title: How to debug VCL in varnish?
body: <p>How can I <code>print a log</code> in VCL?</p>
  
  <p>Can I print log info on screen?</p>
  
  <p>Can I do like this?</p>
  
  <pre><code>sub vcl_recv {
    ....
    log.info(req.http.host); // can i write a log here?
    ....
  }
  </code></pre>