Merge pull request #247 from ydb-platform/cast

ydb.GRPCConn(ydb.Connection)

Author: asmyasnikov

CHANGELOG.md

@@ -1,3 +1,4 @@
+* Added `ydb.GRPCConn(ydb.Connection)` helper for connect to driver-unsupported YDB services
 * Marked as deprecated `session.Prepare` callback
 * Marked as deprecated `options.WithQueryCachePolicyKeepInCache` and `options.WithQueryCachePolicy` options
 * Added `options.WithKeepInCache` option

connection.go

@@ -115,8 +115,6 @@ type connection struct {
 	panicCallback func(e interface{})
 }
 
-var _ grpc.ClientConnInterface = (*connection)(nil)
-
 func (c *connection) Close(ctx context.Context) error {
 	c.mtx.Lock()
 	defer c.mtx.Unlock()
@@ -429,3 +427,14 @@ func open(ctx context.Context, opts ...Option) (_ Connection, err error) {
 
 	return c, nil
 }
+
+// GRPCConn casts ydb.Connection to grpc.ClientConnInterface for executing
+// unary and streaming RPC over internal driver balancer.
+//
+// Warning: for connect to driver-unsupported YDB services
+func GRPCConn(conn Connection) grpc.ClientConnInterface {
+	if cc, ok := conn.(*connection); ok {
+		return cc
+	}
+	return nil
+}

connection_e2e_test.go

@@ -123,7 +123,7 @@ func TestConnection(t *testing.T) {
 	}()
 	t.Run("discovery.WhoAmI", func(t *testing.T) {
 		if err = retry.Retry(ctx, func(ctx context.Context) (err error) {
-			discoveryClient := Ydb_Discovery_V1.NewDiscoveryServiceClient(db.(grpc.ClientConnInterface))
+			discoveryClient := Ydb_Discovery_V1.NewDiscoveryServiceClient(ydb.GRPCConn(db))
 			response, err := discoveryClient.WhoAmI(
 				ctx,
 				&Ydb_Discovery.WhoAmIRequest{IncludeGroups: true},
@@ -143,7 +143,7 @@ func TestConnection(t *testing.T) {
 	})
 	t.Run("scripting.ExecuteYql", func(t *testing.T) {
 		if err = retry.Retry(ctx, func(ctx context.Context) (err error) {
-			scriptingClient := Ydb_Scripting_V1.NewScriptingServiceClient(db.(grpc.ClientConnInterface))
+			scriptingClient := Ydb_Scripting_V1.NewScriptingServiceClient(ydb.GRPCConn(db))
 			response, err := scriptingClient.ExecuteYql(
 				ctx,
 				&Ydb_Scripting.ExecuteYqlRequest{Script: "SELECT 1+100 AS sum"},
@@ -194,7 +194,7 @@ func TestConnection(t *testing.T) {
 	})
 	t.Run("scripting.StreamExecuteYql", func(t *testing.T) {
 		if err = retry.Retry(ctx, func(ctx context.Context) (err error) {
-			scriptingClient := Ydb_Scripting_V1.NewScriptingServiceClient(db.(grpc.ClientConnInterface))
+			scriptingClient := Ydb_Scripting_V1.NewScriptingServiceClient(ydb.GRPCConn(db))
 			client, err := scriptingClient.StreamExecuteYql(
 				ctx,
 				&Ydb_Scripting.ExecuteYqlRequest{Script: "SELECT 1+100 AS sum"},
@@ -248,7 +248,7 @@ func TestConnection(t *testing.T) {
 			_ = childDB.Close(ctx)
 		}()
 		if err = retry.Retry(ctx, func(ctx context.Context) (err error) {
-			scriptingClient := Ydb_Scripting_V1.NewScriptingServiceClient(childDB.(grpc.ClientConnInterface))
+			scriptingClient := Ydb_Scripting_V1.NewScriptingServiceClient(ydb.GRPCConn(childDB))
 			client, err := scriptingClient.StreamExecuteYql(
 				ctx,
 				&Ydb_Scripting.ExecuteYqlRequest{Script: "SELECT 1+100 AS sum"},
@@ -291,7 +291,7 @@ func TestConnection(t *testing.T) {
 	})
 	t.Run("export.ExportToS3", func(t *testing.T) {
 		if err = retry.Retry(ctx, func(ctx context.Context) (err error) {
-			exportClient := Ydb_Export_V1.NewExportServiceClient(db.(grpc.ClientConnInterface))
+			exportClient := Ydb_Export_V1.NewExportServiceClient(ydb.GRPCConn(db))
 			response, err := exportClient.ExportToS3(
 				ctx,
 				&Ydb_Export.ExportToS3Request{