[BUGFIX] add Health Check for Range over gRPC Connection Loop

internal/net/grpc/client.go

@@ -90,7 +90,7 @@
 	GetCallOption() []CallOption
 	GetBackoff() backoff.Backoff
 	SetDisableResolveDNSAddr(addr string, disabled bool)
-	ConnectedAddrs() []string
+	ConnectedAddrs(context.Context) []string
 	Close(ctx context.Context) error
 }
 
@@ -249,7 +249,7 @@
 				return ctx.Err()
 			case <-prTick.C:
 				if g.enablePoolRebalance {
-					err = g.rangeConns(func(addr string, p pool.Conn) bool {
+					err = g.rangeConns(ctx, func(addr string, p pool.Conn) bool {
 						// if addr or pool is nil or empty the registration of conns is invalid let's disconnect them
 						if addr == "" || p == nil {
 							disconnectTargets = append(disconnectTargets, addr)
@@ -286,7 +286,7 @@
 					})
 				}
 			case <-hcTick.C:
-				err = g.rangeConns(func(addr string, p pool.Conn) bool {
+				err = g.rangeConns(ctx, func(addr string, p pool.Conn) bool {
 					// if addr or pool is nil or empty the registration of conns is invalid let's disconnect them
 					if addr == "" || p == nil {
 						disconnectTargets = append(disconnectTargets, addr)
@@ -415,7 +415,7 @@
 	if g.conns.Len() == 0 {
 		return errors.ErrGRPCClientConnNotFound("*")
 	}
-	err = g.rangeConns(func(addr string, p pool.Conn) bool {
+	err = g.rangeConns(ctx, func(addr string, p pool.Conn) bool {
 		ssctx, sspan := trace.StartSpan(sctx, apiName+"/Client.Range/"+addr)
 		defer func() {
 			if sspan != nil {
@@ -478,7 +478,7 @@
 	if g.conns.Len() == 0 {
 		return errors.ErrGRPCClientConnNotFound("*")
 	}
-	err = g.rangeConns(func(addr string, p pool.Conn) bool {
+	err = g.rangeConns(ctx, func(addr string, p pool.Conn) bool {
 		eg.Go(safety.RecoverFunc(func() (err error) {
 			ssctx, sspan := trace.StartSpan(egctx, apiName+"/Client.RangeConcurrent/"+addr)
 			defer func() {
@@ -565,7 +565,7 @@
 			return nil
 		default:
 			p, ok := g.conns.Load(addr)
-			if !ok || p == nil {
+			if !ok || p == nil || !p.IsHealthy(sctx) {
 				g.crl.Store(addr, true)
 				log.Warnf("gRPCClient.OrderedRange operation failed, gRPC connection pool for %s is invalid,\terror: %v", addr, errors.ErrGRPCClientConnNotFound(addr))
 				continue
@@ -634,7 +634,7 @@
 		addr := order
 		eg.Go(safety.RecoverFunc(func() (err error) {
 			p, ok := g.conns.Load(addr)
-			if !ok || p == nil {
+			if !ok || p == nil || !p.IsHealthy(sctx) {
 				g.crl.Store(addr, true)
 				log.Warnf("gRPCClient.OrderedRangeConcurrent operation failed, gRPC connection pool for %s is invalid,\terror: %v", addr, errors.ErrGRPCClientConnNotFound(addr))
 				return nil
@@ -701,7 +701,7 @@
 	}
 
 	do := func() (data any, err error) {
-		cerr := g.rangeConns(func(addr string, p pool.Conn) bool {
+		cerr := g.rangeConns(ctx, func(addr string, p pool.Conn) bool {
 			select {
 			case <-ctx.Done():
 				err = ctx.Err()
@@ -879,14 +879,14 @@
 						errors.Is(err, context.DeadlineExceeded) {
 						return nil, false, err
 					}
-					return nil, err != nil, err
+					return nil, p.IsHealthy(ctx), err
 				}
 				status.Log(st.Code(), err)
 				switch st.Code() {
 				case codes.Internal,
 					codes.Unavailable,
 					codes.ResourceExhausted:
-					return nil, err != nil, err
+					return nil, p.IsHealthy(ctx), err
 				}
 				return nil, false, err
 			}
@@ -1066,7 +1066,7 @@
 		atomic.AddUint64(&g.clientCount, ^uint64(0))
 		if p != nil {
 			log.Debugf("gRPC client connection pool addr = %s will disconnect soon...", addr)
-			return nil, p.Disconnect()
+			return nil, p.Disconnect(ctx)
 		}
 		return nil, nil
 	})
@@ -1085,10 +1085,10 @@
 	return nil
 }
 
-func (g *gRPCClient) ConnectedAddrs() (addrs []string) {
+func (g *gRPCClient) ConnectedAddrs(ctx context.Context) (addrs []string) {
 	addrs = make([]string, 0, g.conns.Len())
-	err := g.rangeConns(func(addr string, p pool.Conn) bool {
-		if p != nil && p.IsHealthy(context.Background()) {
+	err := g.rangeConns(ctx, func(addr string, p pool.Conn) bool {
+		if p != nil && p.IsHealthy(ctx) {
 			addrs = append(addrs, addr)
 		}
 		return true
@@ -1104,18 +1104,34 @@
 		g.stopMonitor()
 	}
 	g.conns.Range(func(addr string, p pool.Conn) bool {
-		derr := g.Disconnect(ctx, addr)
-		if derr != nil && !errors.Is(derr, errors.ErrGRPCClientConnNotFound(addr)) {
-			err = errors.Join(err, derr)
+		select {
+		case <-ctx.Done():
+			return false
+		default:
+			derr := g.Disconnect(ctx, addr)
+			if derr != nil && !errors.Is(derr, errors.ErrGRPCClientConnNotFound(addr)) {
+				err = errors.Join(err, derr)
+			}
+			return true
 		}
-		return true
 	})
 	return err
 }
 
-func (g *gRPCClient) rangeConns(fn func(addr string, p pool.Conn) bool) error {
+func (g *gRPCClient) rangeConns(ctx context.Context, fn func(addr string, p pool.Conn) bool) error {
 	var cnt int
 	g.conns.Range(func(addr string, p pool.Conn) bool {
+		if p == nil || !p.IsHealthy(ctx) {
+			pc, err := p.Connect(ctx)
+			if pc == nil || err != nil || !pc.IsHealthy(ctx) {
+				if pc != nil {
+					pc.Disconnect(ctx)
+				}
+				log.Debugf("Unhealthy connection detected for %s during gRPC Connection Range over Loop:\t%s", addr, p.String())
+				return true
+			}
+			p = pc
+		}
 		cnt++
 		return fn(addr, p)
 	})

internal/net/grpc/client_test.go

@@ -3107,7 +3107,7 @@ package grpc
 // 				stopMonitor:            test.fields.stopMonitor,
 // 			}
 //
-// 			gotAddrs := g.ConnectedAddrs()
+// 			gotAddrs := g.ConnectedAddrs(context.Background)
 // 			if err := checkFunc(test.want, gotAddrs); err != nil {
 // 				tt.Errorf("error = %v", err)
 // 			}
@@ -3303,6 +3303,7 @@ package grpc
 //
 // func Test_gRPCClient_rangeConns(t *testing.T) {
 // 	type args struct {
+// 		ctx context.Context
 // 		fn func(addr string, p pool.Conn) bool
 // 	}
 // 	type fields struct {

internal/net/grpc/pool/pool.go

@@ -34,6 +34,7 @@
 	"github.com/vdaas/vald/internal/strings"
 	"github.com/vdaas/vald/internal/sync"
 	"github.com/vdaas/vald/internal/sync/errgroup"
+	"github.com/vdaas/vald/internal/sync/singleflight"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/connectivity"
 )
@@ -45,9 +46,9 @@
 
 type Conn interface {
 	Connect(context.Context) (Conn, error)
-	Disconnect() error
+	Disconnect(context.Context) error
 	Do(ctx context.Context, f func(*ClientConn) error) error
-	Get(ctx context.Context) (conn *ClientConn, ok bool)
+	Get(context.Context) (conn *ClientConn, ok bool)
 	IsHealthy(context.Context) bool
 	IsIPConn() bool
 	Len() uint64
@@ -72,6 +73,7 @@
 	current       atomic.Uint64
 	bo            backoff.Backoff
 	eg            errgroup.Group
+	group         singleflight.Group[Conn]
 	dopts         []DialOption
 	dialTimeout   time.Duration
 	roccd         time.Duration // reconnection old connection closing duration
@@ -94,6 +96,8 @@
 	p.init(true)
 	p.closing.Store(false)
 
+	p.group = singleflight.New[Conn]()
+
 	var (
 		isIPv4, isIPv6 bool
 		port           uint16
@@ -222,11 +226,11 @@
 		return
 	}
 	p.init(false)
-	p.pmu.RLock()
+	p.pmu.Lock()
 	if p.pool != nil && p.Size() > uint64(idx) && len(p.pool) > idx {
 		p.pool[idx].Store(pc)
 	}
-	p.pmu.RUnlock()
+	p.pmu.Unlock()
 }
 
 func (p *pool) loop(
@@ -335,7 +339,6 @@
 	if p == nil || p.closing.Load() {
 		return p, nil
 	}
-
 	p.init(false)
 
 	if p.isIP || !p.resolveDNS {
@@ -437,8 +440,7 @@
 	return p, nil
 }
 
-func (p *pool) Disconnect() (err error) {
-	ctx := context.Background()
+func (p *pool) Disconnect(ctx context.Context) (err error) {
 	p.closing.Store(true)
 	defer p.closing.Store(false)
 	emap := make(map[string]error, p.len())
@@ -572,40 +574,41 @@
 	if p == nil {
 		return errors.ErrGRPCClientConnNotFound("*")
 	}
-	idx, conn, ok := p.getHealthyConn(ctx, 0, p.Len())
-	if !ok || conn == nil {
+	idx, pc, ok := p.getHealthyConn(ctx, 0, p.Len())
+	if !ok || pc == nil || pc.conn == nil {
 		return errors.ErrGRPCClientConnNotFound(p.addr)
 	}
+	conn := pc.conn
 	err = f(conn)
 	if errors.Is(err, grpc.ErrClientConnClosing) {
 		if conn != nil {
 			if cerr := conn.Close(); cerr != nil && !errors.Is(cerr, grpc.ErrClientConnClosing) {
 				log.Warnf("Failed to close connection: %v", cerr)
 			}
 		}
-		conn, err = p.dial(ctx, p.addr)
-		if err == nil && conn != nil && isHealthy(ctx, conn) {
-			p.store(idx, &poolConn{
-				conn: conn,
-				addr: p.addr,
-			})
-			if newErr := f(conn); newErr != nil {
+		rerr := p.refreshConn(ctx, idx, pc, p.addr)
+		if rerr == nil {
+			if newErr := f(p.load(idx).conn); newErr != nil {
 				return errors.Join(err, newErr)
 			}
 			return nil
 		}
+		err = errors.Join(err, rerr)
 	}
 	return err
 }
 
 func (p *pool) Get(ctx context.Context) (conn *ClientConn, ok bool) {
-	_, conn, ok = p.getHealthyConn(ctx, 0, p.Len())
-	return conn, ok
+	_, pc, ok := p.getHealthyConn(ctx, 0, p.Len())
+	if ok && pc != nil {
+		return pc.conn, true
+	}
+	return nil, false
 }
 
 func (p *pool) getHealthyConn(
 	ctx context.Context, cnt, retry uint64,
-) (idx int, conn *ClientConn, ok bool) {
+) (idx int, pc *poolConn, ok bool) {
 	if p == nil || p.closing.Load() {
 		return 0, nil, false
 	}
@@ -618,33 +621,29 @@
 	if retry <= 0 || retry > math.MaxUint64-pl || pl <= 0 {
 		if p.isIP {
 			log.Warnf("failed to find gRPC IP connection pool for %s.\tlen(pool): %d,\tretried: %d,\tseems IP %s is unhealthy will going to disconnect...", p.addr, pl, cnt, p.addr)
-			if err := p.Disconnect(); err != nil {
+			if err := p.Disconnect(ctx); err != nil {
 				log.Debugf("failed to disconnect gRPC IP direct connection for %s,\terr: %v", p.addr, err)
 			}
 			return 0, nil, false
 		}
 		if pl > 0 {
 			idx = int(p.current.Add(1) % pl)
 		}
-		if pc := p.load(idx); pc != nil && isHealthy(ctx, pc.conn) {
-			return idx, pc.conn, true
+		if pc = p.load(idx); pc != nil && isHealthy(ctx, pc.conn) {
+			return idx, pc, true
 		}
-		conn, err := p.dial(ctx, p.addr)
-		if err == nil && conn != nil && isHealthy(ctx, conn) {
-			p.store(idx, &poolConn{
-				conn: conn,
-				addr: p.addr,
-			})
-			return idx, conn, true
+		err := p.refreshConn(ctx, idx, pc, p.addr)
+		if err == nil {
+			return idx, p.load(idx), true
 		}
 		log.Warnf("failed to find gRPC connection pool for %s.\tlen(pool): %d,\tretried: %d,\terror: %v", p.addr, pl, cnt, err)
 		return idx, nil, false
 	}
 
 	if pl > 0 {
 		idx = int(p.current.Add(1) % pl)
-		if pc := p.load(idx); pc != nil && isHealthy(ctx, pc.conn) {
-			return idx, pc.conn, true
+		if pc = p.load(idx); pc != nil && isHealthy(ctx, pc.conn) {
+			return idx, pc, true
 		}
 	}
 	retry--
@@ -757,8 +756,8 @@
 
 func (pc *poolConn) Close(ctx context.Context, delay time.Duration) error {
 	tdelay := delay / 10
-	if tdelay < time.Millisecond*200 {
-		tdelay = time.Millisecond * 200
+	if tdelay < time.Millisecond*5 {
+		tdelay = time.Millisecond * 5
 	} else if tdelay > time.Minute {
 		tdelay = time.Second * 5
 	}

internal/net/grpc/pool/pool_test.go

@@ -2344,7 +2344,7 @@ package pool
 // 				reconnectHash: test.fields.reconnectHash,
 // 			}
 //
-// 			err := p.Disconnect()
+// 			err := p.Disconnect(context.Background)
 // 			if err := checkFunc(test.want, err); err != nil {
 // 				tt.Errorf("error = %v", err)
 // 			}

internal/test/mock/grpc/grpc_client_mock.go

@@ -51,7 +51,7 @@
 }
 
 // ConnectedAddrs calls the ConnectedAddrsFunc object.
-func (gc *GRPCClientMock) ConnectedAddrs() []string {
+func (gc *GRPCClientMock) ConnectedAddrs(_ context.Context) []string {
 	return gc.ConnectedAddrsFunc()
 }
 

internal/test/mock/grpc_testify_mock.go

@@ -199,7 +199,7 @@
 	return v
 }
 
-func (c *ClientInternal) ConnectedAddrs() []string {
+func (c *ClientInternal) ConnectedAddrs(ctx context.Context) []string {
 	args := c.Called()
 	v, ok := args.Get(0).([]string)
 	if !ok {