TypeScript Consumer.on方法代碼示例

    return new Observable(o => {
      consumer.on('message', m => {
        if (m.value === '__done') {
          return o.complete();
        }
        o.next(m.value)
      });
      consumer.on('error', err => o.error(err));

      return () => consumer.close(() => {});
    });

  kit('publishes to a kafka topic', (done) => {
    let topic = 'gustavTest-publish';

    let consumer = new kafka.Consumer(client, [{
      topic
    }]);

    let obs = new Observable(o => {
      setTimeout(() => o.next('hello'), 15);
    });

    gr.to(topic, obs);

    consumer.on('message', (message) => {
      expect(message.value).to.equal('hello');
      done();
    });
  });

  /**
   * Restore the system by re-reading Kafka messages.
   * This base implementation restores documents from a set of
   * ArangoDB database collections, using the chassis-srv database provider.
   * @param topics list of Kafka topics to be restored
   */
  async restore(payload: any): Promise<any> {
    if (_.isEmpty(payload) || _.isEmpty(payload.data)) {
      throw new errors.InvalidArgument('Invalid payload for restore command');
    }

    const restoreData: RestoreData[] = payload.data || [];

    // the Kafka config should contains a key-value pair, mapping
    // a label with the topic's name
    const kafkaEventsCfg = this.config.events.kafka;
    const kafkaCfg = this.config.events.kafka.topics;
    if (_.isNil(kafkaCfg) || kafkaCfg.length == 0) {
      throw new errors.Internal('Kafka topics config not available');
    }

    const topicLabels = _.keys(kafkaCfg).filter((elem, index) => {
      return elem.includes('.resource');
    }).map((elem) => {
      return elem.replace('.resource', '');
    });

    const restoreSetup = {};
    const restoreEventSetup = {};

    restoreData.forEach((data) => {
      const ignoreOffset = (data.ignore_offset || []).filter((offset) => {
        const isNumber = Number(offset) != NaN;
        if (!isNumber) {
          this.logger.warn(`Invalid value for "ignore_offset" parameter in restore: ${offset}`);
        }
        return isNumber;
      });
      restoreSetup[data.entity] = {
        baseOffset: Number(data.base_offset) || 0,
        ignoreOffset
      };
    });

    const restoreCollections = _.keys(restoreSetup);

    try {
      const dbCfgs = this.config.database;
      const dbCfgNames = _.keys(dbCfgs);
      for (let i = 0; i < dbCfgNames.length; i += 1) {
        const dbCfgName = dbCfgNames[i];
        const dbCfg = dbCfgs[dbCfgName];
        const collections = dbCfg.collections;
        let graphName;
        if (this.config.graph) {
          graphName = this.config.graph.graphName;
        }
        const db = await database.get(dbCfg, this.logger, graphName);

        if (_.isNil(collections)) {
          this.logger.warn('No collections found on DB config');
          return {};
        }

        let intersection: string[] = _.intersection(restoreCollections, collections);
        if (intersection.length > 0) {
          intersection = _.intersection(intersection, topicLabels);
          for (let resource of intersection) {
            const topicName = kafkaCfg[`${resource}.resource`].topic;
            restoreEventSetup[topicName] = {
              topic: this.kafkaEvents.topic(topicName),
              events: this.makeResourcesRestoreSetup(db, resource),
              baseOffset: restoreSetup[resource].baseOffset,
              ignoreOffset: restoreSetup[resource].ignoreOffset
            };
          }
        }
      }

      if (_.isEmpty(restoreEventSetup)) {
        this.logger.warn('No data was setup for the restore process.');
      } else {
        const that = this;
        // Start the restore process
        this.logger.warn('restoring data');

        for (let topicName in restoreEventSetup) {
          const topicSetup: any = restoreEventSetup[topicName];
          const restoreTopic: Topic = topicSetup.topic;
          const topicEvents: any = topicSetup.events;

          // saving listeners for potentially subscribed events on this topic,
          // so they don't get called during the restore process
          const previousEvents: string[] = _.cloneDeep(restoreTopic.subscribed);
          const listenersBackup = new Map<string, Function[]>();
          for (let event of previousEvents) {
            listenersBackup.set(event, (restoreTopic.emitter as EventEmitter).listeners(event));
            await restoreTopic.removeAllListeners(event);
          }

//.........這裏部分代碼省略.........