title: Using Grok parser in Fluentd
body: <p>I am looking for a way to parse data using the grok parser, but i seem to be stuck on how to use it.
  My purpose is that i would like to add additional fields using a grok patter using a filter.</p>
  
  <p>Something like:</p>
  
  <pre><code>&lt;filter acme.**&gt;
      @type parser
      key_name log
      format grok
      &lt;parse&gt;
          &lt;grok&gt;
              @type grok
              grok_pattern grok_pattern %{TIMESTAMP_ISO8601:time_stamp}%{SPACE}
          &lt;/grok&gt;
      &lt;/parse&gt;
  &lt;/filter&gt;
  </code></pre>
  
  <p>Using this Fluend complains or warns that a lot of stuff is not used..</p>
  
  <ul>
  <li>parameter '@type' in  ....is not used.</li>
  <li>parameter 'grok_pattern' in  .. in  section  is not used</li>
  </ul>
  
  <p>Anu cue on how to use the Grok parser in Fluentd using a filter?</p>