URL

URL generator for OpenTSDB HTTP data requests.

Install

For use in Node.js,

$ npm install opentsdb-url

For use in the browser, use browserify.

Usage

To use the module,

var createFactory = require( 'opentsdb-url' );

A URL generator must be bound to a particular OpenTSDB client instance.

var createClient = require( 'opentsdb-client' );

// Create a new client:
var client = createClient();

// Bind the generator to the client:
var url = createFactory( client );

The instance has the following methods...

url.template()

Creates a URL template based on the OpenTSDB client configuration. The template contains two parameters: start and end.

url.template();

Note: this method does not provide public access to the URL template. Instead, the method returns the current URL generator instance.

url.create()

Inserts start and end times into a template OpenTSDB query string. The start and end times are obtained from the bound client instance.

url.create();
// returns '...'

Note: Ensure that you have first generated a template before trying to create a URL.

The motivation for the template/create separation is the recognition that start and end times are more likely to change than other client parameters, particularly when periodically polling OpenTSDB for data belonging to the same metric.

Examples

var createClient = require( 'opentsdb-client' ),
	mQuery = require( 'opentsdb-mquery' ),
	createFactory = require( 'opentsdb-url' ),
	end = Date.now(),
	start = end - 1000,
	client,
	query,
	url;

// Create a new metric query and configure:
query = mQuery();

query.metric( 'cpu.utilization' )
	.tags( 'beep', 'boop' );

// Create a new client and configure:
client = createClient();

client.queries( query );

// Bind the client to a URL generator:
url = createFactory( client );

// Create the url template:
url.template();

// Periodically create new URLs...
for ( var i = 0; i < 10; i++ ) {
	setTimeout( createURL( i*1000 ), i*1000 );
}

function createURL( offset ) {
	var begin = start + offset,
		stop = end + offset;
	return function onTimeout() {
		client.start( begin )
			.end( stop );

		console.log( url.create() );
	};
}

To run the example code from the top-level application directory,

$ node ./examples/index.js

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.

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Copyright

Copyright © 2014. Athan Reines.