public void toServiceHierarchyRelation(String upperServiceName,
                                           Layer upperServiceLayer,
                                           String lowerServiceName,
                                           Layer lowerServiceLayer) {
        if (!this.isEnableHierarchy) {
            return;
        }
        Map<String, HierarchyDefinitionService.MatchingRule> lowerLayers = getHierarchyDefinition().get(upperServiceLayer.name());
        if (lowerLayers == null || !lowerLayers.containsKey(lowerServiceLayer.name())) {
            log.error("upperServiceLayer " + upperServiceLayer.name() + " or lowerServiceLayer " + lowerServiceLayer.name()
                          + " is not defined in hierarchy-definition.yml.");
            return;
        }
        autoMatchingServiceRelation(upperServiceName, upperServiceLayer, lowerServiceName, lowerServiceLayer);
    }
Build the hierarchy relation between the 2 services. the `serviceLayer` and `relatedServiceLayer` hierarchy
relations should be defined in `config/hierarchy-definition.yml`.

@param upperServiceName         the name of the service
@param upperServiceLayer        the layer of the service
@param lowerServiceName  the name of the lower service
@param lowerServiceLayer the layer of the lower service
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/hierarchy/HierarchyService.java