fix:can't switch sync mode when no snap-sync peer

config/config.go

@@ -144,6 +144,8 @@ type Config struct {
 
 	// TODO: It will soon be discarded in the near future
 	DevSnapSync bool `long:"devsnapsync" description:"Enable snap sync for P2P that only exist in development mode"`
+
+	SnapTimeout int `long:"snaptimeout" description:"Unable to find a peer that supports snap-sync service for setting IBD timeout(seconds), it will switch to the normal sync method"`
 }
 
 func (c *Config) GetMinningAddrs() []types.Address {

p2p/peers/interface.go

@@ -40,6 +40,7 @@ type P2P interface {
 	IsRunning() bool
 	Consensus() model.Consensus
 	MeerServer() *p2p.QngServer
+	IsSnap() bool
 }
 
 type P2PRPC interface {

p2p/synch/snapsync.go

@@ -9,7 +9,6 @@ import (
 	"github.com/Qitmeer/qng/core/blockchain/utxo"
 	"github.com/Qitmeer/qng/core/event"
 	"github.com/Qitmeer/qng/core/json"
-	"github.com/Qitmeer/qng/core/protocol"
 	"github.com/Qitmeer/qng/core/types"
 	"github.com/Qitmeer/qng/meerdag"
 	"github.com/Qitmeer/qng/p2p/common"
@@ -83,8 +82,7 @@ func (ps *PeerSync) GetSnapSyncInfo() *json.SnapSyncInfo {
 }
 
 func (ps *PeerSync) startSnapSync() bool {
-	snap := protocol.HasServices(ps.sy.p2p.Config().Services, protocol.Snap)
-	if !snap {
+	if !ps.sy.p2p.IsSnap() {
 		if ps.IsSnapSync() {
 			log.Error("There is an unfinished snap-sync, please enable the snap service")
 		}
@@ -105,8 +103,11 @@ func (ps *PeerSync) startSnapSync() bool {
 		return false
 	}
 	if !isValidSnapPeer(bestPeer) {
-		snapPeer := ps.getSnapSyncPeer()
+		snapPeer, change := ps.getSnapSyncPeer(ps.sy.p2p.Consensus().Config().SnapTimeout)
 		if snapPeer == nil {
+			if change {
+				return false
+			}
 			return true
 		}
 		bestPeer = snapPeer
@@ -210,7 +211,7 @@ func (ps *PeerSync) continueSnapSync() bool {
 	log.Info("Continue snap-sync", "point", ps.snapStatus.syncPoint.GetHash().String(), "point_order", ps.snapStatus.GetSyncPoint().GetOrder(), "status", fmt.Sprintf("%v", ps.snapStatus.ToInfo()))
 
 	best := ps.Chain().BestSnapshot()
-	bestPeer := ps.getSnapSyncPeer()
+	bestPeer, _ := ps.getSnapSyncPeer(0)
 	if bestPeer == nil {
 		return true
 	}
@@ -291,7 +292,7 @@ func (ps *PeerSync) trySyncSnapStatus(pe *peers.Peer) *pb.SnapSyncRsp {
 			return ret
 		}
 		log.Warn("Try change snap peer")
-		newPeer := ps.getSnapSyncPeer()
+		newPeer, _ := ps.getSnapSyncPeer(0)
 		if newPeer == nil {
 			return nil
 		}
@@ -385,20 +386,25 @@ func (ps *PeerSync) processRsp(ssr *pb.SnapSyncRsp) ([]*blockchain.SnapData, err
 	return ret, nil
 }
 
-func (ps *PeerSync) getSnapSyncPeer() *peers.Peer {
+func (ps *PeerSync) getSnapSyncPeer(timeout int) (*peers.Peer, bool) {
 	start := time.Now()
 	var pe *peers.Peer
 	for pe == nil {
 		pe = ps.getBestPeer(true)
 		if pe == nil {
+			if timeout > 0 {
+				if time.Since(start) > time.Duration(timeout)*time.Second {
+					return nil, true
+				}
+			}
 			log.Debug("Try to get snap-sync peer", "cost", time.Since(start).String())
 			time.Sleep(SnapSyncReqInterval)
 		}
 		if !ps.IsRunning() {
-			return nil
+			return nil, false
 		}
 	}
-	return pe
+	return pe, false
 }
 
 func (s *Sync) sendSnapSyncRequest(stream network.Stream, pe *peers.Peer) (*pb.SnapSyncRsp, *common.Error) {

services/common/flags.go

@@ -650,6 +650,11 @@ var (
 			Usage:       "Generate (mine) coins using the CPU on develop mode whithout gap",
 			Destination: &cfg.GenerateNoDevGap,
 		},
+		&cli.IntFlag{
+			Name:        "snaptimeout",
+			Usage:       "Unable to find a peer that supports snap-sync service for setting IBD timeout(seconds), it will switch to the normal sync method",
+			Destination: &cfg.SnapTimeout,
+		},
 	}
 )
 
@@ -686,6 +691,7 @@ func DefaultConfig(homeDir string) *config.Config {
 		SubmitNoSynced:       false,
 		DevNextGDB:           true,
 		GBTTimeOut:           defaultGBTTimeout,
+		SnapTimeout:          300,
 	}
 	if len(homeDir) > 0 {
 		hd, err := filepath.Abs(homeDir)