storm-node

Simple implementation of the Storm-Multilang protocol for NodeJS apps. Handles reading, emitting, acking, failing, and handshaking.

At this time, Bolts and Spouts listen to process.stdin and write to process.stdout; they are meant to be run as standalone processes. To override this, change the input and output properties on your Bolt or Spout.

Version	Compatibility
>= 0.2.0	Storm 0.9.3+
<= 0.2.0	Storm <= 0.7.0

Example

Basic Bolt with automatic ack and anchoring

'use strict';
var util = require('util');
var Storm = require('storm-node');

var TestBolt = function() {
  // Put any init code here.
};
// Inherit BasicBolt for automatic ack & anchoring.
util.inherits(TestBolt, Storm.BasicBolt);

// BasicBolt's `process` method is fed an 'emit' function that
// *must* be used instead of `this.emit`. If you use `this.emit` directly,
// anchoring will not occur.
TestBolt.prototype.process = function(tuple, emit, done) {
  // Use provided `emit` function for automatic anchoring.
  emit(["val1","val2"]);
  // `done` must be called to ack.
  done();
};

var bolt = new TestBolt();
bolt.run();

Raw Bolt usage

'use strict';
var util = require('util');
var Storm = require('storm-node');

var SplitSentenceBolt = function() {
  // Put any init code here.
};
util.inherits(SplitSentenceBolt, Storm.Bolt);

// Optional. If present will be called with storm configuration.
SplitSentenceBolt.prototype.onConfig = function(stormConfig) {

};

// Optional. If present, will be called with topology context.
SplitSentenceBolt.prototype.onContext = function(topologyContext) {

};

SplitSentenceBolt.prototype.process = function(tuple) {
  // Configuration is also available via `this.stormConfig`
  var words = tuple.tuple[0].split(" ");

  for(var i = 0; i < words.length; i++)
  {
    // Pass the incoming `tuple` as the first argument to anchor this emit.
    this.emit(tuple, [words[i]]);
    // Or, without anchoring:
    // this.emit([words[i]]);
  }

  // In a subclass of Storm.Bolt, `ack` must be called manually.
  this.ack(tuple);
  // Or fail.
  // this.fail(tuple);
};

var ssb = new SplitSentenceBolt();

// `run()` will start listening for messages via stdin.
ssb.run();

Notes

storm-node exports four objects:

module.exports = {
  // Internal Communication library shared between Bolts and Spouts.
  // You usually don't need to use this.
  Storm: Storm,

  // A raw bolt. Similar to storm.Bolt in Java.
  // You need to manually ack when using this;
  // good for Bolts that emit more than once.
  Bolt: Bolt

  // Similar to storm.BasicBolt. Automatically
  // acks on callback.
  BasicBolt: BasicBolt,

  // WIP.
  Spout: Spout
}

TODO

• Implement Spouts

Author

Bryan Peterson - @lazyshot

Contributors

@strml @jandre