Alerting: add collision safe update function for alertmanager configurations (#46692)

* Alerting: add collision safe update function for alertmanager configurations

* fix typo

* use bootstrap func for tests

* move hash calculation to store

* remove icons lol

* remove removed field

pkg/services/ngalert/store/alertmanager_test.go

@@ -0,0 +1,84 @@
+//go:build integration
+// +build integration
+
+package store
+
+import (
+	"context"
+	"crypto/md5"
+	"fmt"
+	"testing"
+
+	"github.com/grafana/grafana/pkg/services/ngalert/models"
+	"github.com/grafana/grafana/pkg/services/sqlstore"
+	"github.com/stretchr/testify/require"
+)
+
+func TestAlertManagerHash(t *testing.T) {
+	sqlStore := sqlstore.InitTestDB(t)
+	store := &DBstore{
+		SQLStore: sqlStore,
+	}
+	setupConfig := func(t *testing.T, config string) (string, string) {
+		config, configMD5 := config, fmt.Sprintf("%x", md5.Sum([]byte(config)))
+		err := store.SaveAlertmanagerConfiguration(context.Background(), &models.SaveAlertmanagerConfigurationCmd{
+			AlertmanagerConfiguration: config,
+			ConfigurationVersion:      "v1",
+			Default:                   false,
+			OrgID:                     1,
+		})
+		require.NoError(t, err)
+		return config, configMD5
+	}
+	t.Run("After saving the DB should return the right hash", func(t *testing.T) {
+		_, configMD5 := setupConfig(t, "my-config")
+		req := &models.GetLatestAlertmanagerConfigurationQuery{
+			OrgID: 1,
+		}
+		err := store.GetLatestAlertmanagerConfiguration(context.Background(), req)
+		require.NoError(t, err)
+		require.Equal(t, configMD5, req.Result.ConfigurationHash)
+	})
+
+	t.Run("When passing the right hash the config should be updated", func(t *testing.T) {
+		_, configMD5 := setupConfig(t, "my-config")
+		req := &models.GetLatestAlertmanagerConfigurationQuery{
+			OrgID: 1,
+		}
+		err := store.GetLatestAlertmanagerConfiguration(context.Background(), req)
+		require.NoError(t, err)
+		require.Equal(t, configMD5, req.Result.ConfigurationHash)
+		newConfig, newConfigMD5 := "my-config-new", fmt.Sprintf("%x", md5.Sum([]byte("my-config-new")))
+		err = store.UpdateAlertManagerConfiguration(&models.SaveAlertmanagerConfigurationCmd{
+			AlertmanagerConfiguration: newConfig,
+			FetchedConfigurationHash:  configMD5,
+			ConfigurationVersion:      "v1",
+			Default:                   false,
+			OrgID:                     1,
+		})
+		require.NoError(t, err)
+		err = store.GetLatestAlertmanagerConfiguration(context.Background(), req)
+		require.NoError(t, err)
+		require.Equal(t, newConfig, req.Result.AlertmanagerConfiguration)
+		require.Equal(t, newConfigMD5, req.Result.ConfigurationHash)
+	})
+
+	t.Run("When passing the wrong hash the update should error", func(t *testing.T) {
+		config, configMD5 := setupConfig(t, "my-config")
+		req := &models.GetLatestAlertmanagerConfigurationQuery{
+			OrgID: 1,
+		}
+		err := store.GetLatestAlertmanagerConfiguration(context.Background(), req)
+		require.NoError(t, err)
+		require.Equal(t, configMD5, req.Result.ConfigurationHash)
+		err = store.UpdateAlertManagerConfiguration(&models.SaveAlertmanagerConfigurationCmd{
+			AlertmanagerConfiguration: config,
+			FetchedConfigurationHash:  "the-wrong-hash",
+			ConfigurationVersion:      "v1",
+			Default:                   false,
+			OrgID:                     1,
+		})
+		require.Error(t, err)
+		require.EqualError(t, ErrVersionLockedObjectNotFound, err.Error())
+	})
+}