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编辑当前文件:/home/freeclou/app.optimyar.com/backend/node_modules/mongodb/lib/core/sdam/srv_polling.js

'use strict';

class SrvPollingEvent {
  constructor(srvRecords) {
    this.srvRecords = srvRecords;
  }

addresses() {
    return new Set(this.srvRecords.map(record => `${record.name}:${record.port}`));
  }
}

class SrvPoller extends EventEmitter {
  /**
   * @param {object} options
   * @param {string} options.srvHost
   * @param {number} [options.heartbeatFrequencyMS]
   * @param {function} [options.logger]
   * @param {string} [options.loggerLevel]
   */
  constructor(options) {
    super();

if (!options || !options.srvHost) {
      throw new TypeError('options for SrvPoller must exist and include srvHost');
    }

this.srvHost = options.srvHost;
    this.rescanSrvIntervalMS = 60000;
    this.heartbeatFrequencyMS = options.heartbeatFrequencyMS || 10000;
    this.logger = Logger('srvPoller', options);

this.haMode = false;
    this.generation = 0;

this._timeout = null;
  }

get srvAddress() {
    return `_mongodb._tcp.${this.srvHost}`;
  }

get intervalMS() {
    return this.haMode ? this.heartbeatFrequencyMS : this.rescanSrvIntervalMS;
  }

start() {
    if (!this._timeout) {
      this.schedule();
    }
  }

stop() {
    if (this._timeout) {
      clearTimeout(this._timeout);
      this.generation += 1;
      this._timeout = null;
    }
  }

schedule() {
    clearTimeout(this._timeout);
    this._timeout = setTimeout(() => this._poll(), this.intervalMS);
  }

success(srvRecords) {
    this.haMode = false;
    this.schedule();
    this.emit('srvRecordDiscovery', new SrvPollingEvent(srvRecords));
  }

failure(message, obj) {
    this.logger.warn(message, obj);
    this.haMode = true;
    this.schedule();
  }

parentDomainMismatch(srvRecord) {
    this.logger.warn(
      `parent domain mismatch on SRV record (${srvRecord.name}:${srvRecord.port})`,
      srvRecord
    );
  }

_poll() {
    const generation = this.generation;
    dns.resolveSrv(this.srvAddress, (err, srvRecords) => {
      if (generation !== this.generation) {
        return;
      }

if (err) {
        this.failure('DNS error', err);
        return;
      }

if (!finalAddresses.length) {
        this.failure('No valid addresses found at host');
        return;
      }

this.success(finalAddresses);
    });
  }
}

module.exports.SrvPollingEvent = SrvPollingEvent;
module.exports.SrvPoller = SrvPoller;