FreeSwitch controlled by Node.js middleware

useful-wind is a middleware framework for FreeSwitch. This module extends useful-wind with web and notification services to support call-handling. This module also provides a working FreeSwitch image as a Docker container under the name shimaore/thinkable-ducks.

Features

• Docker image with FreeSwitch and Node.js
• FreeSwitch calls are controlled by Node.js using the Event Socket
• Realtime notifications via extendable Socket.IO client

Processes

Three processes are managed by a common supervisord instance:

• the config application is ran once at startup to provide configuration, especially to create the FreeSwitch XML configuration file;
• the server application provides the Event Socket handler, web services, etc.
• FreeSwitch.

Supervisord can be controlled using its HTTP interface.

config

The config application will run any config middleware function.

It will then create a FreeSwitch XML configuration file by rendering the freeswitch template in the configuration object. The templace could be an acoustic-line template, or any function that will return a valid FreeSwitch XML configuration file.

Finally it will start the server application, and FreeSwitch itself.

Note: if the configuration contains a server_only flag, no FreeSwitch configuration is created, and FreeSwitch is not started.

server

The server application with first run any server_pre middleware function. This is used for example in the docker.tough-rate server module to initialize database access, etc.

The application will then start the Event Socket server (useful-wind), the web service, and the notify service.

Finally it will run any server_post middleware function.

web

The web service provides by default:

• GET /
• GET /supervisor

It may be extended by web middleware functions.

Middleware modules

Middleware modules are declared by setting cfg.use. They may contain the following fields:

• name: the middleware name (string)
• config: startup (function)
• init: call-processing initialization (function)
• include: call-processing middleware (function)
• web: web service (function)
• notify: notification service (function)

The functions are executed as indicated below, in the order they are declared in the cfg.use array. They are executed inside a Promise chain and may therefor return Promises.

config middlewares

A thinkable-ducks middleware module may contain config-time middleware functions which are ran inside the config application. The config application is a separate process and runs before the server application and FreeSwitch are started.

• config middleware in a context comprising of this.cfg.

The this.cfg object is shared amongst all these functions, but not with the modules in the server application (since that application is a separate process and is ran after the config application is completed).

server middlewares

A thinkable-ducks middleware module may contain server-time middleware functions which are ran inside the server application. The server application is a Node.js process which runs concurrently to FreeSwitch.

Some functions are executed by useful-wind:

• init is ran after the call-router is created but before call-routing starts taking place; this is a good place to extend the cfg object with any application-specific call-processing-related data.
• include is used to process FreeSwich calls.

Some functions are executed by this module (thinkable-ducks):

• web runs in the context of a zappajs application, extended with a this.cfg helper, and is used to provide web services.
• notify runs in a context comprising of this.cfg and this.socket (the Socket.IO client), and is used to notify and receive notifications from e.g. a spicy-action server.

The this.cfg object is shared amongst all these functions.

Deployment

An application is build out of middleware modules. The main application may look as follows.

index.coffee.md

cfg = require process.env.CONFIG

cfg.use = [
  require 'huge-play/middleware/setup'
  require 'huge-play/middleware/client/media'
  # etc. `require` any middleware module you might need
]

# A renderable `acoustic-line` templace to generate
# the FreeSwitch XML configuration.
cfg.freeswitch = require 'tough-rate/conf/freeswitch'

ducks = require 'thinkable-ducks'
ducks cfg

package.json

npm init

coffee-script is required by the supervisord.conf scripts.

npm install --save coffee-script

Install any middleware package you may require (including your own packages).

npm install --save thinkable-ducks huge-play tough-rate ...

Dockerfile

FROM shimaore/thinkable-ducks
COPY . /opt/thinkable-ducks
RUN npm install

Build using docker.io

docker build .