YQ Connector: fix potential SQL injection in DescribeTable

1. Отрефакторен код создания PG conn string (патч от @axlodin).
2. Используем prepared statements при запросе метаданных таблицы. Для этого пришлось слегка поменять внутренние интерфейсы и добавить дженериков.

17 files changed, 211 insertions, 126 deletions

diff --git a/ydb/library/yql/providers/generic/connector/app/server/clickhouse/connection_manager.go b/ydb/library/yql/providers/generic/connector/app/server/clickhouse/connection_manager.go
index df47895d501..5cdbf69db7b 100644
--- a/ydb/library/yql/providers/generic/connector/app/server/clickhouse/connection_manager.go
+++ b/ydb/library/yql/providers/generic/connector/app/server/clickhouse/connection_manager.go
@@ -11,21 +11,20 @@ import (
 	"github.com/ClickHouse/clickhouse-go/v2"
 	"github.com/ydb-platform/ydb/library/go/core/log"
 	api_common "github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/api/common"
-	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/rdbms"
 	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/utils"
 )
 
-var _ rdbms.Connection = (*connection)(nil)
+var _ utils.Connection = (*Connection)(nil)
 
-type connection struct {
+type Connection struct {
 	*sql.DB
 }
 
-func (c connection) Query(ctx context.Context, query string, args ...any) (rdbms.Rows, error) {
+func (c Connection) Query(ctx context.Context, query string, args ...any) (utils.Rows, error) {
 	return c.DB.QueryContext(ctx, query, args...)
 }
 
-var _ rdbms.ConnectionManager = (*connectionManager)(nil)
+var _ utils.ConnectionManager[*Connection] = (*connectionManager)(nil)
 
 type connectionManager struct {
 	// TODO: cache of connections, remove unused connections with TTL
@@ -35,7 +34,7 @@ func (c *connectionManager) Make(
 	ctx context.Context,
 	logger log.Logger,
 	dsi *api_common.TDataSourceInstance,
-) (rdbms.Connection, error) {
+) (*Connection, error) {
 	if dsi.GetCredentials().GetBasic() == nil {
 		return nil, fmt.Errorf("currently only basic auth is supported")
 	}
@@ -93,13 +92,13 @@ func (c *connectionManager) Make(
 	conn.SetMaxOpenConns(maxOpenConns)
 	conn.SetConnMaxLifetime(time.Hour)
 
-	return &connection{DB: conn}, nil
+	return &Connection{DB: conn}, nil
 }
 
-func (c *connectionManager) Release(logger log.Logger, conn rdbms.Connection) {
+func (c *connectionManager) Release(logger log.Logger, conn *Connection) {
 	utils.LogCloserError(logger, conn, "close clickhouse connection")
 }
 
-func NewConnectionManager() rdbms.ConnectionManager {
+func NewConnectionManager() utils.ConnectionManager[*Connection] {
 	return &connectionManager{}
 }
diff --git a/ydb/library/yql/providers/generic/connector/app/server/clickhouse/query_builder.go b/ydb/library/yql/providers/generic/connector/app/server/clickhouse/query_builder.go
deleted file mode 100644
index c55d7058360..00000000000
--- a/ydb/library/yql/providers/generic/connector/app/server/clickhouse/query_builder.go
+++ /dev/null
@@ -1,22 +0,0 @@
-package clickhouse
-
-import (
-	"fmt"
-
-	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/rdbms"
-	api_service_protos "github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/libgo/service/protos"
-)
-
-var _ rdbms.QueryBuilder = (*queryBuilder)(nil)
-
-type queryBuilder struct {
-}
-
-func (qb queryBuilder) DescribeTable(request *api_service_protos.TDescribeTableRequest) string {
-	return fmt.Sprintf(
-		"SELECT name, type FROM system.columns WHERE table = '%s' and database ='%s'",
-		request.Table,
-		request.DataSourceInstance.Database)
-}
-
-func NewQueryBuilder() rdbms.QueryBuilder { return queryBuilder{} }
diff --git a/ydb/library/yql/providers/generic/connector/app/server/clickhouse/query_executor.go b/ydb/library/yql/providers/generic/connector/app/server/clickhouse/query_executor.go
new file mode 100644
index 00000000000..f15f8176f39
--- /dev/null
+++ b/ydb/library/yql/providers/generic/connector/app/server/clickhouse/query_executor.go
@@ -0,0 +1,31 @@
+package clickhouse
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/utils"
+	api_service_protos "github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/libgo/service/protos"
+)
+
+type queryExecutor struct {
+}
+
+func (qm queryExecutor) DescribeTable(ctx context.Context, conn *Connection, request *api_service_protos.TDescribeTableRequest) (utils.Rows, error) {
+	out, err := conn.QueryContext(
+		ctx,
+		"SELECT name, type FROM system.columns WHERE table = ? and database = ?",
+		request.Table,
+		request.DataSourceInstance.Database,
+	)
+
+	if err != nil {
+		return nil, fmt.Errorf("query: %w", err)
+	}
+
+	return out, nil
+}
+
+func NewQueryExecutor() utils.QueryExecutor[*Connection] {
+	return queryExecutor{}
+}
diff --git a/ydb/library/yql/providers/generic/connector/app/server/clickhouse/type_mapper.go b/ydb/library/yql/providers/generic/connector/app/server/clickhouse/type_mapper.go
index 93988edbd7f..42fa693d65c 100644
--- a/ydb/library/yql/providers/generic/connector/app/server/clickhouse/type_mapper.go
+++ b/ydb/library/yql/providers/generic/connector/app/server/clickhouse/type_mapper.go
@@ -262,7 +262,7 @@ func (typeMapper) appendValueToBuilder(
 func NewTypeMapper() utils.TypeMapper {
 	return typeMapper{
 		isFixedString: regexp.MustCompile(`FixedString\([0-9]+\)`),
-		isDateTime64:  regexp.MustCompile(`DateTime64\(\d\)`),
+		isDateTime64:  regexp.MustCompile(`DateTime64\(\d{1}\)`),
 		isNullable:    regexp.MustCompile(`Nullable\((?P<Internal>\w+)\)`),
 	}
 }
diff --git a/ydb/library/yql/providers/generic/connector/app/server/clickhouse/ya.make b/ydb/library/yql/providers/generic/connector/app/server/clickhouse/ya.make
index 314fa142ddb..a04c18a0aae 100644
--- a/ydb/library/yql/providers/generic/connector/app/server/clickhouse/ya.make
+++ b/ydb/library/yql/providers/generic/connector/app/server/clickhouse/ya.make
@@ -2,7 +2,7 @@ GO_LIBRARY()
 
 SRCS(
     connection_manager.go
-    query_builder.go
+    query_executor.go
     type_mapper.go
 )
 
diff --git a/ydb/library/yql/providers/generic/connector/app/server/postgresql/connection_manager.go b/ydb/library/yql/providers/generic/connector/app/server/postgresql/connection_manager.go
index 411b4af24da..2e18f4aebb6 100644
--- a/ydb/library/yql/providers/generic/connector/app/server/postgresql/connection_manager.go
+++ b/ydb/library/yql/providers/generic/connector/app/server/postgresql/connection_manager.go
@@ -5,14 +5,14 @@ import (
 	"fmt"
 
 	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
 	_ "github.com/jackc/pgx/v5/stdlib"
 	"github.com/ydb-platform/ydb/library/go/core/log"
 	api_common "github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/api/common"
-	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/rdbms"
 	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/utils"
 )
 
-var _ rdbms.Connection = (*connection)(nil)
+var _ utils.Connection = (*Connection)(nil)
 
 type rows struct {
 	pgx.Rows
@@ -23,20 +23,20 @@ func (r rows) Close() error {
 	return nil
 }
 
-type connection struct {
+type Connection struct {
 	*pgx.Conn
 }
 
-func (c connection) Close() error {
+func (c Connection) Close() error {
 	return c.Conn.Close(context.TODO())
 }
 
-func (c connection) Query(ctx context.Context, query string, args ...any) (rdbms.Rows, error) {
+func (c Connection) Query(ctx context.Context, query string, args ...any) (utils.Rows, error) {
 	out, err := c.Conn.Query(ctx, query, args...)
 	return rows{Rows: out}, err
 }
 
-var _ rdbms.ConnectionManager = (*connectionManager)(nil)
+var _ utils.ConnectionManager[*Connection] = (*connectionManager)(nil)
 
 type connectionManager struct {
 	// TODO: cache of connections, remove unused connections with TTL
@@ -46,41 +46,48 @@ func (c *connectionManager) Make(
 	ctx context.Context,
 	_ log.Logger,
 	dsi *api_common.TDataSourceInstance,
-) (rdbms.Connection, error) {
+) (*Connection, error) {
 	if dsi.GetCredentials().GetBasic() == nil {
 		return nil, fmt.Errorf("currently only basic auth is supported")
 	}
 
 	if dsi.Protocol != api_common.EProtocol_NATIVE {
-		return nil, fmt.Errorf("can not run PostgreSQL connection with protocol '%v'", dsi.Protocol)
+		return nil, fmt.Errorf("can not create PostgreSQL connection with protocol '%v'", dsi.Protocol)
 	}
 
-	connStr := fmt.Sprintf("dbname=%s user=%s password=%s host=%s port=%d",
-		dsi.Database,
-		dsi.Credentials.GetBasic().Username,
-		dsi.Credentials.GetBasic().Password,
-		dsi.GetEndpoint().GetHost(),
-		dsi.GetEndpoint().GetPort(),
-	)
+	if socketType, _ := pgconn.NetworkAddress(dsi.GetEndpoint().GetHost(), uint16(dsi.GetEndpoint().GetPort())); socketType != "tcp" {
+		return nil, fmt.Errorf("can not create PostgreSQL connection with socket type '%s'", socketType)
+	}
 
+	connStr := "dbname=DBNAME user=USER password=PASSWORD host=HOST port=5432"
 	if dsi.UseTls {
 		connStr += " sslmode=verify-full"
 	} else {
 		connStr += " sslmode=disable"
 	}
 
-	conn, err := pgx.Connect(ctx, connStr)
+	connCfg, err := pgx.ParseConfig(connStr)
+	if err != nil {
+		return nil, fmt.Errorf("parse connection config template: %w", err)
+	}
+	connCfg.Database = dsi.Database
+	connCfg.Host = dsi.GetEndpoint().GetHost()
+	connCfg.Port = uint16(dsi.GetEndpoint().GetPort())
+	connCfg.User = dsi.Credentials.GetBasic().GetUsername()
+	connCfg.Password = dsi.Credentials.GetBasic().GetPassword()
+
+	conn, err := pgx.ConnectConfig(ctx, connCfg)
 	if err != nil {
 		return nil, fmt.Errorf("open connection: %w", err)
 	}
 
-	return &connection{Conn: conn}, nil
+	return &Connection{conn}, nil
 }
 
-func (c *connectionManager) Release(logger log.Logger, conn rdbms.Connection) {
-	utils.LogCloserError(logger, conn, "close connection to PostgreSQL")
+func (c *connectionManager) Release(logger log.Logger, conn *Connection) {
+	utils.LogCloserError(logger, conn, "close posgresql connection")
 }
 
-func NewConnectionManager() rdbms.ConnectionManager {
+func NewConnectionManager() utils.ConnectionManager[*Connection] {
 	return &connectionManager{}
 }
diff --git a/ydb/library/yql/providers/generic/connector/app/server/postgresql/query_builder.go b/ydb/library/yql/providers/generic/connector/app/server/postgresql/query_builder.go
deleted file mode 100644
index c7dbdfdcdab..00000000000
--- a/ydb/library/yql/providers/generic/connector/app/server/postgresql/query_builder.go
+++ /dev/null
@@ -1,22 +0,0 @@
-package postgresql
-
-import (
-	"fmt"
-
-	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/rdbms"
-	api_service_protos "github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/libgo/service/protos"
-)
-
-var _ rdbms.QueryBuilder = (*queryBuilder)(nil)
-
-type queryBuilder struct {
-}
-
-func (qb queryBuilder) DescribeTable(request *api_service_protos.TDescribeTableRequest) string {
-	return fmt.Sprintf(
-		// TODO: is hardconing schema correct?
-		"SELECT column_name, data_type FROM information_schema.columns WHERE table_name = '%s' AND table_schema ='public'",
-		request.Table)
-}
-
-func NewQueryBuilder() rdbms.QueryBuilder { return queryBuilder{} }
diff --git a/ydb/library/yql/providers/generic/connector/app/server/postgresql/query_executor.go b/ydb/library/yql/providers/generic/connector/app/server/postgresql/query_executor.go
new file mode 100644
index 00000000000..c61292f25dd
--- /dev/null
+++ b/ydb/library/yql/providers/generic/connector/app/server/postgresql/query_executor.go
@@ -0,0 +1,30 @@
+package postgresql
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/utils"
+	api_service_protos "github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/libgo/service/protos"
+)
+
+type queryExecutor struct {
+}
+
+func (qm queryExecutor) DescribeTable(ctx context.Context, conn *Connection, request *api_service_protos.TDescribeTableRequest) (utils.Rows, error) {
+	out, err := conn.Query(
+		ctx,
+		"SELECT column_name, data_type FROM information_schema.columns WHERE table_name = $1 AND table_schema ='public'",
+		request.Table,
+	)
+
+	if err != nil {
+		return nil, fmt.Errorf("connection query: %w", err)
+	}
+
+	return out, nil
+}
+
+func NewQueryExecutor() utils.QueryExecutor[*Connection] {
+	return queryExecutor{}
+}
diff --git a/ydb/library/yql/providers/generic/connector/app/server/postgresql/ya.make b/ydb/library/yql/providers/generic/connector/app/server/postgresql/ya.make
index 314fa142ddb..a04c18a0aae 100644
--- a/ydb/library/yql/providers/generic/connector/app/server/postgresql/ya.make
+++ b/ydb/library/yql/providers/generic/connector/app/server/postgresql/ya.make
@@ -2,7 +2,7 @@ GO_LIBRARY()
 
 SRCS(
     connection_manager.go
-    query_builder.go
+    query_executor.go
     type_mapper.go
 )
 
diff --git a/ydb/library/yql/providers/generic/connector/app/server/rdbms/handler.go b/ydb/library/yql/providers/generic/connector/app/server/rdbms/handler.go
index 1792cfbe855..4e571031051 100644
--- a/ydb/library/yql/providers/generic/connector/app/server/rdbms/handler.go
+++ b/ydb/library/yql/providers/generic/connector/app/server/rdbms/handler.go
@@ -11,20 +11,36 @@ import (
 	api_service_protos "github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/libgo/service/protos"
 )
 
-type Handler struct {
+type Handler interface {
+	DescribeTable(
+		ctx context.Context,
+		logger log.Logger,
+		request *api_service_protos.TDescribeTableRequest,
+	) (*api_service_protos.TDescribeTableResponse, error)
+
+	ReadSplit(
+		ctx context.Context,
+		logger log.Logger,
+		dataSourceInstance *api_common.TDataSourceInstance,
+		split *api_service_protos.TSplit,
+		pagingWriter *utils.PagingWriter,
+	) error
+
+	TypeMapper() utils.TypeMapper
+}
+
+type handlerImpl[CONN utils.Connection] struct {
 	typeMapper        utils.TypeMapper
-	queryBuilder      QueryBuilder
-	connectionManager ConnectionManager
+	queryBuilder      utils.QueryExecutor[CONN]
+	connectionManager utils.ConnectionManager[CONN]
 	logger            log.Logger
 }
 
-func (h *Handler) DescribeTable(
+func (h *handlerImpl[CONN]) DescribeTable(
 	ctx context.Context,
 	logger log.Logger,
 	request *api_service_protos.TDescribeTableRequest,
 ) (*api_service_protos.TDescribeTableResponse, error) {
-	query := h.queryBuilder.DescribeTable(request)
-
 	conn, err := h.connectionManager.Make(ctx, logger, request.DataSourceInstance)
 	if err != nil {
 		return nil, fmt.Errorf("make connection: %w", err)
@@ -32,13 +48,12 @@ func (h *Handler) DescribeTable(
 
 	defer h.connectionManager.Release(logger, conn)
 
-	logger.Debug("execute query", log.String("query", query))
-
-	rows, err := conn.Query(ctx, query)
+	rows, err := h.queryBuilder.DescribeTable(ctx, conn, request)
 	if err != nil {
-		return nil, fmt.Errorf("query '%s' error: %w", query, err)
+		return nil, fmt.Errorf("query builder error: %w", err)
 	}
 
+	// logger.Debug("execute query", log.String("query", query))
 	defer func() { utils.LogCloserError(logger, rows, "close rows") }()
 
 	var (
@@ -71,7 +86,7 @@ func (h *Handler) DescribeTable(
 	return &api_service_protos.TDescribeTableResponse{Schema: &schema}, nil
 }
 
-func (h *Handler) ReadSplit(
+func (h *handlerImpl[CONN]) ReadSplit(
 	ctx context.Context,
 	logger log.Logger,
 	dataSourceInstance *api_common.TDataSourceInstance,
@@ -156,8 +171,16 @@ func (h *Handler) ReadSplit(
 	return nil
 }
 
-func (h *Handler) TypeMapper() utils.TypeMapper { return h.typeMapper }
+func (h *handlerImpl[CONN]) TypeMapper() utils.TypeMapper { return h.typeMapper }
 
-func NewHandler(logger log.Logger, queryBuilder QueryBuilder, connectionManager ConnectionManager, typeMapper utils.TypeMapper) *Handler {
-	return &Handler{logger: logger, queryBuilder: queryBuilder, connectionManager: connectionManager, typeMapper: typeMapper}
+func newHandler[CONN utils.Connection](
+	logger log.Logger,
+	preset *preset[CONN],
+) Handler {
+	return &handlerImpl[CONN]{
+		logger:            logger,
+		queryBuilder:      preset.queryExecutor,
+		connectionManager: preset.connectionManager,
+		typeMapper:        preset.typeMapper,
+	}
 }
diff --git a/ydb/library/yql/providers/generic/connector/app/server/rdbms/handler_factory.go b/ydb/library/yql/providers/generic/connector/app/server/rdbms/handler_factory.go
new file mode 100644
index 00000000000..e7d03426b15
--- /dev/null
+++ b/ydb/library/yql/providers/generic/connector/app/server/rdbms/handler_factory.go
@@ -0,0 +1,52 @@
+package rdbms
+
+import (
+	"fmt"
+
+	"github.com/ydb-platform/ydb/library/go/core/log"
+	api_common "github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/api/common"
+	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/clickhouse"
+	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/postgresql"
+	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/utils"
+)
+
+type preset[CONN utils.Connection] struct {
+	queryExecutor     utils.QueryExecutor[CONN]
+	connectionManager utils.ConnectionManager[CONN]
+	typeMapper        utils.TypeMapper
+}
+
+type HandlerFactory struct {
+	clickhouse preset[*clickhouse.Connection]
+	postgresql preset[*postgresql.Connection]
+}
+
+func (hf *HandlerFactory) Make(
+	logger log.Logger,
+	dataSourceType api_common.EDataSourceKind,
+) (Handler, error) {
+
+	switch dataSourceType {
+	case api_common.EDataSourceKind_CLICKHOUSE:
+		return newHandler[*clickhouse.Connection](logger, &hf.clickhouse), nil
+	case api_common.EDataSourceKind_POSTGRESQL:
+		return newHandler[*postgresql.Connection](logger, &hf.postgresql), nil
+	default:
+		return nil, fmt.Errorf("pick handler for data source type '%v': %w", dataSourceType, utils.ErrDataSourceNotSupported)
+	}
+}
+
+func NewHandlerFactory() *HandlerFactory {
+	return &HandlerFactory{
+		clickhouse: preset[*clickhouse.Connection]{
+			queryExecutor:     clickhouse.NewQueryExecutor(),
+			connectionManager: clickhouse.NewConnectionManager(),
+			typeMapper:        clickhouse.NewTypeMapper(),
+		},
+		postgresql: preset[*postgresql.Connection]{
+			queryExecutor:     postgresql.NewQueryExecutor(),
+			connectionManager: postgresql.NewConnectionManager(),
+			typeMapper:        postgresql.NewTypeMapper(),
+		},
+	}
+}
diff --git a/ydb/library/yql/providers/generic/connector/app/server/rdbms/query_builder.go b/ydb/library/yql/providers/generic/connector/app/server/rdbms/query_builder.go
deleted file mode 100644
index 6aa6e7991b9..00000000000
--- a/ydb/library/yql/providers/generic/connector/app/server/rdbms/query_builder.go
+++ /dev/null
@@ -1,9 +0,0 @@
-package rdbms
-
-import (
-	api_service_protos "github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/libgo/service/protos"
-)
-
-type QueryBuilder interface {
-	DescribeTable(request *api_service_protos.TDescribeTableRequest) string
-}
diff --git a/ydb/library/yql/providers/generic/connector/app/server/rdbms/ya.make b/ydb/library/yql/providers/generic/connector/app/server/rdbms/ya.make
index f73218d66d5..b89c13e8570 100644
--- a/ydb/library/yql/providers/generic/connector/app/server/rdbms/ya.make
+++ b/ydb/library/yql/providers/generic/connector/app/server/rdbms/ya.make
@@ -1,9 +1,8 @@
 GO_LIBRARY()
 
 SRCS(
-    connection_manager.go
     handler.go
-    query_builder.go
+    handler_factory.go
 )
 
 END()
diff --git a/ydb/library/yql/providers/generic/connector/app/server/server.go b/ydb/library/yql/providers/generic/connector/app/server/server.go
index 85f88108b9b..30deb25ea07 100644
--- a/ydb/library/yql/providers/generic/connector/app/server/server.go
+++ b/ydb/library/yql/providers/generic/connector/app/server/server.go
@@ -8,10 +8,7 @@ import (
 	"github.com/apache/arrow/go/v13/arrow/memory"
 	"github.com/spf13/cobra"
 	"github.com/ydb-platform/ydb/library/go/core/log"
-	api_common "github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/api/common"
 	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/config"
-	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/clickhouse"
-	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/postgresql"
 	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/rdbms"
 	"github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/app/server/utils"
 	api_service "github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/libgo/service"
@@ -22,7 +19,7 @@ import (
 
 type Server struct {
 	api_service.UnimplementedConnectorServer
-	handlers              map[api_common.EDataSourceKind]*rdbms.Handler
+	handlerFactory        *rdbms.HandlerFactory
 	columnarBufferFactory *utils.ColumnarBufferFactory
 	cfg                   *config.ServerConfig
 	logger                log.Logger
@@ -47,7 +44,7 @@ func (s *Server) DescribeTable(
 		}, nil
 	}
 
-	handler, err := s.getHandler(request.DataSourceInstance.Kind)
+	handler, err := s.handlerFactory.Make(logger, request.DataSourceInstance.Kind)
 	if err != nil {
 		logger.Error("request handling failed", log.Error(err))
 
@@ -181,7 +178,7 @@ func (s *Server) readSplit(
 ) error {
 	logger.Debug("reading split", log.String("split", split.String()))
 
-	handler, err := s.getHandler(request.DataSourceInstance.Kind)
+	handler, err := s.handlerFactory.Make(logger, request.DataSourceInstance.Kind)
 	if err != nil {
 		return fmt.Errorf("get handler: %w", err)
 	}
@@ -261,25 +258,12 @@ func (s *Server) makeOptions() ([]grpc.ServerOption, error) {
 	return opts, nil
 }
 
-func (s *Server) getHandler(dataSourceType api_common.EDataSourceKind) (*rdbms.Handler, error) {
-	if h, ok := s.handlers[dataSourceType]; ok {
-		return h, nil
-	}
-
-	return nil, fmt.Errorf("pick handler for data source type '%v': %w", dataSourceType, utils.ErrDataSourceNotSupported)
-}
-
 func newServer(
 	logger log.Logger,
 	cfg *config.ServerConfig,
 ) (*Server, error) {
 	return &Server{
-		handlers: map[api_common.EDataSourceKind]*rdbms.Handler{
-			api_common.EDataSourceKind_CLICKHOUSE: rdbms.NewHandler(
-				logger, clickhouse.NewQueryBuilder(), clickhouse.NewConnectionManager(), clickhouse.NewTypeMapper()),
-			api_common.EDataSourceKind_POSTGRESQL: rdbms.NewHandler(
-				logger, postgresql.NewQueryBuilder(), postgresql.NewConnectionManager(), postgresql.NewTypeMapper()),
-		},
+		handlerFactory: rdbms.NewHandlerFactory(),
 		columnarBufferFactory: utils.NewColumnarBufferFactory(
 			memory.DefaultAllocator,
 			utils.NewReadLimiterFactory(cfg.ReadLimit),
diff --git a/ydb/library/yql/providers/generic/connector/app/server/rdbms/connection_manager.go b/ydb/library/yql/providers/generic/connector/app/server/utils/connection_manager.go
index 7327322f0f6..46738960b8b 100644
--- a/ydb/library/yql/providers/generic/connector/app/server/rdbms/connection_manager.go
+++ b/ydb/library/yql/providers/generic/connector/app/server/utils/connection_manager.go
@@ -1,4 +1,4 @@
-package rdbms
+package utils
 
 import (
 	"context"
@@ -19,7 +19,7 @@ type Rows interface {
 	Scan(dest ...any) error
 }
 
-type ConnectionManager interface {
-	Make(ctx context.Context, logger log.Logger, dataSourceInstance *api_common.TDataSourceInstance) (Connection, error)
-	Release(logger log.Logger, conn Connection)
+type ConnectionManager[CONN any] interface {
+	Make(ctx context.Context, logger log.Logger, dataSourceInstance *api_common.TDataSourceInstance) (CONN, error)
+	Release(logger log.Logger, conn CONN)
 }
diff --git a/ydb/library/yql/providers/generic/connector/app/server/utils/query_builder.go b/ydb/library/yql/providers/generic/connector/app/server/utils/query_builder.go
new file mode 100644
index 00000000000..5e8fe2a0be7
--- /dev/null
+++ b/ydb/library/yql/providers/generic/connector/app/server/utils/query_builder.go
@@ -0,0 +1,11 @@
+package utils
+
+import (
+	"context"
+
+	api_service_protos "github.com/ydb-platform/ydb/ydb/library/yql/providers/generic/connector/libgo/service/protos"
+)
+
+type QueryExecutor[CONN Connection] interface {
+	DescribeTable(ctx context.Context, conn CONN, request *api_service_protos.TDescribeTableRequest) (Rows, error)
+}
diff --git a/ydb/library/yql/providers/generic/connector/app/server/utils/ya.make b/ydb/library/yql/providers/generic/connector/app/server/utils/ya.make
index 1b9a99f962f..0e57385587d 100644
--- a/ydb/library/yql/providers/generic/connector/app/server/utils/ya.make
+++ b/ydb/library/yql/providers/generic/connector/app/server/utils/ya.make
@@ -4,12 +4,14 @@ SRCS(
     arrow_helpers.go
     columnar_buffer_arrow_ipc_streaming.go
     columnar_buffer_factory.go
+    connection_manager.go
     converters.go
-    errors.go
     endpoint.go
+    errors.go
     logger.go
     paging_writer.go
     protobuf.go
+    query_builder.go
     read_limiter.go
     select_helpers.go
     time.go