title: Concatenate a word to an email using pre-defined grok filter
body: <p>first of all thank you for reading my question.
  i have an email address in a log in following format,</p>
  
  <pre><code>Apr 24 19:38:51 ip-10-0-1-204 sendmail[9489]: w3OJco1s009487: sendid:name@test.co.uk, delay=00:00:01, xdelay=00:00:01, mailer=smtp, pri=120318, relay=webmx.bglen.net. [10.0.3.231], dsn=2.0.0, stat=Sent (Ok: queued as E2DEF60724), w3OJco1s009487: to=&lt;username@domain.us&gt;, delay=00:00:01, xdelay=00:00:01, mailer=smtp, pri=120318, relay=webmx.[redacted].net. [10.0.3.231], dsn=2.0.0, stat=Sent (Ok: queued as E2DEF60724)
  </code></pre>
  
  <p>and i need to extract the email along with the word sendid</p>
  
  <p>output should look like this,</p>
  
  <pre><code>{
    "DATA": [
      [
        "sendid:name@test.co.uk"
      ]
    ]
  }
  </code></pre>
  
  <p>i have tried following but it only extracts email i tested it here, <a href="http://grokdebug.herokuapp.com/" rel="nofollow noreferrer">http://grokdebug.herokuapp.com/</a> ,</p>
  
  <pre><code>sendid:%{DATA},
  </code></pre>
  
  <p>How can i concatenate the word sendid: to the email without creating a new field or defining a new regex? can someone please help?</p>
  
  <p>i have also tried this but it doesn't work,</p>
  
  <pre><code>sendid:%{"sendid:"} %{DATA},
  </code></pre>