public ScaleRuleDO getRuleByMetricName(final String metricName) {
        return ruleCache.get(metricName);
    }
getRuleByMetricName.

@param metricName metricName
@return ScaleRuleDO
shenyu-admin/src/main/java/org/apache/shenyu/admin/scale/monitor/subject/cache/ScaleRuleCache.java