Errorf("startup: non-existing object: %v", stored)
-	}
-	if err := db.updateStartup(inst); err != nil {
-		t.Errorf("startup: failed to update: %v", err)
-	}
-	if stored := db.startup(); stored.Unix() != inst.Unix() {
-		t.Errorf("startup: value mismatch: have %v, want %v", stored, inst)
-	}
 	// Check fetch/store operations on a node ping object
 	if stored := db.lastPing(node.ID); stored.Unix() != 0 {
 		t.Errorf("ping: non-existing object: %v", stored)
@@ -129,8 +118,98 @@ func TestNodeDBFetchStore(t *testing.T) {
 	}
 	if stored := db.node(node.ID); stored == nil {
 		t.Errorf("node: not found")
-	} else if !bytes.Equal(stored.ID[:], node.ID[:]) || !bytes.Equal(stored.IP, node.IP) ||
-		stored.DiscPort != node.DiscPort || stored.TCPPort != node.TCPPort {
+	} else if !bytes.Equal(stored.ID[:], node.ID[:]) || !stored.IP.Equal(node.IP) || stored.TCPPort != node.TCPPort {
 		t.Errorf("node: data mismatch: have %v, want %v", stored, node)
 	}
 }
+
+var nodeDBSeedQueryNodes = []struct {
+	node Node
+	pong time.Time
+}{
+	{
+		node: Node{
+			ID: MustHexID("0x01d9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+			IP: []byte{127, 0, 0, 1},
+		},
+		pong: time.Now().Add(-2 * time.Second),
+	},
+	{
+		node: Node{
+			ID: MustHexID("0x02d9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+			IP: []byte{127, 0, 0, 2},
+		},
+		pong: time.Now().Add(-3 * time.Second),
+	},
+	{
+		node: Node{
+			ID: MustHexID("0x03d9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+			IP: []byte{127, 0, 0, 3},
+		},
+		pong: time.Now().Add(-1 * time.Second),
+	},
+}
+
+func TestNodeDBSeedQuery(t *testing.T) {
+	db, _ := newNodeDB("")
+
+	// Insert a batch of nodes for querying
+	for i, seed := range nodeDBSeedQueryNodes {
+		if err := db.updateNode(&seed.node); err != nil {
+			t.Fatalf("node %d: failed to insert: %v", i, err)
+		}
+	}
+	// Retrieve the entire batch and check for duplicates
+	seeds := db.querySeeds(2 * len(nodeDBSeedQueryNodes))
+	if len(seeds) != len(nodeDBSeedQueryNodes) {
+		t.Errorf("seed count mismatch: have %v, want %v", len(seeds), len(nodeDBSeedQueryNodes))
+	}
+	have := make(map[NodeID]struct{})
+	for _, seed := range seeds {
+		have[seed.ID] = struct{}{}
+	}
+	want := make(map[NodeID]struct{})
+	for _, seed := range nodeDBSeedQueryNodes {
+		want[seed.node.ID] = struct{}{}
+	}
+	for id, _ := range have {
+		if _, ok := want[id]; !ok {
+			t.Errorf("extra seed: %v", id)
+		}
+	}
+	for id, _ := range want {
+		if _, ok := have[id]; !ok {
+			t.Errorf("missing seed: %v", id)
+		}
+	}
+	// Make sure the next batch is empty (seed EOF)
+	seeds = db.querySeeds(2 * len(nodeDBSeedQueryNodes))
+	if len(seeds) != 0 {
+		t.Errorf("seed count mismatch: have %v, want %v", len(seeds), 0)
+	}
+}
+
+func TestNodeDBSeedQueryContinuation(t *testing.T) {
+	db, _ := newNodeDB("")
+
+	// Insert a batch of nodes for querying
+	for i, seed := range nodeDBSeedQueryNodes {
+		if err := db.updateNode(&seed.node); err != nil {
+			t.Fatalf("node %d: failed to insert: %v", i, err)
+		}
+	}
+	// Iteratively retrieve the batch, checking for an empty batch on reset
+	for i := 0; i < len(nodeDBSeedQueryNodes); i++ {
+		if seeds := db.querySeeds(1); len(seeds) != 1 {
+			t.Errorf("1st iteration %d: seed count mismatch: have %v, want %v", i, len(seeds), 1)
+		}
+	}
+	if seeds := db.querySeeds(1); len(seeds) != 0 {
+		t.Errorf("reset: seed count mismatch: have %v, want %v", len(seeds), 0)
+	}
+	for i := 0; i < len(nodeDBSeedQueryNodes); i++ {
+		if seeds := db.querySeeds(1); len(seeds) != 1 {
+			t.Errorf("2nd iteration %d: seed count mismatch: have %v, want %v", i, len(seeds), 1)
+		}
+	}
+}