Alerting: add safeguard for migrations that might cause dataloss (#48526)

* Alerting: add safeguard for migrations that might cause dataloss

* add test for panic

* add documentation

conf/defaults.ini

@@ -9,6 +9,9 @@ app_mode = production
 # instance name, defaults to HOSTNAME environment variable value or hostname if HOSTNAME var is empty
 instance_name = ${HOSTNAME}
 
+# force migration will run migrations that might cause dataloss
+force_migration = false
+
 #################################### Paths ###############################
 [paths]
 # Path to where grafana can store temp files, sessions, and the sqlite3 db (if that is used)

conf/sample.ini

@@ -9,6 +9,9 @@
 # instance name, defaults to HOSTNAME environment variable value or hostname if HOSTNAME var is empty
 ;instance_name = ${HOSTNAME}
 
+# force migration will run migrations that might cause dataloss
+;force_migration = false
+
 #################################### Paths ####################################
 [paths]
 # Path to where grafana can store temp files, sessions, and the sqlite3 db (if that is used)

docs/sources/administration/configuration.md

@@ -135,6 +135,10 @@ Options are `production` and `development`. Default is `production`. _Do not_ ch
 Set the name of the grafana-server instance. Used in logging, internal metrics, and clustering info. Defaults to: `${HOSTNAME}`, which will be replaced with
 environment variable `HOSTNAME`, if that is empty or does not exist Grafana will try to use system calls to get the machine name.
 
+### force_migration
+
+Force migration will run migrations that might cause data loss. Default is `false`.
+
 <hr />
 
 ## [paths]

pkg/services/sqlstore/migrations/ualert/migration_test.go

@@ -29,6 +29,7 @@ func TestAddDashAlertMigration(t *testing.T) {
 		name           string
 		config         *setting.Cfg
 		isMigrationRun bool
+		shouldPanic    bool
 		expected       []string // set of migration titles
 	}{
 		{
@@ -47,6 +48,18 @@ func TestAddDashAlertMigration(t *testing.T) {
 				UnifiedAlerting: setting.UnifiedAlertingSettings{
 					Enabled: boolPointer(false),
 				},
+				ForceMigration: true,
+			},
+			isMigrationRun: true,
+			expected:       []string{fmt.Sprintf(ualert.ClearMigrationEntryTitle, ualert.MigTitle), ualert.RmMigTitle},
+		},
+		{
+			name: "when unified alerting disabled, migration is already run and force migration is disabled, then the migration should panic",
+			config: &setting.Cfg{
+				UnifiedAlerting: setting.UnifiedAlertingSettings{
+					Enabled: boolPointer(false),
+				},
+				ForceMigration: false,
 			},
 			isMigrationRun: true,
 			expected:       []string{fmt.Sprintf(ualert.ClearMigrationEntryTitle, ualert.MigTitle), ualert.RmMigTitle},
@@ -75,6 +88,12 @@ func TestAddDashAlertMigration(t *testing.T) {
 
 	for _, tt := range tc {
 		t.Run(tt.name, func(t *testing.T) {
+			defer func() {
+				// if the code should panic, make sure it has
+				if r := recover(); r == nil && tt.shouldPanic {
+					t.Errorf("The code did not panic")
+				}
+			}()
 			if tt.isMigrationRun {
 				log := migrator.MigrationLog{
 					MigrationID: ualert.MigTitle,
@@ -90,6 +109,7 @@ func TestAddDashAlertMigration(t *testing.T) {
 			}
 
 			mg := migrator.NewMigrator(x, tt.config)
+
 			ualert.AddDashAlertMigration(mg)
 			require.Equal(t, tt.expected, mg.GetMigrationIDs(false))
 		})

pkg/services/sqlstore/migrations/ualert/ualert.go

@@ -73,6 +73,10 @@ func AddDashAlertMigration(mg *migrator.Migrator) {
 			silences:        make(map[int64][]*pb.MeshSilence),
 		})
 	case !mg.Cfg.UnifiedAlerting.IsEnabled() && migrationRun:
+		// Safeguard to prevent data loss when migrating from UA to LA
+		if !mg.Cfg.ForceMigration {
+			panic("New alert rules created while using unified alerting will be deleted, set force_migration=true in your grafana.ini and try again if this is okay.")
+		}
 		// Remove the migration entry that creates unified alerting data. This is so when the feature
 		// flag is enabled in the future the migration "move dashboard alerts to unified alerting" will be run again.
 		mg.AddMigration(fmt.Sprintf(clearMigrationEntryTitle, migTitle), &clearMigrationEntry{

pkg/setting/setting.go

@@ -386,6 +386,8 @@ type Cfg struct {
 
 	Env string
 
+	ForceMigration bool
+
 	// Analytics
 	CheckForGrafanaUpdates              bool
 	CheckForPluginUpdates               bool
@@ -886,6 +888,7 @@ func (cfg *Cfg) Load(args CommandLineArgs) error {
 
 	Env = valueAsString(iniFile.Section(""), "app_mode", "development")
 	cfg.Env = Env
+	cfg.ForceMigration = iniFile.Section("").Key("force_migration").MustBool(false)
 	InstanceName = valueAsString(iniFile.Section(""), "instance_name", "unknown_instance_name")
 	plugins := valueAsString(iniFile.Section("paths"), "plugins", "")
 	cfg.PluginsPath = makeAbsolute(plugins, HomePath)