# Cann't use custom fields as a condition to drop fields

**URL:** <https://discuss.elastic.co/t/cannt-use-custom-fields-as-a-condition-to-drop-fields/94304>\
**Category:** Beats\
**Tags:** filebeat\
**Created:** [July 24, 2017, 10:18am UTC](https://discuss.elastic.co/t/cannt-use-custom-fields-as-a-condition-to-drop-fields/94304 "2017-07-24T10:18:33Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Yaohua](https://avatars.discourse-cdn.com/v4/letter/y/3be4f8/32.png) [@Yaohua](https://discuss.elastic.co/u/Yaohua)\
**Post date:** [July 24, 2017, 10:18am UTC](https://discuss.elastic.co/t/cannt-use-custom-fields-as-a-condition-to-drop-fields/94304/1 "2017-07-24T10:18:33Z")

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This is my config

```auto
filebeat.prospectors:
- input_type: log
  paths:
    - /var/log/xaa
  fields:
    Host: ${HOSTNAME}
  fields_under_root: true
  document_type: nginx
  tags: test
  exclude_lines: ['GET / HTTP/1.1"']
processors:
- drop_fields.when:
    - contains:
      - Host: 'vm1'
        - fields:
          - "beat"
          - "offset"

```

I use `filebeat -c /etc/filebeat/filebeat.yml -path.logs /var/log/filebeat/ -path.data /var/lib/filebeat/ -configtest`  
The filebeat output

> filebeat2017/07/24 10:12:14.974970 beat.go:339: CRIT Exiting: error loading config file: yaml: line 25: did not find expected key  
> Exiting: error loading config file: yaml: line 25: did not find expected key

---

<div class="post-metadata">

**Author:** ![tudor](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/tudor/32/3753_2.png) [@tudor](https://discuss.elastic.co/u/tudor)\
**Post date:** [July 24, 2017, 12:14pm UTC](https://discuss.elastic.co/t/cannt-use-custom-fields-as-a-condition-to-drop-fields/94304/2 "2017-07-24T12:14:39Z")

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Try this:

```auto
processors:
- drop_fields:
    fields: ["beat", "offset"]
    when.contains.host: "vm1"

```

I didn't test, but that's how I would write it.

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<div class="post-metadata">

**Author:** ![Yaohua](https://avatars.discourse-cdn.com/v4/letter/y/3be4f8/32.png) [@Yaohua](https://discuss.elastic.co/u/Yaohua)\
**Post date:** [July 25, 2017, 1:49am UTC](https://discuss.elastic.co/t/cannt-use-custom-fields-as-a-condition-to-drop-fields/94304/3 "2017-07-25T01:49:43Z")

</div>

it's work.thanks.

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<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 22, 2017, 1:50am UTC](https://discuss.elastic.co/t/cannt-use-custom-fields-as-a-condition-to-drop-fields/94304/4 "2017-08-22T01:50:20Z")

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