.put("processors", fessConfig.getCrawlerHttpProcessors())
                .put("http.heartbeat_interval", fessConfig.getFesenHeartbeatInterval());
        final String username = fessConfig.getFesenUsername();
        final String password = fessConfig.getFesenPassword();
        if (StringUtil.isNotBlank(username) && StringUtil.isNotBlank(password)) {
            builder.put(Constants.FESEN_USERNAME, username);

            return value;
        }
        return get("elasticsearch.http.ssl.certificate_authorities");
    }

    String getSearchEngineUsername();

    default String getFesenUsername() {
        final String value = getSearchEngineUsername();
        if (value != null) {
            return value;
        }
        return get("elasticsearch.username");
    }

                .put("processors", fessConfig.availableProcessors())
                .put("http.heartbeat_interval", fessConfig.getFesenHeartbeatInterval());
        final String username = fessConfig.getFesenUsername();
        final String password = fessConfig.getFesenPassword();
        if (StringUtil.isNotBlank(username) && StringUtil.isNotBlank(password)) {
            builder.put(Constants.FESEN_USERNAME, username);