A Seneca.js transport plugin

seneca-servicebus-transport

This plugin allows seneca listeners and clients to communicate over Oasis AMQP 1.0 using Azure Service Bus.

This project is based on Seneca AMQP Transport.

Install

npm install seneca-servicebus-transport

Usage

The following snippets showcase the most basic usage examples.

Listener

require('seneca')()
  .use('seneca-servicebus-transport')
  .add('role:create', function(message, done) {
    return done(null, {
      pid: process.pid,
      id: Math.floor(Math.random() * (message.max - message.min + 1)) + message.min
    });
  })
  .listen({
    type: 'servicebus',
    pin: 'role:create',
    connection_string: '****************'
  });

How it works

A listener creates a topic and and a subscription for each pattern.

In the example above, the following things are declared:

• A topic named role.create.
• A subscription to role.create

Client

var client = require('seneca')()
  .use('seneca-servicebus-transport')
  .client({
    type: 'servicebus',
    pin: 'role:create',
    connection_string: '****************'
  });

setInterval(function() {
  client.act('role:create', {
    max: 100,
    min: 50
  }, console.log);
}, 500);

How it works

A client creates an exclusive, randomly named response queue (something similar to seneca.res.x42jK0l) and starts consuming from it - much like a listener would do. On every act, the client publishes the message to the seneca.topic topic built from the pin that matches the act pattern. In the simple example above, the pattern is role:create which equals the only declared pin. With that, the routing key role.create is inferred. An AMQP replyTo header is set to the name of the random queue, in an [RPC-schema][7] fashion.

Manual queue naming on a client (using the name parameter as seen in the listener configuration) is not supported. Client queues are deleted once the client disconnect and re-created each time.

As you can see, pins play an important role on routing messages on the broker, so in order for a listener to receive messages from a client, their pins must match.

In the example, the following things are declared:

• An exclusive queue with a random alphanumeric name (like seneca.res.x42jK0l).

Clients do not declare the queue of their listener counterpart. So, if the message does not reach its destination and is discarded, the seneca instance will fail with a TIMEOUT error on the client side.

Options

The following object describes the available options for this transport. These are applicable to both clients and listeners.

{
  "servicebus": {
    "type": "topic",
    "topics": {},
    "queues": {
      "action": {
        "prefix": "seneca",
        "separator": ".",
        "options": {
          "durable": true
        }
      },
      "response": {
        "prefix": "seneca.res",
        "separator": ".",
        "options": {
          "autoDelete": true,
          "exclusive": true
        }
      }
    }
  }
}

Run the examples

There are simple examples under the /examples directory. To run them, just execute:

# Start listener.js
cd examples
SERVICEBUS_CONNECTION_STRING='Endpoint=sb://lorem.servicebus.windows.net/;SharedAccessKeyName=******;SharedAccessKey=***' node listener.js
2016-07-01T02:48:47.164Z wo1nwx8oq3xp/1467341327145/21846/- INFO  hello Seneca/2.1.0/wo1nwx8oq3xp/1467341327145/21846/- 
2016-07-01T02:48:47.957Z wo1nwx8oq3xp/1467341327145/21846/- INFO  listen  {type:servicebus,pin:role:create,connection_string:Endpoint=sb://------.servicebus.windows.net;SharedAcc

# Start client.js
cd examples
SERVICEBUS_CONNECTION_STRING='Endpoint=sb://lorem.servicebus.windows.net/;SharedAccessKeyName=******;SharedAccessKey=***' node listener.js
2016-07-01T02:50:40.230Z ul9sgk41i253/1467341440211/21948/- INFO  hello Seneca/2.1.0/ul9sgk41i253/1467341440211/21948/- 
2016-07-01T02:50:41.020Z ul9sgk41i253/1467341440211/21948/- INFO  client  {type:servicebus,pin:role:create,connection_string:Endpoint=sb://------.servicebus.windows.net;SharedAcc 
null { pid: 21846, id: 42 } { id: 'mgpk8ggtnh01/3oax9b5p695w',
  accept: 'wo1nwx8oq3xp/1467341327145/21846/-',
  track: [ 'ul9sgk41i253/1467341440211/21948/-' ],
  time: 
   { client_sent: 1467341443033,
     listen_recv: 1467341443174,
     listen_sent: 1467341443179,
     client_recv: 1467341443353 } }
null { pid: 21846, id: 83 } { id: 'cw258tsdm6t

Roadmap

• Add tests
• Enable queue based communication

Known issues

• Not possible to declare pins with wildcards

License

MIT

Any help/contribution is appreciated!