A first take on http://freelancing-gods.com/posts/script_nginx

nginx

#!/usr/bin/env ruby
require "optparse"
require "erb"

module Script
  class Nginx
    TEMP_PATH = "tmp/nginx.conf"

    def initialize
      @host = "0.0.0.0"
      @port = "8080"

      parse_nginx_options
      parse_rails_options
      load_temp_config unless @config
    end

    def run
      puts "=> Booting nginx"
      `nginx -p . -c #@config`
      puts "=> nginx proxying to Rails on http://#@host:#@port"
      at_exit do
        `nginx -p . -c #@config -s stop`
        File.delete @config if @config == TEMP_PATH
      end
      load "script/server"
    end

    private

    def parse_nginx_options
      ARGV.options do |opts|
        opts.banner = "Usage: #$0 [options] -- [script/server options]"

        opts.on("-P", "--nginx-port=port",
          "Runs nginx on the specified port.", "Default: #@port",
          String) { |port| @port = port }

        opts.on("-B", "--nginx-binding=ip",
          "Binds nginx to the specified ip.", "Default: #@host",
          String) { |host| @host = host }

        opts.on("-C", "--nginx-config=file",
          "Use custom nginx configuration file",
          String) { |config| @config = config }

        opts.on("-h", "--help",
          "Show this help message.") { puts opts; exit }

        begin
          opts.parse!
        rescue OptionParser::ParseError => e
          warn e
          puts opts
          exit 1
        end
      end
    end

    def parse_rails_options
      @app_host = @host
      @app_port = "3000"

      ARGV.clone.options do |opts|
        opts.on("-p", "--port=port")  { |port| @app_port = port }
        opts.on("-b", "--binding=ip") { |host| @app_host = host }
        opts.parse!
      end
    end

    def load_temp_config
      File.open TEMP_PATH, "w" do |file|
        file.write ERB.new(DATA.read).result(binding)
        @config = file.path
      end
    end
  end
end

Script::Nginx.new.run

__END__
pid tmp/pids/nginx.pid;
error_log log/nginx.error.log;

events {
  worker_connections 1024;
}

http {
  access_log log/nginx.access.log;
  error_log log/nginx.error.log;

  client_body_temp_path tmp/nginx.client_body_temp;
  fastcgi_temp_path tmp/nginx.fastcgi_temp;
  proxy_temp_path tmp/nginx.proxy_temp;

  gzip on;

  upstream proxy {
    server <%= @app_host %>:<%= @app_port %>;
  }

  server {
    listen <%= @port %>;
    server_name <%= @host %>;

    location / {
      root public;
      index index.html;

      if ($request_uri ~* "\.(ico|css|js|gif|jpe?g|png)\?[0-9]+$") {
        expires max;
        break;
      }

      if (-f $request_filename) {
        break;
      }

      if (!-f $request_filename) {
        proxy_pass http://proxy;
        break;
      }

      error_page 404 = /404.html;
      error_page 422 = /422.html;
      error_page 500 502 502 504 = /500.html;
    }
  }
}