hipache reimplimented in lua in nginx

hipache.nginx.conf

location / {
    set $proxy_to "";

    access_by_lua "
        local redis = require 'redis'
        local red = redis:new()
        red:connect('127.0.0.1', 6379)

        local headers = ngx.req.get_headers()
        local hosts = red:smembers('frontend:' .. headers['host'])
        local chosen = hosts[math.random(#hosts)]
        ngx.var.proxy_to = chosen
    ";

    proxy_pass http://$proxy_to;
}