title: How make a filter "does not contain" in Google Stackdriver logs
body: <p>In Google Stackdriver advanced filter I can insert something like:</p>
  
  <pre><code>resource.type="container"
  resource.labels.cluster_name="mycluster"
  textPayload!="Metric stackdriver_sink_successfully_sent_entry_count was not found in the cache."
  severity="INFO"
  textPayload:(helloworld)
  </code></pre>
  
  <p>The last rule means that the field <em>textPayload</em> should contain the string <em>helloworld</em>. 
  But I'm not able to find a way to add a NOT operator.</p>
  
  <p>I would use something like:</p>
  
  <pre><code>textPayload:!(helloworld)
  </code></pre>
  
  <p>but doesn't work</p>