Alerting: Fix provenance guard checks for Alertmanager configuration to not cause panic when compared nested objects (#69009)

* fix current settings parsed as new
* replace map comparison with cmp.Diff and log the diff

pkg/services/ngalert/api/api_alertmanager_guards.go

@@ -9,6 +9,7 @@ import (
 	amConfig "github.com/prometheus/alertmanager/config"
 	"github.com/prometheus/alertmanager/pkg/labels"
 
+	"github.com/grafana/grafana/pkg/infra/log"
 	apimodels "github.com/grafana/grafana/pkg/services/ngalert/api/tooling/definitions"
 	ngmodels "github.com/grafana/grafana/pkg/services/ngalert/models"
 	"github.com/grafana/grafana/pkg/util/cmputil"
@@ -21,7 +22,7 @@ func (srv AlertmanagerSrv) provenanceGuard(currentConfig apimodels.GettableUserC
 	if err := checkTemplates(currentConfig, newConfig); err != nil {
 		return err
 	}
-	if err := checkContactPoints(currentConfig.AlertmanagerConfig.Receivers, newConfig.AlertmanagerConfig.Receivers); err != nil {
+	if err := checkContactPoints(srv.log, currentConfig.AlertmanagerConfig.Receivers, newConfig.AlertmanagerConfig.Receivers); err != nil {
 		return err
 	}
 	if err := checkMuteTimes(currentConfig, newConfig); err != nil {
@@ -67,7 +68,7 @@ func checkTemplates(currentConfig apimodels.GettableUserConfig, newConfig apimod
 	return nil
 }
 
-func checkContactPoints(currReceivers []*apimodels.GettableApiReceiver, newReceivers []*apimodels.PostableApiReceiver) error {
+func checkContactPoints(l log.Logger, currReceivers []*apimodels.GettableApiReceiver, newReceivers []*apimodels.PostableApiReceiver) error {
 	newCPs := make(map[string]*apimodels.PostableGrafanaReceiver)
 	for _, postedReceiver := range newReceivers {
 		for _, postedContactPoint := range postedReceiver.GrafanaManagedReceivers {
@@ -104,22 +105,15 @@ func checkContactPoints(currReceivers []*apimodels.GettableApiReceiver, newRecei
 				return err
 			}
 			newSettings := map[string]interface{}{}
-			err = json.Unmarshal(contactPoint.Settings, &newSettings)
+			err = json.Unmarshal(postedContactPoint.Settings, &newSettings)
 			if err != nil {
 				return err
 			}
-			if err != nil {
-				return err
-			}
-			for key, val := range existingSettings {
-				if newVal, present := newSettings[key]; present {
-					if val != newVal {
+			d := cmp.Diff(existingSettings, newSettings)
+			if len(d) > 0 {
+				l.Warn("Settings of contact point with provenance status cannot be changed via regular API.", "contactPoint", postedContactPoint.Name, "settingsDiff", d, "error", editErr)
 				return editErr
 			}
-				} else {
-					return editErr
-				}
-			}
 		}
 	}
 	return nil

pkg/services/ngalert/api/api_alertmanager_guards_test.go

@@ -9,6 +9,7 @@ import (
 	"github.com/prometheus/common/model"
 	"github.com/stretchr/testify/require"
 
+	"github.com/grafana/grafana/pkg/infra/log/logtest"
 	"github.com/grafana/grafana/pkg/services/ngalert/api/tooling/definitions"
 	"github.com/grafana/grafana/pkg/services/ngalert/models"
 )
@@ -277,7 +278,7 @@ func TestCheckContactPoints(t *testing.T) {
 			},
 		},
 		{
-			name:      "editing a provisioned object should fail",
+			name:      "editing secure settings of a provisioned object should fail",
 			shouldErr: true,
 			currentConfig: []*definitions.GettableApiReceiver{
 				defaultGettableReceiver(t, "test-1", models.ProvenanceAPI),
@@ -292,10 +293,24 @@ func TestCheckContactPoints(t *testing.T) {
 				}(),
 			},
 		},
+		{
+			name:      "editing settings of a provisioned object should fail",
+			shouldErr: true,
+			currentConfig: []*definitions.GettableApiReceiver{
+				defaultGettableReceiver(t, "test-1", models.ProvenanceAPI),
+			},
+			newConfig: []*definitions.PostableApiReceiver{
+				func() *definitions.PostableApiReceiver {
+					receiver := defaultPostableReceiver(t, "test-1")
+					receiver.GrafanaManagedReceivers[0].Settings = definitions.RawMessage(`{ "hello": "data", "data": { "test": "test"}}`)
+					return receiver
+				}(),
+			},
+		},
 	}
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			err := checkContactPoints(test.currentConfig, test.newConfig)
+			err := checkContactPoints(&logtest.Fake{}, test.currentConfig, test.newConfig)
 			if test.shouldErr {
 				require.Error(t, err)
 			} else {
@@ -320,7 +335,8 @@ func defaultGettableReceiver(t *testing.T, uid string, provenance models.Provena
 						"url": true,
 					},
 					Settings: definitions.RawMessage(`{
-						"hello": "world"
+						"hello": "world",
+						"data": {}
 					}`),
 				},
 			},
@@ -339,7 +355,8 @@ func defaultPostableReceiver(t *testing.T, uid string) *definitions.PostableApiR
 					Type:                  "slack",
 					DisableResolveMessage: true,
 					Settings: definitions.RawMessage(`{
-						"hello": "world"
+						"hello": "world",
+						"data" : {}
 					}`),
 				},
 			},