hiot-kafka/lib/broker/envelope.js

hiot-app middleware to bootstrap kafka

"use strict";

exports.parse = (consumer, payload, topic, partition, logger) => {
  var message = payload.message;
  var value;

  var reject = commit(consumer, topic, partition, payload.offset, "rejected");
  var ack = commit(consumer, topic, partition, payload.offset, "acknowledge");

  if (!message || !message.value) {
    logger.warn("rejecting message due to empty body");
    return reject();
  }

  try {
    var json = message.value.toString("utf8");
    value = JSON.parse(json);
  } catch (err) {
    logger.error({ json }, "rejecting message due to invalid json");
    return reject();
  }

  return Promise.resolve({
    topic: topic,
    partition: partition,
    offset: payload.offset,
    message: {
      key: message.key,
      value: value,
    },
    ack: ack,
    reject: reject,
  });
};

function commit(consumer, topic, partition, offset, reason) {
  var meta = { topic, partition, offset, metadata: reason };
  return consumer.commitOffset.bind(consumer, meta);
}