1. Expire non-provider records older than MaxAge

2. Original publisher shoulld republish putvalue records

dht.go

@@ -100,6 +100,11 @@ func New(ctx context.Context, h host.Host, options ...opts.Option) (*IpfsDHT, er
 	dht.proc.AddChild(dht.providers.Process())
 	dht.Validator = cfg.Validator
 
+	// proc to expire putValue records
+	recordExpiryProc := goprocessctx.WithContext(ctx)
+	recordExpiryProc.Go(dht.expireNonProviderRecords)
+	dht.proc.AddChild(recordExpiryProc)
+
 	if !cfg.Client {
 		for _, p := range cfg.Protocols {
 			h.SetStreamHandler(p, dht.handleNewStream)

go.mod

@@ -21,6 +21,7 @@ require (
 	github.com/mr-tron/base58 v1.1.2
 	github.com/multiformats/go-multiaddr v0.0.4
 	github.com/multiformats/go-multiaddr-dns v0.0.2
+	github.com/multiformats/go-multihash v0.0.5
 	github.com/multiformats/go-multistream v0.1.0
 	github.com/stretchr/testify v1.3.0
 	github.com/whyrusleeping/base32 v0.0.0-20170828182744-c30ac30633cc

handlers.go

@@ -121,7 +121,7 @@ func (dht *IpfsDHT) checkLocalDatastore(k []byte) (*recpb.Record, error) {
 		recordIsBad = true
 	}
 
-	if time.Since(recvtime) > MaxRecordAge {
+	if time.Since(recvtime) > maxNonProviderRecordAge {
 		logger.Debug("old record found, tossing.")
 		recordIsBad = true
 	}

providers/providers.go

@@ -74,10 +74,11 @@ func NewProviderManager(ctx context.Context, local peer.ID, dstore ds.Batching)
 	return pm
 }
 
-const providersKeyPrefix = "/providers/"
+// prefix to be used for all provider record keys
+const ProvidersKeyPrefix = "/providers/"
 
 func mkProvKey(k cid.Cid) string {
-	return providersKeyPrefix + base32.RawStdEncoding.EncodeToString(k.Bytes())
+	return ProvidersKeyPrefix + base32.RawStdEncoding.EncodeToString(k.Bytes())
 }
 
 func (pm *ProviderManager) Process() goprocess.Process {
@@ -284,7 +285,7 @@ func (pm *ProviderManager) run(proc goprocess.Process) {
 
 			// Now, kick off a GC of the datastore.
 			q, err := pm.dstore.Query(dsq.Query{
-				Prefix: providersKeyPrefix,
+				Prefix: ProvidersKeyPrefix,
 			})
 			if err != nil {
 				log.Error("provider record GC query failed: ", err)

providers/providers_test.go

@@ -185,7 +185,7 @@ func TestProvidesExpire(t *testing.T) {
 		t.Fatal("providers map not cleaned up")
 	}
 
-	res, err := ds.Query(dsq.Query{Prefix: providersKeyPrefix})
+	res, err := ds.Query(dsq.Query{Prefix: ProvidersKeyPrefix})
 	if err != nil {
 		t.Fatal(err)
 	}

records.go

@@ -3,21 +3,30 @@ package dht
 import (
 	"context"
 	"fmt"
+	"strings"
 	"time"
 
+	"github.com/gogo/protobuf/proto"
+	ds "github.com/ipfs/go-datastore"
+	"github.com/ipfs/go-datastore/query"
+	u "github.com/ipfs/go-ipfs-util"
+	"github.com/jbenet/goprocess"
+	ci "github.com/libp2p/go-libp2p-core/crypto"
 	"github.com/libp2p/go-libp2p-core/peer"
 	"github.com/libp2p/go-libp2p-core/routing"
-
-	ci "github.com/libp2p/go-libp2p-core/crypto"
+	"github.com/libp2p/go-libp2p-kad-dht/providers"
+	recpb "github.com/libp2p/go-libp2p-record/pb"
 )
 
-// MaxRecordAge specifies the maximum time that any node will hold onto a record
+// maxNonProviderRecordAge specifies the maximum time that any node will hold onto a record
 // from the time its received. This does not apply to any other forms of validity that
 // the record may contain.
 // For example, a record may contain an ipns entry with an EOL saying its valid
 // until the year 2020 (a great time in the future). For that record to stick around
-// it must be rebroadcasted more frequently than once every 'MaxRecordAge'
-const MaxRecordAge = time.Hour * 36
+// it must be rebroadcasted more frequently than once every 'maxNonProviderRecordAge'
+var maxNonProviderRecordAge = time.Hour * 12
+
+var defaultRecordsSweepInterval = time.Hour * 1
 
 type pubkrs struct {
 	pubk ci.PubKey
@@ -135,3 +144,58 @@ func (dht *IpfsDHT) getPublicKeyFromNode(ctx context.Context, p peer.ID) (ci.Pub
 	logger.Debugf("Got public key from node %v itself", p)
 	return pubk, nil
 }
+
+func (dht *IpfsDHT) expireNonProviderRecords(proc goprocess.Process) {
+	for {
+		select {
+		case <-proc.Closing():
+			return
+		case <-time.After(defaultRecordsSweepInterval):
+		}
+
+		res, err := dht.datastore.Query(query.Query{Filters: []query.Filter{&expireRecordFilter{}}})
+		if err != nil {
+			logger.Errorf("expire records proc: failed to run query against datastore, error is %+v", err)
+			continue
+		}
+
+		for {
+			e, ok := res.NextSync()
+			if !ok {
+				break
+			}
+			if err := dht.datastore.Delete(ds.RawKey(e.Key)); err != nil {
+				logger.Errorf("expire records proc: failed to delete key %s from datastore, error is %+v", e.Key, err)
+			}
+		}
+	}
+}
+
+type expireRecordFilter struct{}
+
+func (f *expireRecordFilter) Filter(e query.Entry) bool {
+	// unmarshal record
+	rec := new(recpb.Record)
+	if err := proto.Unmarshal(e.Value, rec); err != nil {
+		logger.Debugf("expire records filter: failed to unmarshal DHT record from datastore, error is %+v", err)
+		return false
+	}
+
+	// should not be a provider record
+	if strings.HasPrefix(e.Key, providers.ProvidersKeyPrefix) {
+		return false
+	}
+
+	// age should be greater than maxNonProviderRecordAge
+	t, err := u.ParseRFC3339(rec.TimeReceived)
+	if err != nil {
+		logger.Debugf("expire records filter: failed to parse time in DHT record, error is %+v", err)
+		return false
+	}
+
+	if time.Since(t) > maxNonProviderRecordAge {
+		return true
+	}
+
+	return false
+}

records_test.go

@@ -3,16 +3,22 @@ package dht
 import (
 	"context"
 	"crypto/rand"
-	"github.com/libp2p/go-libp2p-core/test"
 	"testing"
 	"time"
 
+	"github.com/ipfs/go-cid"
+	"github.com/libp2p/go-libp2p-core/test"
+	"github.com/multiformats/go-multihash"
+	"github.com/stretchr/testify/assert"
+
+	ds "github.com/ipfs/go-datastore"
 	u "github.com/ipfs/go-ipfs-util"
 	ci "github.com/libp2p/go-libp2p-core/crypto"
 	"github.com/libp2p/go-libp2p-core/peer"
 	"github.com/libp2p/go-libp2p-core/routing"
-	record "github.com/libp2p/go-libp2p-record"
-	tnet "github.com/libp2p/go-libp2p-testing/net"
+	pb "github.com/libp2p/go-libp2p-kad-dht/pb"
+	"github.com/libp2p/go-libp2p-record"
+	"github.com/libp2p/go-libp2p-testing/net"
 )
 
 // Check that GetPublicKey() correctly extracts a public key
@@ -305,3 +311,97 @@ func TestPubkeyGoodKeyFromDHTGoodKeyDirect(t *testing.T) {
 		t.Fatal("got incorrect public key")
 	}
 }
+
+func TestExpireNonProviderRecords(t *testing.T) {
+	sVal := defaultRecordsSweepInterval
+	defer func() { defaultRecordsSweepInterval = sVal }()
+
+	defaultRecordsSweepInterval = 20 * time.Millisecond
+
+	// create dht
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	d := setupDHT(ctx, t, false)
+
+	putRecord := func(key string, value []byte) error {
+		rec := record.MakePutRecord(key, value)
+		pmes := pb.NewMessage(pb.Message_PUT_VALUE, rec.Key, 0)
+		pmes.Record = rec
+		_, err := d.handlePutValue(ctx, "testpeer", pmes)
+		return err
+	}
+
+	addProv := func(c cid.Cid) error {
+		msg, err := d.makeProvRecord(c)
+		pi := peer.AddrInfo{
+			ID:    "testpeer",
+			Addrs: d.host.Addrs(),
+		}
+		msg.ProviderPeers = pb.RawPeerInfosToPBPeers([]peer.AddrInfo{pi})
+		assert.NoError(t, err)
+
+		_, err = d.handleAddProvider(ctx, "testpeer", msg)
+		return err
+	}
+
+	getProv := func(c cid.Cid) (*pb.Message, error) {
+		pmes := pb.NewMessage(pb.Message_GET_PROVIDERS, c.Bytes(), 0)
+		m, err := d.handleGetProviders(ctx, "test peer", pmes)
+		return m, err
+	}
+
+	// put non-provider record 1 with current time
+	key1 := "/v/key1"
+	value1 := []byte("v1")
+	assert.NoError(t, putRecord(key1, value1))
+
+	// put non-provider record 2 with current time
+	key2 := "/v/key2"
+	value2 := []byte("v2")
+	assert.NoError(t, putRecord(key2, value2))
+
+	// add provider with current time
+	mh, err := multihash.Sum([]byte("data"), multihash.SHA2_256, -1)
+	assert.NoError(t, err)
+	c := cid.NewCidV0(mh)
+	assert.NoError(t, addProv(c))
+
+	// sweep will not delete any of them
+	time.Sleep(100 * time.Millisecond)
+
+	// get & verify all are present
+
+	// we need to check the datastore for non-provider records to test the expiry Proc
+	// because a side-effect of handle get value is also that it deletes records which are beyond MaxAge
+	// & we do not want to hit that path
+	_, err = d.datastore.Get(convertToDsKey([]byte(key1)))
+	assert.NoError(t, err)
+
+	_, err = d.datastore.Get(convertToDsKey([]byte(key2)))
+	assert.NoError(t, err)
+
+	// ensure provider record is still available
+	m, err := getProv(c)
+	assert.NoError(t, err)
+	assert.NotEmpty(t, m.ProviderPeers)
+
+	// change max age to 100 millisecond
+	mVal := maxNonProviderRecordAge
+	maxNonProviderRecordAge = 100 * time.Millisecond
+	defer func() { maxNonProviderRecordAge = mVal }()
+
+	// sweep will remove non-provider both records now
+	time.Sleep(100 * time.Millisecond)
+
+	// verify both non-provider records are absent
+	_, err = d.datastore.Get(convertToDsKey([]byte(key1)))
+	assert.Equal(t, ds.ErrNotFound, err)
+
+	_, err = d.datastore.Get(convertToDsKey([]byte(key2)))
+	assert.Equal(t, ds.ErrNotFound, err)
+
+	// but, provider record will still be available
+	m, err = getProv(c)
+	assert.NoError(t, err)
+	assert.NotEmpty(t, m.ProviderPeers)
+}

routing.go

@@ -27,6 +27,8 @@ import (
 // results will wait for the channel to drain.
 var asyncQueryBuffer = 10
 
+var putValueRepublishInterval = 6 * time.Hour
+
 // This file implements the Routing interface for the IpfsDHT struct.
 
 // Basic Put/Get
@@ -98,6 +100,28 @@ func (dht *IpfsDHT) PutValue(ctx context.Context, key string, value []byte, opts
 		}(p)
 	}
 	wg.Wait()
+
+	// original publisher should keep re-publishing the record because the network isn't `steady`/`stable`
+	// and the K closet peers we just published to can become unavailable / no longer be the K closet
+	go func() {
+		for {
+			select {
+			case <-dht.proc.Closing():
+				return
+			case <-time.After(putValueRepublishInterval):
+				// TODO:We can not re-use the original context here as it may have expired
+				// But, is it fair to use this one ?
+				ctx, cancel := context.WithTimeout(context.Background(), 5*time.Minute)
+				if err := dht.PutValue(ctx, key, value, opts...); err != nil {
+					logger.Errorf("putValue republish proc: failed to republish key %s, error is %+v", key, err)
+				} else {
+					logger.Debugf("putValue republish proc: successfully republished key %s", key)
+				}
+				cancel()
+			}
+		}
+	}()
+
 	return nil
 }