# How to overwrite message (set to minus) if it is not overwrited in grok?

**URL:** <https://discuss.elastic.co/t/how-to-overwrite-message-set-to-minus-if-it-is-not-overwrited-in-grok/138518>\
**Category:** Logstash\
**Created:** [July 4, 2018, 9:11am UTC](https://discuss.elastic.co/t/how-to-overwrite-message-set-to-minus-if-it-is-not-overwrited-in-grok/138518 "2018-07-04T09:11:26Z")\
**Posts on this page:** 1\
**Showing post:** 8

<div class="post-metadata">

**Author:** ![Badger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/badger/32/25190_2.png) [@Badger](https://discuss.elastic.co/u/Badger)\
**Post date:** [July 4, 2018, 5:49pm UTC](https://discuss.elastic.co/t/how-to-overwrite-message-set-to-minus-if-it-is-not-overwrited-in-grok/138518/8 "2018-07-04T17:49:40Z")

</div>

You can remove the empty array using

```
ruby {
    code => '
        if event.get("tags") == []
            event.remove("tags")
        end
    ' 
}

```

And in the json filter, if you do not actually want the json parsed, parse into a sub-field of [@metadata]

```
json { source => "message" target => [@metadata][junk]" }
```

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_[View the full topic](https://discuss.elastic.co/t/how-to-overwrite-message-set-to-minus-if-it-is-not-overwrited-in-grok/138518)._