private String getProperty(
      String target, String defaultValue, Properties properties, boolean isConfigNode) {
    return Optional.ofNullable(
            properties.getProperty((isConfigNode ? "cn_" : "dn_") + target, defaultValue))
        .map(String::trim)
        .orElse(defaultValue);
  }
Get property from confignode or datanode.
iotdb-core/metrics/interface/src/main/java/org/apache/iotdb/metrics/config/MetricConfigDescriptor.java