Alerting: Alert Rule migration (#33000)

* Not complete, put migration behind env flag for now:
UALERT_MIG=iDidBackup
* Important to backup, and not expect the same DB to keep working until the env trigger is removed.
* Alerting: Migrate dashboard alert permissions
* Do not use imported models
* Change folder titles

Co-authored-by: Sofia Papagiannaki <papagian@users.noreply.github.com>

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

@@ -0,0 +1,123 @@
+package ualert
+
+import (
+	"encoding/json"
+	"time"
+)
+
+type dashAlert struct {
+	Id          int64
+	OrgId       int64
+	DashboardId int64
+	PanelId     int64
+	Name        string
+	Message     string
+	Frequency   int64
+	For         time.Duration
+
+	Settings       json.RawMessage
+	ParsedSettings *dashAlertSettings
+	DashboardUID   string // Set from separate call
+}
+
+var slurpDashSQL = `
+SELECT id, 
+	org_id, 
+	dashboard_id,
+	panel_id,
+	org_id,
+	name,
+	message,
+	frequency,
+	for,
+	settings
+FROM
+	alert
+`
+
+// slurpDashAlerts loads all alerts from the alert database table into the
+// the dashAlert type.
+// Additionally it unmarshals the json settings for the alert into the
+// ParsedSettings property of the dash alert.
+func (m *migration) slurpDashAlerts() ([]dashAlert, error) {
+	dashAlerts := []dashAlert{}
+	err := m.sess.SQL(slurpDashSQL).Find(&dashAlerts)
+
+	if err != nil {
+		return nil, err
+	}
+
+	for i := range dashAlerts {
+		err = json.Unmarshal(dashAlerts[i].Settings, &dashAlerts[i].ParsedSettings)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return dashAlerts, nil
+}
+
+// dashAlertSettings is a type for the JSON that is in the settings field of
+// the alert table.
+type dashAlertSettings struct {
+	NoDataState         string               `json:"noDataState"`
+	ExecutionErrorState string               `json:"executionErrorState"`
+	Conditions          []dashAlertCondition `json:"conditions"`
+	AlertRuleTags       map[string]string    `json:"alertRuleTags"`
+	Notifications       []dashAlertNot       `json:"notifications"`
+}
+
+// dashAlertNot is the object that represents the Notifications array in
+// dashAlertSettings
+type dashAlertNot struct {
+	UID string `json:"uid"`
+}
+
+// dashAlertingConditionJSON is like classic.ClassicConditionJSON except that it
+// includes the model property with the query.
+type dashAlertCondition struct {
+	Evaluator conditionEvalJSON `json:"evaluator"`
+
+	Operator struct {
+		Type string `json:"type"`
+	} `json:"operator"`
+
+	Query struct {
+		Params       []string `json:"params"`
+		DatasourceID int64    `json:"datasourceId"`
+		Model        json.RawMessage
+	} `json:"query"`
+
+	Reducer struct {
+		// Params []interface{} `json:"params"` (Unused)
+		Type string `json:"type"`
+	}
+}
+
+type conditionEvalJSON struct {
+	Params []float64 `json:"params"`
+	Type   string    `json:"type"` // e.g. "gt"
+}
+
+// slurpDashUIDs returns a map of [orgID, dashboardId] -> dashUID.
+func (m *migration) slurpDashUIDs() (map[[2]int64]string, error) {
+	dashIDs := []struct {
+		OrgID int64  `xorm:"org_id"`
+		ID    int64  `xorm:"id"`
+		UID   string `xorm:"uid"`
+	}{}
+
+	err := m.sess.SQL(`SELECT org_id, id, uid FROM dashboard`).Find(&dashIDs)
+
+	if err != nil {
+		return nil, err
+	}
+
+	idToUID := make(map[[2]int64]string, len(dashIDs))
+
+	for _, ds := range dashIDs {
+		idToUID[[2]int64{ds.OrgID, ds.ID}] = ds.UID
+	}
+
+	return idToUID, nil
+}