四好公路
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 

114 lines
3.0 KiB

'use strict';
var util = require('util');
var async = require('async');
var EventEmitter = require('events');
function Offset (client) {
EventEmitter.call(this);
var self = this;
this.client = client;
this.ready = this.client.ready;
this.client.on('ready', function () {
self.ready = true;
self.emit('ready');
});
this.client.once('connect', function () {
self.emit('connect');
});
this.client.on('error', function (err) {
self.emit('error', err);
});
}
util.inherits(Offset, EventEmitter);
Offset.prototype.fetch = function (payloads, cb) {
if (!this.ready) {
this.once('ready', () => this.fetch(payloads, cb));
return;
}
this.client.sendOffsetRequest(this.buildPayloads(payloads), cb);
};
Offset.prototype.buildPayloads = function (payloads) {
return payloads.map(function (p) {
p.partition = p.partition || 0;
p.time = p.time || Date.now();
p.maxNum = p.maxNum || 1;
p.metadata = 'm'; // metadata can be arbitrary
return p;
});
};
Offset.prototype.commit = function (groupId, payloads, cb) {
if (!this.ready) {
this.once('ready', () => this.commit(groupId, payloads, cb));
return;
}
this.client.sendOffsetCommitRequest(groupId, this.buildPayloads(payloads), cb);
};
Offset.prototype.fetchCommits = function (groupId, payloads, cb) {
if (!this.ready) {
this.once('ready', () => this.fetchCommits(groupId, payloads, cb));
return;
}
this.client.sendOffsetFetchRequest(groupId, this.buildPayloads(payloads), cb);
};
Offset.prototype.fetchLatestOffsets = function (topics, cb) {
fetchOffsets(this, topics, cb, -1);
};
Offset.prototype.fetchEarliestOffsets = function (topics, cb) {
fetchOffsets(this, topics, cb, -2);
};
// private helper
function fetchOffsets (offset, topics, cb, when) {
if (!offset.ready) {
if (when === -1) {
offset.once('ready', () => offset.fetchLatestOffsets(topics, cb));
} else if (when === -2) {
offset.once('ready', () => offset.fetchEarliestOffsets(topics, cb));
}
return;
}
async.waterfall([
callback => {
offset.client.loadMetadataForTopics(topics, callback);
},
(topicsMetaData, callback) => {
var payloads = [];
var metaDatas = topicsMetaData[1].metadata;
Object.keys(metaDatas).forEach(function (topicName) {
var topic = metaDatas[topicName];
Object.keys(topic).forEach(function (partition) {
payloads.push({
topic: topicName,
partition: partition,
time: when
});
});
});
if (payloads.length === 0) {
return callback(new Error('Topic(s) does not exist'));
}
offset.fetch(payloads, callback);
},
function (results, callback) {
Object.keys(results).forEach(function (topicName) {
var topic = results[topicName];
Object.keys(topic).forEach(function (partitionName) {
topic[partitionName] = topic[partitionName][0];
});
});
callback(null, results);
}
], cb);
}
module.exports = Offset;