# Kv plugin not parsing null value

**URL:** <https://discuss.elastic.co/t/kv-plugin-not-parsing-null-value/138751>\
**Category:** Logstash\
**Created:** [July 5, 2018, 2:34pm UTC](https://discuss.elastic.co/t/kv-plugin-not-parsing-null-value/138751 "2018-07-05T14:34:28Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![yodog](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/yodog/32/4822_2.png) [@yodog](https://discuss.elastic.co/u/yodog)\
**Post date:** [July 5, 2018, 2:34pm UTC](https://discuss.elastic.co/t/kv-plugin-not-parsing-null-value/138751/1 "2018-07-05T14:34:28Z")

</div>

using `kv` to parse iptables logs, i cant get it to save the `MAC` field

> [2928868.448110] [iptables] LOGDROP IN=eth0 OUT= MAC=00:50:56:9a:13:2a:02:1f:a0:00:0d:01:08:00 SRC=5.188.207.7 DST=8.8.8.8 LEN=60 TOS=0x08 PREC=0x20 TTL=50 ID=36130 DF PROTO=TCP SPT=31514 DPT=993 WINDOW=29200 RES=0x00 SYN URGP=0

the problem clearly is in the `OUT` field, which doesn't have a value, so i end up with

> "OUT": "MAC=00:50:56:9a:13:2a:02:1f:a0:00:0d:01:08:00",

if i explicitly declare the fields to be parsed with `include_keys` and `recursive`

```
kv {
    add_tag => ["iptables", "logdrop"]
    allow_duplicate_values => false
    include_keys => ["DPT", "DST", "MAC", "PROTO", "SPT", "SRC"]
    recursive => true
}

```

i don't get a `OUT` field at all (that's ok), but no `MAC` field as well (not ok)

expected result:

> "MAC": "00:50:56:9a:13:2a:02:1f:a0:00:0d:01:08:00",

any ideas?

also:

1- isn't the default behavior something like "get everything after `value_split` until `field_split` is found" ?

2- could we have a `ignore_empty` configuration option? something like

```
kv {
    ignore_empty => true
}

```

---

<div class="post-metadata">

**Author:** ![yodog](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/yodog/32/4822_2.png) [@yodog](https://discuss.elastic.co/u/yodog)\
**Post date:** [July 5, 2018, 3:24pm UTC](https://discuss.elastic.co/t/kv-plugin-not-parsing-null-value/138751/2 "2018-07-05T15:24:33Z")

</div>

forgot to say that `logstash-plain.log` is being flooded with the error generated by the empty `OUT=`

> [2018-07-05T12:20:26,297][WARN][logstash.outputs.elasticsearch] Could not index event to Elasticsearch. {:status=\>400, :action=\>["index", {:\_id=\>nil, :\_index=\>"iptables-2018.07.05", :\_type=\>"doc", :\_routing=\>nil}, #LogStash::Event:0x85585ea], :response=\>{"index"=\>{"\_index"=\>"iptables-2018.07.05", "\_type"=\>"doc", "\_id"=\>"gPsHa2QB7yvTzEaiu4if", "status"=\>400, "error"=\>{"type"=\>"mapper\_parsing\_exception", "reason"=\>"**failed to parse [OUT]**", "caused\_by"=\>{"type"=\>"illegal\_state\_exception", "reason"=\>"Can't get text on a START\_OBJECT at 1:72"}}}}}

and according to the [changelog](https://github.com/logstash-plugins/logstash-filter-kv/blob/v4.1.1/CHANGELOG.md) it should be correctly parsed by now?

> 4.1.1  
> bugfix: correctly handle empty values between value separator and field separator (#58)

---

<div class="post-metadata">

**Author:** ![yodog](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/yodog/32/4822_2.png) [@yodog](https://discuss.elastic.co/u/yodog)\
**Post date:** [July 5, 2018, 3:32pm UTC](https://discuss.elastic.co/t/kv-plugin-not-parsing-null-value/138751/3 "2018-07-05T15:32:27Z")

</div>

> <https://github.com/logstash-plugins/logstash-filter-kv/issues/65>

---

<div class="post-metadata">

**Author:** ![yodog](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/yodog/32/4822_2.png) [@yodog](https://discuss.elastic.co/u/yodog)\
**Post date:** [July 20, 2018, 5:11pm UTC](https://discuss.elastic.co/t/kv-plugin-not-parsing-null-value/138751/4 "2018-07-20T17:11:42Z")

</div>

> <https://github.com/logstash-plugins/logstash-filter-kv/pull/67>

---

<div class="post-metadata">

**Author:** ![yaauie](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/yaauie/32/23363_2.png) [@yaauie](https://discuss.elastic.co/u/yaauie)\
**Post date:** [July 21, 2018, 2:19am UTC](https://discuss.elastic.co/t/kv-plugin-not-parsing-null-value/138751/5 "2018-07-21T02:19:35Z")

</div>

Version 4.2.0 will likely ship early next week including this feature.

---

<div class="post-metadata">

**Author:** ![yaauie](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/yaauie/32/23363_2.png) [@yaauie](https://discuss.elastic.co/u/yaauie)\
**Post date:** [July 23, 2018, 11:23pm UTC](https://discuss.elastic.co/t/kv-plugin-not-parsing-null-value/138751/6 "2018-07-23T23:23:14Z")

</div>

Version 4.2.0 of the KV Filter Plugin has shipped, and will be included by default in the upcoming Logstash 6.4.0 next week.

You can also [update](https://www.elastic.co/guide/en/logstash/current/working-with-plugins.html#updating-plugins) the plugin within your existing Logstash installation:

```auto
${LOGSTASH_HOME}/bin/logstash-plugin update logstash-filter-kv

```

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [August 20, 2018, 11:23pm UTC](https://discuss.elastic.co/t/kv-plugin-not-parsing-null-value/138751/7 "2018-08-20T23:23:16Z")

</div>

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