check if labels are nil before adding labels

pkg/app/compose.go

@@ -16,7 +16,7 @@ func SetRecipeLabel(compose *composetypes.Config, stackName string, recipe strin
 		if service.Name == "app" {
 			log.Debugf("set recipe label 'coop-cloud.%s.recipe' to %s for %s", stackName, recipe, stackName)
 			labelKey := fmt.Sprintf("coop-cloud.%s.recipe", stackName)
-			service.Deploy.Labels[labelKey] = recipe
+			AddLabel(service, labelKey, recipe)
 		}
 	}
 }
@@ -28,7 +28,7 @@ func SetChaosLabel(compose *composetypes.Config, stackName string, chaos bool) {
 		if service.Name == "app" {
 			log.Debugf("set label 'coop-cloud.%s.chaos' to %v for %s", stackName, chaos, stackName)
 			labelKey := fmt.Sprintf("coop-cloud.%s.chaos", stackName)
-			service.Deploy.Labels[labelKey] = strconv.FormatBool(chaos)
+			AddLabel(service, labelKey, strconv.FormatBool(chaos))
 		}
 	}
 }
@@ -39,7 +39,7 @@ func SetChaosVersionLabel(compose *composetypes.Config, stackName string, chaosV
 		if service.Name == "app" {
 			log.Debugf("set label 'coop-cloud.%s.chaos-version' to %v for %s", stackName, chaosVersion, stackName)
 			labelKey := fmt.Sprintf("coop-cloud.%s.chaos-version", stackName)
-			service.Deploy.Labels[labelKey] = chaosVersion
+			AddLabel(service, labelKey, chaosVersion)
 		}
 	}
 }
@@ -56,7 +56,7 @@ func SetUpdateLabel(compose *composetypes.Config, stackName string, appEnv envfi
 			}
 			log.Debugf("set label 'coop-cloud.%s.autoupdate' to %s for %s", stackName, enable_auto_update, stackName)
 			labelKey := fmt.Sprintf("coop-cloud.%s.autoupdate", stackName)
-			service.Deploy.Labels[labelKey] = enable_auto_update
+			AddLabel(service, labelKey, enable_auto_update)
 		}
 	}
 }
@@ -86,3 +86,10 @@ func GetTimeoutFromLabel(compose *composetypes.Config, stackName string) (int, e
 	}
 	return timeout, err
 }
+
+func AddLabel(service composetypes.ServiceConfig, labelKey string, value string) {
+	if service.Deploy.Labels == nil {
+		service.Deploy.Labels = composetypes.Labels{}
+	}
+	service.Deploy.Labels[labelKey] = value
+}