https://github.com/msgflo/msgflo-nodejs

Node.js participant support for MsgFlo
https://github.com/msgflo/msgflo-nodejs

amqp message-passing mqtt

Last synced: about 1 month ago
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Node.js participant support for MsgFlo

• Host: GitHub
• URL: https://github.com/msgflo/msgflo-nodejs
• Owner: msgflo
• License: mit
• Created: 2015-06-04T05:35:03.000Z (over 9 years ago)
• Default Branch: master
• Last Pushed: 2020-05-24T16:37:37.000Z (over 4 years ago)
• Last Synced: 2023-02-27T22:05:49.967Z (almost 2 years ago)
• Topics: amqp, message-passing, mqtt
• Language: CoffeeScript
• Size: 405 KB
• Stars: 9
• Watchers: 6
• Forks: 2
• Open Issues: 30
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGES.md
  • License: LICENSE

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README

        
# msgflo-nodejs [![Build Status](https://travis-ci.org/msgflo/msgflo-nodejs.svg?branch=master)](https://travis-ci.org/msgflo/msgflo-nodejs)

[MsgFlo](https://github.com/msgflo/msgflo) is a distributed, polyglot FBP (flow-based-programming)

runtime. It integrates with other FBP tools like the [Flowhub](http://flowhub.io) visual programming IDE.

This library makes it easy to create MsgFlo participants in JavaScript/CoffeScript on node.js.

## Status

**Production**

* Used at [TheGrid](https://thegrid.io) for all workers using AMQP/RabbitMQ,

including in [imgflo-server](https://github.com/jonnor/imgflo-server)

* Also used by [noflo-runtime-msgflo](https://github.com/noflo/noflo-runtime-msgflo)

* Experimental support for MQTT and direct transports

## Licence

MIT, see [./LICENSE](./LICENSE)

## Usage

Add as an NPM dependency

    npm install --save msgflo-nodejs

A simple participant (CoffeeScript)

    msgflo = require 'msgflo-nodejs'

    RepeatParticipant = (client, role) ->

      definition =

        component: 'Repeat'

        icon: 'file-word-o'

        label: 'Repeats in data without changes'

        inports: [

          id: 'in'

          type: 'any'

        ]

        outports: [

          id: 'out'

          type: 'any'

        ]

      process = (inport, indata, callback) ->

        return callback 'out', null, indata

      return new msgflo.participant.Participant client, definition, process, role

    client = msgflo.transport.getClient 'amqp://localhost'

    worker = RepeatParticipant client, 'repeater'

    worker.start (err) ->

      throw err if err

      console.log 'Worker started'

If you expose the participant factory function ([examples/Repeat.coffee](./examples/Repeat.coffee))

    module.exports = RepeatParticipant

Then you can use the `msgflo-nodejs` exectutable to start participant

    msgflo-nodejs --name repeater ./examples/Repeat.coffee

## Debugging

msgflo-nodejs uses the [debug NPM module](https://www.npmjs.com/package/debug).

You can enable (all) logging using:

    export DEBUG=msgflo*

## Supporting other transports

msgflo-nodejs has a transport abstraction layer. So to support a new messaging system,

implement `Client` and `MessageBroker` [interfaces](./src/interfaces.coffee).

You can then pass the Client instance into a `Participant`.

Or you can register a new transport using `msgflo.transport.register('mytransport', myTransportModule)`.

Then you can get a Client instance using `msgflo.transport.getClient('mytransport://somehost:666')`.

This has the advantage of also working when specifying the broker URL using

`msgflo-nodejs --broker` or `MSGFLO_BROKER=` environment variable.