Chore: Add initial/experimental xorm spanner driver (#101398)

* make it build and start

* run some migrations

* add build tags, remove log

* remove unused code

* revert go.mod changes

* move initialisation into dialect file

* update workspace

* update workspace once again

* clean up dependencies

* further cleanup

* Address some review feedback.

* Fix go.sum.

---------

Co-authored-by: Peter Štibraný <pstibrany@gmail.com>

pkg/services/sqlstore/database_config.go

@@ -203,6 +203,8 @@ func (dbCfg *DatabaseConfig) buildConnectionString(cfg *setting.Cfg, features fe
 		}
 
 		cnnstr += buildExtraConnectionString('&', dbCfg.UrlQueryParams)
+	case migrator.Spanner:
+		cnnstr = dbCfg.Name
 	default:
 		return fmt.Errorf("unknown database type: %s", dbCfg.Type)
 	}

pkg/services/sqlstore/migrator/migrations.go

@@ -85,6 +85,10 @@ func (m *RawSQLMigration) Mssql(sql string) *RawSQLMigration {
 	return m.Set(MSSQL, sql)
 }
 
+func (m *RawSQLMigration) Spanner(sql string) *RawSQLMigration {
+	return m.Set(Spanner, sql)
+}
+
 type AddColumnMigration struct {
 	MigrationBase
 	tableName string

pkg/services/sqlstore/migrator/migrator.go

@@ -400,6 +400,11 @@ func (mg *Migrator) InTransaction(callback dbTransactionFunc) error {
 	sess := mg.DBEngine.NewSession()
 	defer sess.Close()
 
+	// XXX: Spanner cannot execute DDL statements in transactions
+	if mg.Dialect.DriverName() == Spanner {
+		return callback(sess)
+	}
+
 	if err := sess.Begin(); err != nil {
 		return err
 	}

pkg/services/sqlstore/migrator/spanner_dialect.go

@@ -0,0 +1,84 @@
+//go:build enterprise || pro
+
+package migrator
+
+import (
+	"errors"
+	"fmt"
+
+	"cloud.google.com/go/spanner"
+	"google.golang.org/grpc/codes"
+	"xorm.io/core"
+)
+
+type SpannerDialect struct {
+	BaseDialect
+	d core.Dialect
+}
+
+func init() {
+	supportedDialects[Spanner] = NewSpannerDialect
+}
+
+func NewSpannerDialect() Dialect {
+	d := SpannerDialect{d: core.QueryDialect(Spanner)}
+	d.BaseDialect.dialect = &d
+	d.BaseDialect.driverName = Spanner
+	return &d
+}
+
+func (s *SpannerDialect) AutoIncrStr() string      { return s.d.AutoIncrStr() }
+func (s *SpannerDialect) Quote(name string) string { return s.d.Quote(name) }
+func (s *SpannerDialect) SupportEngine() bool      { return s.d.SupportEngine() }
+func (s *SpannerDialect) IndexCheckSQL(tableName, indexName string) (string, []any) {
+	return s.d.IndexCheckSql(tableName, indexName)
+}
+func (s *SpannerDialect) SQLType(col *Column) string {
+	c := core.NewColumn(col.Name, "", core.SQLType{Name: col.Type}, col.Length, col.Length2, col.Nullable)
+	return s.d.SqlType(c)
+}
+
+func (s *SpannerDialect) BatchSize() int { return 1000 }
+func (s *SpannerDialect) BooleanStr(b bool) string {
+	if b {
+		return "true"
+	}
+	return "false"
+}
+func (s *SpannerDialect) ErrorMessage(err error) string {
+	return spanner.ErrDesc(spanner.ToSpannerError(err))
+}
+func (s *SpannerDialect) IsDeadlock(err error) bool {
+	return spanner.ErrCode(spanner.ToSpannerError(err)) == codes.Aborted
+}
+func (s *SpannerDialect) IsUniqueConstraintViolation(err error) bool {
+	return spanner.ErrCode(spanner.ToSpannerError(err)) == codes.AlreadyExists
+}
+
+func (s *SpannerDialect) CreateTableSQL(table *Table) string {
+	t := core.NewEmptyTable()
+	t.Name = table.Name
+	t.PrimaryKeys = table.PrimaryKeys
+	for _, c := range table.Columns {
+		t.AddColumn(core.NewColumn(c.Name, c.Name, core.SQLType{Name: c.Type}, c.Length, c.Length2, c.Nullable))
+	}
+	return s.d.CreateTableSql(t, t.Name, "", "")
+}
+
+func (s *SpannerDialect) CreateIndexSQL(tableName string, index *Index) string {
+	idx := core.NewIndex(index.Name, index.Type)
+	idx.Cols = index.Cols
+	return s.d.CreateIndexSql(tableName, idx)
+}
+
+func (s *SpannerDialect) UpsertMultipleSQL(tableName string, keyCols, updateCols []string, count int) (string, error) {
+	return "", errors.New("not supported")
+}
+
+func (s *SpannerDialect) DropIndexSQL(tableName string, index *Index) string {
+	return fmt.Sprintf("DROP INDEX %v", s.Quote(index.XName(tableName)))
+}
+
+func (s *SpannerDialect) DropTable(tableName string) string {
+	return fmt.Sprintf("DROP TABLE %s", s.Quote(tableName))
+}

pkg/services/sqlstore/migrator/types.go

@@ -12,6 +12,7 @@ const (
 	SQLite   = "sqlite3"
 	MySQL    = "mysql"
 	MSSQL    = "mssql"
+	Spanner  = "spanner"
 )
 
 type Migration interface {