Yuna (ユウナ)

The extra Zookeeper support for Illyria client pool.

Installation

$ npm install --save yuna

Yuna is a summoner embarking on a journey to defeat the world-threatening monster Sin. And in this project, she will summon multiple connections of illyria to defeat the instability of servers.

Usage

Create

First of all, you should create a new Yuna object.

var Yuna = require("yuna");
var yuna = Yuna.createPool(ZOOKEEPER_CONNECT_STRING, ZOOKEEPER_ROOT, ZOOKEEPER_PREFIX, OPTIONS);

Attention: all of the params above in Yuna.createPool are optional.

The parameters and their default value are shown below.

| Parameter | Default | Description | |------------------------------|-----------------|--------------------------------------------------------------------------------------| | ZOOKEEPER_CONNECT_STRING | "127.0.0.1" | The connect string for zookeeper. | | ZOOKEEPER_ROOT | "/illyria" | The root path for the certain server nodes. | | ZOOKEEPER_PREFIX | "/HB_" | The prefix for the certain server nodes. | | OPTIONS | [object Object] | The options for this pool. | | OPTIONS.maxPool | 10 | The maximum client count in the pool. | | OPTIONS.runTimeout | 10000 | Timeout for one sending operation in million second. (not including retry) | | OPTIONS.connectTimeout | 5000 | Timeout for the connecting to the server in million second. | | OPTIONS.retryForGetting | 5 | Times of retry for getting a usable connection. | | OPTIONS.gettingRetryInterval | 200 | Interval for retry of getting a usable connection. | | OPTIONS.zookeeper | {} | Refer to Illyria document. | | OPTIONS.? | - | Refer to io.js document. |

Tip: don't include connectString, root and prefix in option OPTIONS.zookeeper because it will be replaced by ZOOKEEPER_CONNECT_STRING, ZOOKEEPER_ROOT and ZOOKEEPER_PREFIX.

Send

The main method you should use in your program is Yuna::send. The parameters are the same as Illyria Client.

yuna.send("module", "method", DATA, function(err, data, conn) {
    // `conn` is the current connection
    console.log(err, data, conn);
});

Cast

Using cast protocol to send the message. Reference to Illyria Client.

yuna.cast("module", "method", DATA, function(err, data, conn) {
    // `conn` is the current connection
    // and data will always be `undefined`
    console.log(err, data, conn);
});

Destroy

Destroy this Yuna pool and disconnect all the connections.

yuna.destroy();

New Connection

Most time you needn't to use this method. It usually be used by other functions of Yuna like the constructor function.

yuna.newConnection([force], callback);

The optional parameter force is defined to tell the function weather the connection will be created forcely and ignore the maximum connection count of the pool.

The callback function is look like function(err, conn) {}.

Get Connection

Most time you needn't to use this method. This method will return you a usable Illyria connection just now if you really want to do this.

yuna.getConnection(function(err, conn) {
    // DO SOMETHING
});

Available Connection Count

Get current available connection count.

var availables = yuna.availableCount();

Client Position

Most time you needn't to use this method. It will tell the position of the connection you passed in in the connection pool.

var idx = yuna.clientPosition(conn);

Events

new

This event will be emitted when a new connection is set.

yuna.on("new", function() {
    // SOME CODE...
});

error

This event will be emitted when a connection has an error. (But Yuna will reconnect automatically)

yuna.on("error", function() {
    // SOME CODE...
});

close

This event will be emitted when a connection is disconnected.

yuna.on("close", function() {
    // SOME CODE...
});

Contribution

You're welcome to make pull requests.

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