# Logstash parsing in JSON

**URL:** https://discuss.elastic.co/t/logstash-parsing-in-json/249659
**Category:** Logstash
**Created:** [September 23, 2020, 12:35pm UTC](https://discuss.elastic.co/t/logstash-parsing-in-json/249659 "2020-09-23T12:35:01Z")
**Posts on this page:** 1
**Showing post:** 7

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### Author: ![grumo35](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/grumo35/32/59451_2.png) [@grumo35](https://discuss.elastic.co/u/grumo35)
#### Post date: [September 23, 2020, 1:11pm UTC](https://discuss.elastic.co/t/logstash-parsing-in-json/249659/7 "2020-09-23T13:11:41Z")

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> [@Logstash::Event and Ruby code for dynamic tags with Logstash 2.3.4](https://discuss.elastic.co/t/logstash-event-and-ruby-code-for-dynamic-tags-with-logstash-2-3-4/71458):
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> Hi. I use Logstash 2.3.4 to read events from Kafka broker and have a problem with the filtering. I am trying to flatten the uniq\_log\_name1 object and turn uniq\_log\_name1 into a tag. My problem is not knowing what dynamic variable is available within the Ruby code interpreter after Kafka decodes the event as JSON. My testing works fine on the command-line but when using the Kafka input it fails because of the JSON decoding. I know this by testing with json codec on stdin and by disabling jso…

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