Remove useless Get operation

pkg/kine/server/compact.go

@@ -29,10 +29,8 @@ func (l *LimitedServer) compact(ctx context.Context) (*etcdserverpb.TxnResponse,
 				Response: &etcdserverpb.ResponseOp_ResponseRange{
 					ResponseRange: &etcdserverpb.RangeResponse{
 						Header: &etcdserverpb.ResponseHeader{},
-						Kvs: []*mvccpb.KeyValue{
-							&mvccpb.KeyValue{},
-						},
-						Count: 1,
+						Kvs:    []*mvccpb.KeyValue{{}},
+						Count:  1,
 					},
 				},
 			},

pkg/kine/server/delete.go

@@ -21,8 +21,7 @@ func isDelete(txn *etcdserverpb.TxnRequest) (int64, string, bool) {
 	return 0, "", false
 }
 
-func (l *LimitedServer) delete(ctx context.Context, key string, revision int64) (*etcdserverpb.TxnResponse, error) {
-	var err error
+func (l *LimitedServer) delete(ctx context.Context, key string, revision int64) (_ *etcdserverpb.TxnResponse, err error) {
 	deleteCnt.Add(ctx, 1)
 	ctx, span := otelTracer.Start(ctx, fmt.Sprintf("%s.delete", otelName))
 	defer func() {
@@ -57,7 +56,7 @@ func (l *LimitedServer) delete(ctx context.Context, key string, revision int64)
 			},
 		}
 	} else {
-		rev, kv, err := l.backend.Get(ctx, key, "", 1, rev)
+		rev, kv, err := l.backend.List(ctx, key, "", 1, rev)
 		if err != nil {
 			return nil, err
 		}
@@ -66,7 +65,7 @@ func (l *LimitedServer) delete(ctx context.Context, key string, revision int64)
 				Response: &etcdserverpb.ResponseOp_ResponseRange{
 					ResponseRange: &etcdserverpb.RangeResponse{
 						Header: txnHeader(rev),
-						Kvs:    toKVs(kv),
+						Kvs:    toKVs(kv...),
 					},
 				},
 			},

pkg/kine/server/get.go

@@ -19,25 +19,23 @@ func (l *LimitedServer) get(ctx context.Context, r *etcdserverpb.RangeRequest) (
 
 	span.SetAttributes(
 		attribute.String("key", string(r.Key)),
-		attribute.String("rangeEnd", string(r.RangeEnd)),
 		attribute.Int64("limit", r.Limit),
 		attribute.Int64("revision", r.Revision),
 	)
-	if r.Limit != 0 && len(r.RangeEnd) != 0 {
-		err := fmt.Errorf("invalid combination of rangeEnd and limit, limit should be 0 got %d", r.Limit)
-		return nil, err
+
+	if len(r.RangeEnd) != 0 {
+		return nil, fmt.Errorf("unexpected rangeEnd: want empty, got %s", r.RangeEnd)
+	}
+	if r.Limit != 0 {
+		return nil, fmt.Errorf("unexpected limit: want 0, got %d", r.Limit)
 	}
 
-	rev, kv, err := l.backend.Get(ctx, string(r.Key), string(r.RangeEnd), r.Limit, r.Revision)
+	rev, kv, err := l.backend.List(ctx, string(r.Key), "", 1, r.Revision)
 	if err != nil {
 		return nil, err
 	}
-
-	resp := &RangeResponse{
+	return &RangeResponse{
 		Header: txnHeader(rev),
-	}
-	if kv != nil {
-		resp.Kvs = []*KeyValue{kv}
-	}
-	return resp, nil
+		Kvs:    kv,
+	}, nil
 }

pkg/kine/server/types.go

@@ -14,7 +14,6 @@ var (
 type Backend interface {
 	Start(ctx context.Context) error
 	Wait()
-	Get(ctx context.Context, key, rangeEnd string, limit, revision int64) (int64, *KeyValue, error)
 	Create(ctx context.Context, key string, value []byte, lease int64) (int64, bool, error)
 	Delete(ctx context.Context, key string, revision int64) (int64, bool, error)
 	List(ctx context.Context, prefix, startKey string, limit, revision int64) (int64, []*KeyValue, error)

pkg/kine/server/update.go

@@ -25,12 +25,7 @@ func isUpdate(txn *etcdserverpb.TxnRequest) (int64, string, []byte, int64, bool)
 	return 0, "", nil, 0, false
 }
 
-func (l *LimitedServer) update(ctx context.Context, rev int64, key string, value []byte, lease int64) (*etcdserverpb.TxnResponse, error) {
-	var (
-		kv        *KeyValue
-		succeeded bool
-		err       error
-	)
+func (l *LimitedServer) update(ctx context.Context, rev int64, key string, value []byte, lease int64) (_ *etcdserverpb.TxnResponse, err error) {
 	updateCnt.Add(ctx, 1)
 
 	ctx, span := otelTracer.Start(ctx, fmt.Sprintf("%s.update", otelName))
@@ -44,6 +39,7 @@ func (l *LimitedServer) update(ctx context.Context, rev int64, key string, value
 		attribute.Int64("revision", rev),
 	)
 
+	var succeeded bool
 	if rev == 0 {
 		rev, succeeded, err = l.backend.Create(ctx, key, value, lease)
 	} else {
@@ -70,20 +66,18 @@ func (l *LimitedServer) update(ctx context.Context, rev int64, key string, value
 			},
 		}
 	} else {
-		rev, kv, err = l.backend.Get(ctx, key, "", 1, rev)
+		rev, kv, err := l.backend.List(ctx, key, "", 1, rev)
 		if err != nil {
 			return nil, err
 		}
-		resp.Responses = []*etcdserverpb.ResponseOp{
-			{
-				Response: &etcdserverpb.ResponseOp_ResponseRange{
-					ResponseRange: &etcdserverpb.RangeResponse{
-						Header: txnHeader(rev),
-						Kvs:    toKVs(kv),
-					},
+		resp.Responses = []*etcdserverpb.ResponseOp{{
+			Response: &etcdserverpb.ResponseOp_ResponseRange{
+				ResponseRange: &etcdserverpb.RangeResponse{
+					Header: txnHeader(rev),
+					Kvs:    toKVs(kv...),
 				},
 			},
-		}
+		}}
 	}
 
 	return resp, nil

pkg/kine/sqllog/sqllog.go

@@ -227,28 +227,6 @@ func (s *SQLLog) After(ctx context.Context, prefix string, revision, limit int64
 	return currentRevision, result, err
 }
 
-func (s *SQLLog) Get(ctx context.Context, key, rangeEnd string, limit, revision int64) (revRet int64, kvRet *server.KeyValue, errRet error) {
-	ctx, span := otelTracer.Start(ctx, fmt.Sprintf("%s.Get", otelName))
-	span.SetAttributes(
-		attribute.String("key", key),
-		attribute.String("rangeEnd", rangeEnd),
-		attribute.Int64("limit", limit),
-		attribute.Int64("revision", revision),
-	)
-	defer func() {
-		logrus.Debugf("GET %s, rev=%d => rev=%d, kv=%v, err=%v", key, revision, revRet, kvRet != nil, errRet)
-		span.SetAttributes(attribute.Int64("current-revision", revRet))
-		span.RecordError(errRet)
-		span.End()
-	}()
-
-	rev, kv, err := s.List(ctx, key, rangeEnd, limit, revision)
-	if len(kv) == 0 {
-		return rev, nil, err
-	}
-	return rev, kv[0], err
-}
-
 func (s *SQLLog) List(ctx context.Context, prefix, startKey string, limit, revision int64) (int64, []*server.KeyValue, error) {
 	var err error