title: Grok pattern for Logstash input log file
body: <blockquote>
  <p>[1603870834] SERVICE ALERT: localhost;Swap Usage;OK;SOFT;2;SWAP OK - 1% free (0 MB out of 1023 MB)</p>
  </blockquote>
  <p>I have to filter that string example in <em>JSON</em> format for <em>Logstash</em> it is my <em>Nagios</em> log file output that I have to load into my ELK using <em>Logstash</em>, how I can write to grok for that?</p>