Here is the template:

    <%= @log_path -%> {
      <%= @rotate_every %>
      rotate <%= @rotate_count %>
      compress
      <% if @delaycompress == true %>delaycompress
      <% end -%>missingok
      notifempty
      create <%= @create_mode -%> <%= @create_owner -%> <%= @create_group %>
      <% if @postrotate == true -%>postrotate
        <% @postrotate_cmd.each do |value| -%><%= value %>
      <% end -%>endscript<% end -%>
    }



When @postrotate is false the output looks like this. The `}` isn't to the left.

    /var/log/auth.log {
      weekly
      rotate 4
      compress
      delaycompress
      missingok
      notifempty
      create 0644 root adm
      }

When @postrotate is true the output looks like this. The second `invoke commnad` should be a bit to the right and `}`  should be on the new line to the left.

    /var/log/auth.log {
      weekly
      rotate 4
      compress
      delaycompress
      missingok
      notifempty
      create 0644 root adm
      postrotate
        invoke-rc.d rsyslog reload > /dev/null
      invoke-rc.d rsyslog reload > /dev/null
      endscript}

Expected output when @postrotate is false:


    /var/log/auth.log {
      weekly
      rotate 4
      compress
      delaycompress
      missingok
      notifempty
      create 0644 root adm
    }

Expected output when @postrotate is true:


    /var/log/auth.log {
      weekly
      rotate 4
      compress
      delaycompress
      missingok
      notifempty
      create 0644 root adm
      postrotate
        invoke-rc.d rsyslog reload > /dev/null
        invoke-rc.d rsyslog reload > /dev/null
      endscript
    }