Virgo.js

Virgo.js is a library for creating Virgo agents and agent endpoints in node.js.

var virgo = require('virgo.js');

Development Setup Instructions

Clone Virgo.js to obtain a local copy (you could also use the ssh url here).

$ git clone https://github.com/virgo-agent-toolkit/virgo.js.git virgo-js

Navigate to your new directory and install dependencies.

$ cd virgo-js
$ npm install

Now, build virgo.js with make.

$ make

Run the Example

Next, run the heartbeats example, described in the following section.

$ sudo node examples/heartbeats-only.js

In the output, you should expect a stream of heartbeat objects.

{
  "v": "0.1.0",
  "id": 42,
  "target": "heartbeats",
  "source": "Heartbeats",
  "method": "heartbeat.post",
  "params": {
    "timestamp": 1408568615206
  }
}

Heartbeats Example in Detail

The Heartbeats Only example demonstrates how virgo.js is used. The purpose of this example is for the agent to send heartbeats to demonstrate that it is still there (in the form of updates at a set interval).

var virgo = require('..');

// Create agent, endpoint, and a heartbeats feature.
var agent = virgo.agent;
var endpoint = virgo.endpoint;
var heartbeats = virgo.heartbeats;

// Use an unprivileged port to avoid having to run the example with sudo.
// If not provided, port will default to 443.
var portOption = {"port": 8443};

// Create an endpoint with an array of features:
// endpoint([feature 1, feature 2, feature 3...]).run();
//
// Here, a heartbeats feature is called with a callback as an argument. This means
// the heartbeats is in receive mode. When a heartbeat is received, the endpoint will
// run this callback.
endpoint([heartbeats(function(hb) {
  process.stdout.write('received hb\n');
  process.stdout.write(JSON.stringify(hb, 0, 2) + '\n');
})], portOption).run();

// Pass the agent a list of features (again, just one here). We call the heartbeats without a callback, which means the
// heartbeats will be in send mode. In send mode, heartbeats will set up a timer, and a heartbeat will be set at a 
// regular interval.
agent([heartbeats()], portOption).run();

Features in Virgo.js

Features work on streams between agents and endpoints. You can run a Hello, World example:

node examples/hello-world-demo.js

Expected output:

{"version":"1.0","host":"C02LV0QBFH04","timestamp":1409178850.34,"short_message":"server bound","full_message":null,"level":6,"facility":"virgojs.endpoint"}
{"version":"1.0","host":"C02LV0QBFH04","timestamp":1409178850.347,"short_message":"CONNECTED -> READY","full_message":null,"level":7,"facility":"virgojs.connection"}
{"version":"1.0","host":"C02LV0QBFH04","timestamp":1409178850.352,"short_message":"RESOLVED -> CONNECTED","full_message":null,"level":7,"facility":"virgojs.connection"}
{"version":"1.0","host":"C02LV0QBFH04","timestamp":1409178850.352,"short_message":"CONNECTED -> READY","full_message":null,"level":7,"facility":"virgojs.connection"}
{"version":"1.0","host":"C02LV0QBFH04","timestamp":1409178850.353,"short_message":"READY -> AUTHENTICATED","full_message":null,"level":7,"facility":"virgojs.connection"}
{"version":"1.0","host":"C02LV0QBFH04","timestamp":1409178850.354,"short_message":"READY -> AUTHENTICATED","full_message":null,"level":7,"facility":"virgojs.connection"}
Hello, world!

Using the example code as a base, you can write your own feature and register it with a virgo.js agent and/or endpoint. The following functions are required:

• feature.meta - Retrieves metadata about this feature
• feature.init - Defines how feature handles incoming streams
• feature.shutdown - Shuts down connections within the feature

License

Virgo.js is distributed under the Apache License 2.0.