cyclone

cyclone

Write Storm topologies in JavaScript.

Basic Example

import WordCount from './wordcount';
import SplitSentence from './splitsentence';
import RandomSentence from './randomsentence';
import Cyclone, { TopologyBuilder } from 'cyclone';


let builder = new TopologyBuilder();
builder.setSpout('spout', new RandomSentence());
builder.setBolt('split', new SplitSentence(), 4).shuffleGrouping('spout');
builder.setBolt('count', new WordCount(), 4).fieldsGrouping('split', [ 'word' ]);


Cyclone.run(builder, { name: 'mytopology' });

Spouts

To write a Spout, merely extend the provided Spout class and write your own implementation.

import { Spout } from 'cyclone';

export default class RandomSentence extends Spout {

	declareOutputFields() {
		return [ 'sentence' ];
	}

	nextTuple() {
		let rand = Math.floor(Math.random() * SENTENCES.length);
        this.emit({ tuple: [ SENTENCES[rand] ], anchorTupleId: id });
        done();
	}
}

Default Methods

• log

• emit

Overridable Methods

• declareOutputFields() (optional, defaults to [])

• getComponentConfiguration() (optional, defaults to {})

• nextTuple(id, done) (required)

• ack(id, done) (optional)

• fail(id, done) (optional)

Bolts

Similar to Spouts, Bolts are created by extending the provided Bolt base class.

import { Bolt } from 'cyclone';

export default class MyBolt extends Bolt {

	declareOutputFields() {
		return [ 'words' ];
	}

	process(tuple, done) {
		let [ sentence ] = tuple.values;
		let words = sentence.split(/\s+/);

        for (let word of words) {
            this.emit({ tuple: [ word ], anchorTupleId: tuple.id });
        }

        done();
	}

}

Default Methods

• log

• emit

Overridable Methods

• declareOutputFields() (optional, defaults to [])

• getComponentConfiguration() (optional, defaults to {})

• prepare(config, context, done) (optional)

• process(tuple, done) (required)

Running a local cluster

To run a local cluster simply run your topology file with the --local flag. For example, if the Basic Example above were your index.js file, simply run $ node . --local. You will need Apache Storm installed and on your path as well as an invocation of run in your topology file:

Cyclone.run(builder, { name: 'mytopology' });

Submitting a Topology

To submit a topology you will need Apache Storm installed an on your path. If that's the case, the easiest way would be to run the cyclone command against your topology using an npm script:

{
	"main": "index.js",
	"scripts": {
		"submit": "cyclone"
	}
}

In this case, the cyclone command will default to using the entrypoint file as identified in the "main" package.json property. Otherwise a topology can be specified using the -t/--topology flag. By default, this submits the topology to the Nimbus host configured in ~/.storm/storm.yaml.

# ~/.storm/storm.yaml
nimbus.host: "255.255.255.255"