pkg/services: Check errors (#19712)

* pkg/services: Check errors
* pkg/services: Don't treat context.Canceled|context.DeadlineExceeded as error

pkg/services/sqlstore/migrator/migrator.go

@@ -6,6 +6,7 @@ import (
 	_ "github.com/go-sql-driver/mysql"
 	"github.com/go-xorm/xorm"
 	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/util/errutil"
 	_ "github.com/lib/pq"
 	_ "github.com/mattn/go-sqlite3"
 )
@@ -99,12 +100,14 @@ func (mg *Migrator) Start() error {
 			if err != nil {
 				mg.Logger.Error("Exec failed", "error", err, "sql", sql)
 				record.Error = err.Error()
-				sess.Insert(&record)
+				if _, err := sess.Insert(&record); err != nil {
+					return err
+				}
 				return err
 			}
 			record.Success = true
-			sess.Insert(&record)
-			return nil
+			_, err = sess.Insert(&record)
+			return err
 		})
 
 		if err != nil {
@@ -158,21 +161,22 @@ func (mg *Migrator) exec(m Migration, sess *xorm.Session) error {
 type dbTransactionFunc func(sess *xorm.Session) error
 
 func (mg *Migrator) inTransaction(callback dbTransactionFunc) error {
-	var err error
-
 	sess := mg.x.NewSession()
 	defer sess.Close()
 
-	if err = sess.Begin(); err != nil {
+	if err := sess.Begin(); err != nil {
 		return err
 	}
 
-	err = callback(sess)
+	if err := callback(sess); err != nil {
+		if rollErr := sess.Rollback(); err != rollErr {
+			return errutil.Wrapf(err, "Failed to roll back transaction due to error: %s", rollErr)
+		}
 
-	if err != nil {
-		sess.Rollback()
 		return err
-	} else if err = sess.Commit(); err != nil {
+	}
+
+	if err := sess.Commit(); err != nil {
 		return err
 	}