final String hostname = ComponentUtil.getSystemHelper().getHostname();
        final String targetName = ComponentUtil.getFessConfig().getSchedulerTargetName();

        final String body = toJson(Map.of( //
                "type", TYPE_HEARTBEAT, //
                "instanceId", instanceId, //
                "hostname", hostname, //

    }

    /**
     * Gets host information including hostname and IP address.
     *
     * @return formatted string containing hostname and IP address
     */
    protected String getHostInfo() {
        final StringBuilder buf = new StringBuilder();
        try {
            final InetAddress ia = InetAddress.getLocalHost();
            final String hostname = ia.getHostName();

    }

    /**
     * Gets the hostname of the local machine.
     *
     * @return The hostname.
     */
    public String getHostname() {
        final Map<String, String> env = getEnvMap();
        if (env.containsKey("COMPUTERNAME")) {
            return env.get("COMPUTERNAME");
        }
        if (env.containsKey("HOSTNAME")) {
            return env.get("HOSTNAME");
        }
        try {

{
    "properties": {
      "type": {
        "type": "keyword"
      },
      "instanceId": {
        "type": "keyword"
      },
      "hostname": {
        "type": "keyword"
      },
      "name": {
        "type": "keyword"
      },
      "status": {
        "type": "keyword"
      },
      "targetInstanceId": {
        "type": "keyword"
      },
      "data": {
        "type": "text",
        "index": false

{
  "properties": {
    "hostname": {
      "type": "keyword"
    },
    "level": {
      "type": "keyword"
    },
    "loggerName": {
      "type": "keyword"
    },
    "message": {
      "type": "text",
      "index": false
    },
    "throwable": {
      "type": "text",
      "index": false
    },
    "timestamp": {
      "type": "date",
      "format": "epoch_millis"
    }
  }

        }

        final int searchSize = fessConfig.getLogNotificationSearchSizeAsInteger();
        final String hostname = ComponentUtil.getSystemHelper().getHostname();
        final SearchResponse searchResponse = client.prepareSearch(indexName)
                .setQuery(QueryBuilders.termQuery("hostname", hostname))
                .setSize(searchSize)
                .addSort("timestamp", SortOrder.ASC)
                .execute()

        } finally {
            envMap.remove("COMPUTERNAME");
        }
        try {
            envMap.put("HOSTNAME", "yyy");
            assertEquals("yyy", systemHelper.getHostname());
        } finally {
            envMap.remove("HOSTNAME");
        }
    }

    @Test
    public void test_getInstanceId_withoutTargetName() {

        final InstanceInfo info = new InstanceInfo();
        info.instanceId = "node1@host1";
        info.hostname = "host1";
        info.name = "node1";
        info.lastSeen = 1000L;

        assertEquals("node1@host1", info.instanceId);
        assertEquals("host1", info.hostname);
        assertEquals("node1", info.name);
        assertEquals(1000L, info.lastSeen);
    }

    @Test

        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final String value = fessConfig.getPurgeByBots();
        String[] botNames;
        if (StringUtil.isBlank(value)) {
            botNames = StringUtil.EMPTY_STRINGS;
        } else {
            botNames = value.split(",");
        }

        final int batchSize = fessConfig.getSearchlogProcessBatchSizeAsInteger();

            }

            String hostname = fessConfig.getMailHostname();
            if (StringUtil.isBlank(hostname)) {
                hostname = ComponentUtil.getSystemHelper().getHostname();
            }
            dataMap.put("hostname", hostname);

            logger.debug("\ninfoMap: {}\ndataMap: {}", infoMap, dataMap);