ZKConfig Client Node

A node client for zookeeper config system. You can refer the server here

Features

• Read config from remote server.
• Multi types, such as json, properties, yaml.
• Config watcher,
• Low CPU, based on zookeeper, lower CPU.
• Failover, config replica via zookeeper system and read config from local file system in case of all servers went down.
• Easy config with admin web ui.

How to use?

It is easy to use this.

npm install zkconfig-client-node

In your node code:

var ZKConfig = require('zkconfig-client-node');

var client = new ZKConfig.Client('127.0.0.1:2181', {
  path: '/zkconfig/config/dev',
  monitor: true,
  monitorPath: '/zkconfig/connection',
  username: 'zkconfig',
  password: 'zkconfig'
});
client.on('connected', function() {
  // connected
  console.info('connected');
});
client.on('data', function(config) {
  // get a config object.
  console.info('name: ' + config.get('name'));
});
client.connect();

API

The ZKConfig client has three important object: Client, Parser, Config.
Client is the main object that communicate with the zookeeper server.
Parser is an object to convert string content to a Config instance.
Config is an object to store data that loaded from server by a Client object.

Client

• constructor(servers, options): the construct function.

  servers: the zookeeper servers, seperated by ,.
  options: the options for the client.
  path: String, required. The path to store the config.

  • monitor: Boolean, optional. Whether to uploat the connection information.
  • monitorPath: String, optional. The path to sotre the connection information, must be the same with zkserver's connectionPath. if monitor is true, this parameter must be an existed path in zookeeper server.
  • username: String, optional. username for auth.
  • password: String, opational, password for auth.
  • scheme: String, optional, default "digest".
  • parser: string or a parser instance, optional, default is PropertiesParser.
  • More other options please refer to node-zookeeper-client

• connect(): connect to zookeeper server and emit a connected event when connect success.
• close(): release the connection.
• on(eventName, callback): register an event handler.
• off(eventName, callback): unreigster an event handler.
• event: the client instance will emit those events:
  • connect: fire while connect successfully.
  • data: the data loaded and parsed successfully.
  • error: the data loaded fail, parsed fail or fail to create connection to the server.

Parser

A parser to parse an string content to a config instance.

• parse(String content, callback)
  • content, a string content from zookeeper server.
  • callback, function(err: Error, config : Config), a config instance, if parse fail or content is full, config will return null. There are three parser:
• JsonParser, parser for json content.
• PropertiesParser, parser for java properties file.
• YamlParser, parser for yaml content.
• register, register a parser
  • key, the name of parser, eg: json, properties
  • factory, the factory of a parser, return a Parser instance.

Config

A instance to store data with convinient method to get data.

• get(path, defaultValue)
• getString(path, defaultValue)
• getInteger(path, defaultValue)
• getObject(path, defaultValue)
• getFloat(path, defaultValue)
• getList(path, defaultValue)
• forEach(path, callback), iterate particular path of value, then call the callback function. The callback function receive three parameter(value, key, config):one for value, one for key(index for array), the last one is the whole object that found. If nothing is found with the path, the callback will not be called.
• getContent(), get the string content.
• getValue(), get the object that store the data.

LICENSE

MIT