# JSON filter (attempt to either prevent recursion or drop unwanted objects / nested fields)
**URL:** https://discuss.elastic.co/t/json-filter-attempt-to-either-prevent-recursion-or-drop-unwanted-objects-nested-fields/52903
**Category:** Logstash
**Created:** [June 15, 2016, 5:53pm UTC](https://discuss.elastic.co/t/json-filter-attempt-to-either-prevent-recursion-or-drop-unwanted-objects-nested-fields/52903 "2016-06-15T17:53:10Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@robinpblanchard](https://discuss.elastic.co/u/robinpblanchard)
#### Post date: [June 15, 2016, 5:53pm UTC](https://discuss.elastic.co/t/json-filter-attempt-to-either-prevent-recursion-or-drop-unwanted-objects-nested-fields/52903/1 "2016-06-15T17:53:10Z")
I have java/logback feeding a template a la:
```
{
"environment" : "somecrazyenvironment",
"appname" : "somecrazyapplication",
"logger" : "%logger",
"level" : "%level",
"thread" : "%thread",
"method" : "%class",
"message" : "%message"
}
```
which the JSON filter properly handles (and placed into a target json container field "app")
However, the "message" often contains yet more nested JSON. This causes consternation and often field-type conflicts ('tried to parse field [FIELD] as object, but found a concrete value').
Is it possible to prevent descending into nested JSON? (preferred)
Or
Is it possible to do some mutate/drop using some sort of logic based on for [app][NOTsome\_json\_subfield\_i\_care\_about] ? (seems ugly)
thanks!
---
### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [June 15, 2016, 6:06pm UTC](https://discuss.elastic.co/t/json-filter-attempt-to-either-prevent-recursion-or-drop-unwanted-objects-nested-fields/52903/2 "2016-06-15T18:06:45Z")
I'm not following. I'm pretty sure the json filter doesn't recurse into string fields and parse anything that looks like JSON. Could you give a minimal example that exhibits the problem?
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### Author:  [@robinpblanchard](https://discuss.elastic.co/u/robinpblanchard)
#### Post date: [June 15, 2016, 6:24pm UTC](https://discuss.elastic.co/t/json-filter-attempt-to-either-prevent-recursion-or-drop-unwanted-objects-nested-fields/52903/3 "2016-06-15T18:24:36Z")
Perhaps the problem lies elsewhere. I'll follow-up with my java developers. Despite their running application having a logback configured to send the above template, I am finding many more fields (aside those listed) being expanded....
---
### Author:  [@shaimr](https://discuss.elastic.co/u/shaimr)
#### Post date: [September 8, 2016, 8:05am UTC](https://discuss.elastic.co/t/json-filter-attempt-to-either-prevent-recursion-or-drop-unwanted-objects-nested-fields/52903/4 "2016-09-08T08:05:31Z")
I'm facing the same problem. How can I prevent JSON filter to parse the nested objects?
I opened a stackoverflow question:
[http://stackoverflow.com/questions/39371129/logstash-json-filter-for-only-one-level](http://stackoverflow.com/questions/39371129/logstash-json-filter-for-only-one-level)
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 4:39am UTC](https://discuss.elastic.co/t/json-filter-attempt-to-either-prevent-recursion-or-drop-unwanted-objects-nested-fields/52903/5 "2017-07-06T04:39:20Z")