title: using logstash to parse csv file
body: <p>I have an elasticsearch index which I am using to index a set of documents.</p>
  
  <p>These documents are originally in csv format and I am looking parse these using logstash as this has powerful regular expression tools such as grok. </p>
  
  <p>My problem is that I have something along the following lines</p>
  
  <pre><code>field1,field2,field3,number@number#number@number#number@number
  </code></pre>
  
  <p>In the last column I have key value pairs key@value separated by # and there can be any number of these</p>
  
  <p>Is there a way for me to use logstash to parse this and get it to store the last column as the following json in elasticsearch (or some other searchable format) so I am able to search it</p>
  
  <pre><code>[
    {"key" : number, "value" : number},
    {"key" : number, "value" : number},
    ...
  ]
  </code></pre>