smoynes / ballast

A Plug-based HTTP load balancer and reverse proxy

Ballast

An HTTP reverse proxy and load balancer.

Usage

Install and build the application and dependencies:

$ git clone [e-mail]:normcode/ballast.git
$ cd ballast
$ mix deps.get
Running dependency resolution
...
$ mix compile
...

Create a configuration file, ./config/proxy.exs:

use Mix.Config
alias Ballast.Plug.Proxy

config :ballast, [
  proxy_port: 8080,
  routes: [
    [path:   "/httpbin", # matches path
     prefix: "/httpbin", # removes path prefix
     plug:   {Proxy, [origin: "httpbin.org"]}], # request is proxied to origin
    [host: "example.org", # matches host header, exactly
     plug:   {Proxy, [origin: "localhost:4000"]}]
  ]
]

Start the application within the configured environment:

$ MIX_ENV=proxy iex -S mix
$ curl localhost:8080/httpbin/get -i
HTTP/1.1 200 OK
cache-control: max-age=0, private, must-revalidate
access-control-allow-credentials: true
access-control-allow-origin: *
connection: keep-alive
content-length: 209
content-type: application/json
date: Mon, 31 Oct 2016 04:55:46 GMT
server: nginx
via: 1.1 ballast

{
  "args": {},
  "headers": {
    "Accept": "*/*",
    "Content-Length": "0",
    "Host": "httpbin.org",
    "User-Agent": "curl/7.43.0"
  },
  "origin": "10.0.0.1",
  "url": "http://httpbin.org/get"
}

The HTTP dispatch rules can be changed at runtime. From the iex REPL:

iex> Config.update(rules: [[host: "example.com", plug: {SomePlug, []}]])
:ok