Alerting: Add image URI annotation only when there's an image (#69825)

* Alerting: Add image URI annotation only when there's an image

* fix function name (changed on main branch)

pkg/services/ngalert/state/compat.go

@@ -49,7 +49,10 @@ func StateToPostableAlert(alertState *State, appURL *url.URL) *models.PostableAl
 	}
 
 	if alertState.Image != nil {
-		nA[alertingModels.ImageTokenAnnotation] = generateImageURI(alertState.Image)
+		imageURI := generateImageURI(alertState.Image)
+		if imageURI != "" {
+			nA[alertingModels.ImageTokenAnnotation] = imageURI
+		}
 	}
 
 	if alertState.StateReason != "" {
@@ -174,5 +177,9 @@ func generateImageURI(image *ngModels.Image) string {
 	if image.URL != "" {
 		return image.URL
 	}
-	return "token://" + image.Token
+	if image.Token != "" {
+		return "token://" + image.Token
+	}
+
+	return ""
 }

pkg/services/ngalert/state/compat_test.go

@@ -133,6 +133,21 @@ func Test_StateToPostableAlert(t *testing.T) {
 
 					require.Equal(t, expected, result.Annotations)
 				})
+
+				t.Run("don't add __alertImageToken__ if there's no image token", func(t *testing.T) {
+					alertState := randomState(tc.state)
+					alertState.Annotations = randomMapOfStrings()
+					alertState.Image = &ngModels.Image{}
+
+					result := StateToPostableAlert(alertState, appURL)
+
+					expected := make(models.LabelSet, len(alertState.Annotations)+1)
+					for k, v := range alertState.Annotations {
+						expected[k] = v
+					}
+
+					require.Equal(t, expected, result.Annotations)
+				})
 			})
 
 			t.Run("should add state reason annotation if not empty", func(t *testing.T) {