From b04f712773458c5856a4b28ed725662b2510296a Mon Sep 17 00:00:00 2001
From: Evgenii Stratonikov <evgeniy@nspcc.ru>
Date: Sat, 28 May 2022 12:27:55 +0300
Subject: [PATCH] [#1446] services/tree: Cache connections to the container
 nodes

Signed-off-by: Evgenii Stratonikov <evgeniy@nspcc.ru>
---
 pkg/services/tree/cache.go      | 63 +++++++++++++++++++++++++++++++++
 pkg/services/tree/redirect.go   | 17 +--------
 pkg/services/tree/replicator.go |  2 +-
 pkg/services/tree/service.go    |  5 ++-
 4 files changed, 69 insertions(+), 18 deletions(-)
 create mode 100644 pkg/services/tree/cache.go

diff --git a/pkg/services/tree/cache.go b/pkg/services/tree/cache.go
new file mode 100644
index 000000000..db954d90d
--- /dev/null
+++ b/pkg/services/tree/cache.go
@@ -0,0 +1,63 @@
+package tree
+
+import (
+	"context"
+	"sync"
+
+	"github.com/hashicorp/golang-lru/simplelru"
+	"github.com/nspcc-dev/neofs-node/pkg/network"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/connectivity"
+)
+
+type clientCache struct {
+	sync.Mutex
+	simplelru.LRU
+}
+
+const defaultClientCacheSize = 10
+
+func (c *clientCache) init() {
+	l, _ := simplelru.NewLRU(defaultClientCacheSize, func(key, value interface{}) {
+		_ = value.(*grpc.ClientConn).Close()
+	})
+	c.LRU = *l
+}
+
+func (c *clientCache) get(ctx context.Context, netmapAddr string) (TreeServiceClient, error) {
+	c.Lock()
+	ccInt, ok := c.LRU.Get(netmapAddr)
+	c.Unlock()
+
+	if ok {
+		cc := ccInt.(*grpc.ClientConn)
+		if s := cc.GetState(); s == connectivity.Idle || s == connectivity.Ready {
+			return NewTreeServiceClient(cc), nil
+		}
+		_ = cc.Close()
+	}
+
+	cc, err := dialTreeService(ctx, netmapAddr)
+	if err != nil {
+		return nil, err
+	}
+
+	c.Lock()
+	c.LRU.Add(netmapAddr, cc)
+	c.Unlock()
+
+	return NewTreeServiceClient(cc), nil
+}
+
+func dialTreeService(ctx context.Context, netmapAddr string) (*grpc.ClientConn, error) {
+	var netAddr network.Address
+	if err := netAddr.FromString(netmapAddr); err != nil {
+		return nil, err
+	}
+
+	cc, err := grpc.DialContext(ctx, netAddr.URIAddr(), grpc.WithInsecure())
+	if err != nil {
+		return nil, err
+	}
+	return cc, nil
+}
diff --git a/pkg/services/tree/redirect.go b/pkg/services/tree/redirect.go
index 304ed0d7d..52348fb07 100644
--- a/pkg/services/tree/redirect.go
+++ b/pkg/services/tree/redirect.go
@@ -5,10 +5,8 @@ import (
 	"context"
 	"errors"
 
-	"github.com/nspcc-dev/neofs-node/pkg/network"
 	netmapSDK "github.com/nspcc-dev/neofs-sdk-go/netmap"
 	"go.uber.org/zap"
-	"google.golang.org/grpc"
 )
 
 var errNoSuitableNode = errors.New("no node was found to execute the request")
@@ -26,7 +24,7 @@ func (s *Service) forEachNode(ctx context.Context, cntNodes []netmapSDK.NodeInfo
 	for _, n := range cntNodes {
 		var stop bool
 		n.IterateNetworkEndpoints(func(endpoint string) bool {
-			c, err := dialTreeService(ctx, endpoint)
+			c, err := s.cache.get(ctx, endpoint)
 			if err != nil {
 				return false
 			}
@@ -45,16 +43,3 @@ func (s *Service) forEachNode(ctx context.Context, cntNodes []netmapSDK.NodeInfo
 	}
 	return nil
 }
-
-func dialTreeService(ctx context.Context, netmapAddr string) (TreeServiceClient, error) {
-	var netAddr network.Address
-	if err := netAddr.FromString(netmapAddr); err != nil {
-		return nil, err
-	}
-
-	cc, err := grpc.DialContext(ctx, netAddr.URIAddr(), grpc.WithInsecure())
-	if err != nil {
-		return nil, err
-	}
-	return NewTreeServiceClient(cc), nil
-}
diff --git a/pkg/services/tree/replicator.go b/pkg/services/tree/replicator.go
index 15ef0b032..313f12db7 100644
--- a/pkg/services/tree/replicator.go
+++ b/pkg/services/tree/replicator.go
@@ -70,7 +70,7 @@ func (s *Service) replicate(ctx context.Context, op movePair) error {
 		n.IterateNetworkEndpoints(func(addr string) bool {
 			lastAddr = addr
 
-			c, err := dialTreeService(ctx, addr)
+			c, err := s.cache.get(ctx, addr)
 			if err != nil {
 				lastErr = err
 				return false
diff --git a/pkg/services/tree/service.go b/pkg/services/tree/service.go
index b0d86ce10..af09d6063 100644
--- a/pkg/services/tree/service.go
+++ b/pkg/services/tree/service.go
@@ -18,6 +18,7 @@ import (
 type Service struct {
 	cfg
 
+	cache       clientCache
 	replicateCh chan movePair
 	closeCh     chan struct{}
 }
@@ -38,6 +39,7 @@ func New(opts ...Option) *Service {
 		s.log = zap.NewNop()
 	}
 
+	s.cache.init()
 	s.closeCh = make(chan struct{})
 	s.replicateCh = make(chan movePair, defaultReplicatorCapacity)
 
@@ -424,7 +426,8 @@ func (s *Service) Apply(_ context.Context, req *ApplyRequest) (*ApplyResponse, e
 	}
 
 	d := pilorama.CIDDescriptor{CID: cid, Position: pos, Size: size}
-	return nil, s.forest.TreeApply(d, req.GetBody().GetTreeId(), &pilorama.Move{
+	resp := &ApplyResponse{Body: &ApplyResponse_Body{}, Signature: &Signature{}}
+	return resp, s.forest.TreeApply(d, req.GetBody().GetTreeId(), &pilorama.Move{
 		Parent: op.GetParentId(),
 		Child:  op.GetChildId(),
 		Meta:   meta,