namespace :deploy do
  namespace :web do
    set(:maint_files) {["#{shared_path}/system/maintenance.html"]}

    desc <<-DESC
      Present a maintenance page to visitors. Disables your application's web \
      interface by writing a "maintenance.html" file to each web server. The \
      servers must be configured to detect the presence of this file, and if \
      it is present, always display it instead of performing the request.

      By default, the maintenance page will just say the site is down for \
      "maintenance", and will be back "shortly", but you can customize the \
      page by specifying the REASON environment variable:

        $ cap deploy:web:disable \\
              REASON="hardware upgrade"

      Further customization will require that you write your own task.
    DESC
    task :disable, :roles => :web, :except => { :no_release => true } do
      require 'erb'
      on_rollback { maint_files.each do |file|
                      run "if [ -e #{file} ]; then rm #{file}; fi"
                    end
                  }

      reason = ENV['REASON']

      template = File.read("public/maintenance.rhtml")
      result = ERB.new(template).result(binding)
      maint_files.each do |file|
        dir=File.dirname(file)
        tmpfile=%x{mktemp -u /tmp/capXXXXXXXX} # this seems like the quickest way to just get a name.
        tmpfile.chomp!
        put result, tmpfile, :mode => 0644
        run "if [ -d #{dir} -a \! -e #{file} ]; then mv #{tmpfile} #{file}; fi"
        run "chcon -t httpd_sys_content_t  #{file}; true" # we ignore this since some hosts have home on nfs
      end
    end

    desc <<-DESC
      Makes the application web-accessible again. Removes the \
      "maintenance.html" page generated by deploy:web:disable, which (if your \
      web servers are configured correctly) will make your application \
      web-accessible again.
    DESC
    task :enable, :roles => :web, :except => { :no_release => true } do
      maint_files.each do |file|
        run "if [ -e #{file} ]; then  rm #{file}; fi"
      end
    end
  end
end