callosum-client-tcp

Stability: 1 - Experimental

TCP Client for Callosum: a self-balancing distributed services protocol.

Usage

var CallosumClient = require('callosum-client-tcp');
var callosumClient = new CallosumClient({MAX_SLOTS: 100});
 
callosumClient.on('error', function (error) {
    console.log(error);
});
 
// add a connection to the connection pool
// client will either hang on to the connection or close it if it is not needed
callosumClient.newConnection(slot, socket);
 
var socket = callosumClient.getConnection();
// socket is either a connection that is available or undefined
 
callosumClient.returnConnection(socket);
// return a previously leased connection to the client pool
 

Tests

npm test

Overview

TCP Client for Callosum: a self-balancing distributed services protocol. It servers as a connection pool.

Open available connections are maintained internally via two heap data structures. The min heap data structure is maintained in order to provide a connection from the pool with the lowest slot value. The max heap data structure is maintained in order to enable rapid checking and replacing of a connection with a high slot value if a new connection with a lower slot value becomes available.

Documentation

CallosumClient

Public API

• new CallosumClient([options])
• callosumClient.getConnection()
• callosumClient.newConnection(slot, socket)
• callosumClient.returnConnection(socket)

new CallosumClient([options])

• options: Object (Default: {})
  • MAX_SLOTS: Integer (Default: 100) Number of connection slots to maintain.

Creates a new instance of CallosumClient.

callosumClient.getConnection()

• Return: Socket object
  • _destroyed: Boolean CAUTION: reserved for internal use
  • _destroySocket: Function CAUTION: reserved for internal use
  • _leased: Boolean CAUTION: reserved for internal use
  • _slot: Integer CAUTION: reserved for internal use

Returns next available socket with lowest slot number. If no sockets are available, undefined is returned.

callosumClient.insertSocket(slot, socket)

CAUTION: reserved for internal use

• slot: Integer Slot number.
• socket: Socket object Socket.

Internal bookkeeping of the socket via a min heap and a max heap with event listeners for socket destruction.

callosumClient.newConnection(slot, socket)

• slot: Integer Slot number.
• socket: Socket object Socket.

New connection (from a rover) is available for the client to keep or discard.

callosumClient.returnConnection(socket)

• socket: Socket object
  • _destroyed: Boolean CAUTION: reserved for internal use
  • _destroySocket: Function CAUTION: reserved for internal use
  • _leased: Boolean CAUTION: reserved for internal use
  • _slot: Integer CAUTION: reserved for internal use

When the user of the socket is finished with it, instead of closing it, this method allows the socket to be handed back to Callosum.