Socket

OpenTSDB socket client.

OpenTSDB provides three methods of writing data: telnet, HTTP, and batch import. This library implements a telnet interface for writing data.

A few words on the other methods:

• Batch import is a command-line interface which is useful for data migrations.
• The HTTP interface provides the convenience of REST but has performance limitations.

Install

For use in Node.js,

$ npm install opentsdb-socket

For use in the browser, use browserify.

Client

To interface with OpenTSDB, one must first create a socket client. To do so,

var createSocket = require( 'opentsdb-socket' );

var socket = createSocket();

OpenTSDB socket clients are configurable and have the following methods...

socket.host( [host] )

This method is a setter/getter. If no host is provided, the method returns the configured host. By default, the client host is 127.0.0.1. To point to a remote host,

socket.host( '192.168.92.11' );

socket.port( [port] )

This method is a setter/getter. If no port is provided, the method returns the configured port. By default, the client port is 4242. To set a different port,

socket.port( 8080 );

socket.connect()

Creates a TCP socket connection.

socket.connect();

socket.status()

Returns the current connection status. If a socket connection exists, returns true. If no socket connection exists, returns false.

socket.status();

socket.strict( [bool] )

This method is a setter/getter. If no boolean flag is provided, the method returns the strict setting. By default, the socket enforces strict type checking on socket writes. To turn off strict mode,

socket.strict( false );

Turn off strict mode when you are certain that arguments provided to the socket.write() method are of the proper type.

socket.write( string[, clbk] )

Writes to the socket connection. If strict mode is off, no type checking of input arguments occurs. An optional callback is invoked after writing all data to the socket. To write to the socket,

var value = '';

value += 'put ';
value += 'cpu.utilization ';
value += Date.now() + ' ';
value += Math.random() + ' ';
value += 'beep=boop ';
value += 'foo=bar\n';

socket.write( value, function ack() {
	console.log( '...data written...' );
});

socket.end()

Closes a socket connection. To close a socket,

socket.end();

Events

The socket is an event-emitter and emits the following events...

'connect'

The socket emits a connect event upon successfully establishing a socket connection. To register a listener,

socket.addListener( 'connect', function onConnect() {
	console.log( '...connected...' );
});

'error'

The socket emits an error event upon encountering an error. To register a listener,

socket.addListener( 'error', function onError( error ) {
	console.error( error.message );
	console.error( error.stack );
});

'close'

The socket emits a close event when the other end of the connection closes the socket. To register a listener,

socket.addListener( 'close', function onClose() {
	console.log( '...socket closed...' );
	console.log( '...attempting to reconnect in 5 seconds...' );
	setTimeout( function reconnect() {
		socket.connect();
	}, 5000 );
});

'warn'

The socket emits a warn event when attempting to create a new socket connection when a connection already exists. To register a listener,

socket.addListener( 'warn', function onWarn( message ) {
	console.warn( message );
});

Notes

When used as setters, all setter/getter methods are chainable. For example,

var createSocket = require( 'opentsdb-socket' ),
	socket = createSocket();

socket
	.host( '192.168.92.111' )
	.port( 8080 )
	.strict( false )
	.connect();

Examples

var createSocket = require( 'opentsdb-socket' ),
	socket = createSocket();

socket
	.host( '192.168.92.111' )
	.port( 4243 )
	.strict( false );

socket.on( 'error', onError );
socket.on( 'close', onClose );
socket.on( 'connect', onConnect );

connect();

function connect() {
	socket.connect();
}

function onError( error ) {
	console.error( error.message );
	console.error( error.stack );
}

function onClose() {
	console.log( '...attempting to reconnect in 2 seconds...' );
	setTimeout( function reconnect() {
		connect();
	}, 2000 );
}

function onConnect() {
	for ( var i = 0; i < 100; i++ ) {
		write( i );
	}
}

function write( idx ) {
	setTimeout( function onTimeout() {
		if ( socket.status() ) {
			socket.write( newLine(), onWrite );
		}
	}, 1000*idx );
}

function newLine() {
	var metric = 'cpu.utilization',
		timestamp = Date.now(),
		value = Math.random(),
		line = '';

	line += 'put ';
	line += metric + ' ';
	line += timestamp + ' ';
	line += value + ' ';
	line += 'beep=boop ';
	line += 'foo=bar';
	line += '\n';

	return line;
}

function onWrite() {
	console.log( '...data written to socket...' );
}

Tests

Unit

Unit tests use the Mocha test framework with Chai assertions. To run the tests, execute the following command in the top-level application directory:

$ make test

All new feature development should have corresponding unit tests to validate correct functionality.

Test Coverage

This repository uses Istanbul as its code coverage tool. To generate a test coverage report, execute the following command in the top-level application directory:

$ make test-cov

Istanbul creates a ./reports/coverage directory. To access an HTML version of the report,

$ make view-cov

License

MIT license.

Copyright

Copyright © 2014. Athan Reines.