rocky-consul

rocky middleware to easily setup a reverse HTTP proxy with service discovery and load balancer using Consul.

Essentially, this middleware will ask to Consul on every interval (configurable) to retrieve a list of URLs of a specific service (e.g: API, CDN, storage), and then them will be provided to rocky in order to balance the incoming HTTP traffic between those URLs.

Name	consul
Rocky	+0.2
Scope	global, route
Type	forward / balance

Installation

npm install rocky-consul --save

Usage

var rocky = require('rocky')
var consul = require('rocky-consul')
 
var proxy = rocky()

Plug in as global middleware

proxy.use(consul({
  // Servers refresh interval (default to 60000)
  interval: 60 * 5 * 1000,
  // App service name (required)
  service: 'web',
  // Use a custom datacenter (optional)
  datacenter: 'ams2',
  // Consul servers pool
  servers: [
    'http://demo.consul.io',
    'http://demo.consul.io'
  ]
}))
 
// Handle all the traffic
proxy.all('/*')
 
proxy.listen(3000)
console.log('Rocky server started')

Plug in as route level middleware

proxy
  .get('/download/:id')
  .use(consul({
    // Servers refresh interval (default to 60000)
    interval: 60 * 5 * 1000,
    // App service name (required)
    service: 'web',
    // Use a custom datacenter (optional)
    datacenter: 'ams2',
    // Consul servers pool
    servers: [
      'http://demo.consul.io',
      'http://demo.consul.io'
    ]
  }))
 
// Handle the rest of the traffic without using Consul
proxy.all('/*')
  .forward('http://my.server')
  .replay('http://old.server')
 
proxy.listen(3000)
console.log('Rocky server started')

API

consul(options) => Function(req, res, next)

Return a middleware function with the Consul client as static property function.consul.

Options

• service string - Consul service. Required
• servers array<string> - List of Consul servers URLs. Required
• datacenter string - Custom datacenter to use. If not defined the default one will be used
• tag string - Use a specific tag for the service
• defaultServers array<string> - Optional list of default target servers to balance. This avoid asking Consul the first time.
• protocol string - Transport URI protocol. Default to http
• timeout number - Consul server timeout in miliseconds. Default to 5000 = 5 seconds
• interval number - Consul servers update interval in miliseconds. Default to 120000 = 2 minutes
• headers object - Map of key-value headers to send to Consul
• auth string - Basic authentication for Consul. E.g: user:p@s$
• onRequest function - Executes this function before sending a request to Consul server. Passed arguments are: httpOpts
• onUpdate function - Executes this function on every servers update. Passed arguments are: err, servers
• onResponse function - Executes this function on every Consul server response. Passed arguments are: err, servers, res

Consul(options)

Internally used micro Consul client interface.

consul#servers(cb)

Returns the Consul servers for the given service. Passed arguments to the callback are: cb(err, servers).

consul#update(cb)

Perform the servers update asking to Consul Passed arguments to the callback are: cb(err, servers).

consul#startInterval()

Start the servers update interval as recurrent job for the given miliseconds defined at options.interval. You should not call this method unless you already called stopInterval().

consul#stopInterval()

Stop server update interval process.

License

MIT - Tomas Aparicio