ResourceServer: Resource store sql backend (#90170)

pkg/storage/unified/sql/db/service.go

@@ -0,0 +1,71 @@
+package db
+
+import (
+	"context"
+	"database/sql"
+
+	"xorm.io/xorm"
+
+	"github.com/grafana/grafana/pkg/services/sqlstore/session"
+	"github.com/grafana/grafana/pkg/setting"
+)
+
+const (
+	DriverPostgres = "postgres"
+	DriverMySQL    = "mysql"
+	DriverSQLite   = "sqlite"
+	DriverSQLite3  = "sqlite3"
+)
+
+// ResourceDBInterface provides access to a database capable of supporting the
+// Entity Server.
+type ResourceDBInterface interface {
+	Init() error
+	GetCfg() *setting.Cfg
+	GetDB() (DB, error)
+
+	// TODO: deprecate.
+	GetSession() (*session.SessionDB, error)
+	GetEngine() (*xorm.Engine, error)
+}
+
+// DB is a thin abstraction on *sql.DB to allow mocking to provide better unit
+// testing. We purposefully hide database operation methods that would use
+// context.Background().
+type DB interface {
+	ContextExecer
+	BeginTx(context.Context, *sql.TxOptions) (Tx, error)
+	WithTx(context.Context, *sql.TxOptions, TxFunc) error
+	PingContext(context.Context) error
+	Stats() sql.DBStats
+	DriverName() string
+}
+
+// TxFunc is a function that executes with access to a transaction. The context
+// it receives is the same context used to create the transaction, and is
+// provided so that a general prupose TxFunc is able to retrieve information
+// from that context, and derive other contexts that may be used to run database
+// operation methods accepting a context. A derived context can be used to
+// request a specific database operation to take no more than a specific
+// fraction of the remaining timeout of the transaction context, or to enrich
+// the downstream observability layer with relevant information regarding the
+// specific operation being carried out.
+type TxFunc = func(context.Context, Tx) error
+
+// Tx is a thin abstraction on *sql.Tx to allow mocking to provide better unit
+// testing. We allow database operation methods that do not take a
+// context.Context here since a Tx can only be obtained with DB.BeginTx, which
+// already takes a context.Context.
+type Tx interface {
+	ContextExecer
+	Commit() error
+	Rollback() error
+}
+
+// ContextExecer is a set of database operation methods that take
+// context.Context.
+type ContextExecer interface {
+	ExecContext(ctx context.Context, query string, args ...any) (sql.Result, error)
+	QueryContext(ctx context.Context, query string, args ...any) (*sql.Rows, error)
+	QueryRowContext(ctx context.Context, query string, args ...any) *sql.Row
+}