Alerting: Remove url based external alertmanagers config (#57918)

* Remove URL-based alertmanagers from endpoint config

* WIP

* Add migration and alertmanagers from admin_configuration

* Empty comment removed

* set BasicAuth true when user is present in url

* Remove Alertmanagers from GET /admin_config payload

* Remove URL-based alertmanager configuration from UI

* Fix new uid generation in external alertmanagers migration

* Fix tests for URL-based external alertmanagers

* Fix API tests

* Add more tests, move migration code to separate file, and remove possible am duplicate urls

* Fix edge cases in migration

* Fix imports

* Remove useless fields and fix created_at/updated_at retrieval

Co-authored-by: George Robinson <george.robinson@grafana.com>
Co-authored-by: Konrad Lalik <konrad.lalik@grafana.com>

pkg/services/sqlstore/migrations/external_alertmanagers.go

@@ -0,0 +1,125 @@
+package migrations
+
+import (
+	"fmt"
+	"net/url"
+	"time"
+
+	"github.com/grafana/grafana/pkg/components/simplejson"
+	"github.com/grafana/grafana/pkg/services/datasources"
+	"github.com/grafana/grafana/pkg/services/sqlstore/migrations/ualert"
+	"github.com/grafana/grafana/pkg/services/sqlstore/migrator"
+	"github.com/grafana/grafana/pkg/util"
+	"xorm.io/xorm"
+)
+
+func AddExternalAlertmanagerToDatasourceMigration(mg *migrator.Migrator) {
+	mg.AddMigration("migrate external alertmanagers to datsourcse", &externalAlertmanagerToDatasources{})
+}
+
+type externalAlertmanagerToDatasources struct {
+	migrator.MigrationBase
+}
+
+type AdminConfiguration struct {
+	OrgID int64 `xorm:"org_id"`
+
+	Alertmanagers []string
+
+	CreatedAt int64 `xorm:"created_at"`
+	UpdatedAt int64 `xorm:"updated_at"`
+}
+
+func (e externalAlertmanagerToDatasources) SQL(dialect migrator.Dialect) string {
+	return "migrate external alertmanagers to datasource"
+}
+
+func (e externalAlertmanagerToDatasources) Exec(sess *xorm.Session, mg *migrator.Migrator) error {
+	var results []AdminConfiguration
+	err := sess.SQL("SELECT org_id, alertmanagers, created_at, updated_at FROM ngalert_configuration").Find(&results)
+	if err != nil {
+		return err
+	}
+
+	for _, result := range results {
+		for _, am := range removeDuplicates(result.Alertmanagers) {
+			u, err := url.Parse(am)
+			if err != nil {
+				return err
+			}
+			uri := fmt.Sprintf("%s://%s%s", u.Scheme, u.Host, u.Path)
+
+			uid, err := generateNewDatasourceUid(sess, result.OrgID)
+			if err != nil {
+				return err
+			}
+			ds := &datasources.DataSource{
+				OrgId:   result.OrgID,
+				Name:    fmt.Sprintf("alertmanager-%s", uid),
+				Type:    "alertmanager",
+				Access:  "proxy",
+				Url:     uri,
+				Created: time.Unix(result.CreatedAt, 0),
+				Updated: time.Unix(result.UpdatedAt, 0),
+				Uid:     uid,
+				Version: 1,
+				JsonData: simplejson.NewFromAny(map[string]interface{}{
+					"handleGrafanaManagedAlerts": true,
+					"implementation":             "prometheus",
+				}),
+				SecureJsonData: map[string][]byte{},
+			}
+
+			if u.User != nil {
+				ds.BasicAuth = true
+				ds.BasicAuthUser = u.User.Username()
+				if password, ok := u.User.Password(); ok {
+					ds.SecureJsonData = ualert.GetEncryptedJsonData(map[string]string{
+						"basicAuthPassword": password,
+					})
+				}
+			}
+
+			rowsAffected, err := sess.Table("data_source").Insert(ds)
+			if err != nil {
+				return err
+			}
+			if rowsAffected == 0 {
+				return fmt.Errorf("expected 1 row, got %d", rowsAffected)
+			}
+		}
+	}
+
+	return nil
+}
+
+func removeDuplicates(strs []string) []string {
+	var res []string
+	found := map[string]bool{}
+
+	for _, str := range strs {
+		if found[str] {
+			continue
+		}
+		found[str] = true
+		res = append(res, str)
+	}
+	return res
+}
+
+func generateNewDatasourceUid(sess *xorm.Session, orgId int64) (string, error) {
+	for i := 0; i < 3; i++ {
+		uid := util.GenerateShortUID()
+
+		exists, err := sess.Table("data_source").Where("uid = ? AND org_id = ?", uid, orgId).Exist()
+		if err != nil {
+			return "", err
+		}
+
+		if !exists {
+			return uid, nil
+		}
+	}
+
+	return "", datasources.ErrDataSourceFailedGenerateUniqueUid
+}

pkg/services/sqlstore/migrations/migrations.go

@@ -105,6 +105,8 @@ func (*OSSMigrations) AddMigration(mg *Migrator) {
 	accesscontrol.AddSeedAssignmentMigrations(mg)
 	accesscontrol.AddManagedFolderAlertActionsRepeatFixedMigration(mg)
 
+	AddExternalAlertmanagerToDatasourceMigration(mg)
+
 	// TODO: This migration will be enabled later in the nested folder feature
 	// implementation process. It is on hold so we can continue working on the
 	// store implementation without impacting any grafana instances built off