json

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This is a JSON parsing filter. It takes an existing field which contains JSON and expands it into an actual data structure within the Logstash event.

By default it will place the parsed JSON in the root (top level) of the Logstash event, but this filter can be configured to place the JSON into any arbitrary event field, using the target configuration.

 

Synopsis

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This plugin supports the following configuration options:

Required configuration options:

json {
    source => ...
}

Available configuration options:

Setting Input type Required Default value

add_field

hash

No

{}

add_tag

array

No

[]

periodic_flush

boolean

No

false

remove_field

array

No

[]

remove_tag

array

No

[]

source

string

Yes

target

string

No

Details

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add_field

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  • Value type is hash
  • Default value is {}

If this filter is successful, add any arbitrary fields to this event. Field names can be dynamic and include parts of the event using the %{field}.

Example:

    filter {
      json {
        add_field => { "foo_%{somefield}" => "Hello world, from %{host}" }
      }
    }
[source,ruby]
    # You can also add multiple fields at once:
    filter {
      json {
        add_field => {
          "foo_%{somefield}" => "Hello world, from %{host}"
          "new_field" => "new_static_value"
        }
      }
    }

If the event has field "somefield" == "hello" this filter, on success, would add field foo_hello if it is present, with the value above and the %{host} piece replaced with that value from the event. The second example would also add a hardcoded field.

add_tag

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  • Value type is array
  • Default value is []

If this filter is successful, add arbitrary tags to the event. Tags can be dynamic and include parts of the event using the %{field} syntax.

Example:

    filter {
      json {
        add_tag => [ "foo_%{somefield}" ]
      }
    }
[source,ruby]
    # You can also add multiple tags at once:
    filter {
      json {
        add_tag => [ "foo_%{somefield}", "taggedy_tag"]
      }
    }

If the event has field "somefield" == "hello" this filter, on success, would add a tag foo_hello (and the second example would of course add a taggedy_tag tag).

periodic_flush

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  • Value type is boolean
  • Default value is false

Call the filter flush method at regular interval. Optional.

remove_field

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  • Value type is array
  • Default value is []

If this filter is successful, remove arbitrary fields from this event. Fields names can be dynamic and include parts of the event using the %{field} Example:

    filter {
      json {
        remove_field => [ "foo_%{somefield}" ]
      }
    }
[source,ruby]
    # You can also remove multiple fields at once:
    filter {
      json {
        remove_field => [ "foo_%{somefield}", "my_extraneous_field" ]
      }
    }

If the event has field "somefield" == "hello" this filter, on success, would remove the field with name foo_hello if it is present. The second example would remove an additional, non-dynamic field.

remove_tag

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  • Value type is array
  • Default value is []

If this filter is successful, remove arbitrary tags from the event. Tags can be dynamic and include parts of the event using the %{field} syntax.

Example:

    filter {
      json {
        remove_tag => [ "foo_%{somefield}" ]
      }
    }
[source,ruby]
    # You can also remove multiple tags at once:
    filter {
      json {
        remove_tag => [ "foo_%{somefield}", "sad_unwanted_tag"]
      }
    }

If the event has field "somefield" == "hello" this filter, on success, would remove the tag foo_hello if it is present. The second example would remove a sad, unwanted tag as well.

source

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  • This is a required setting.
  • Value type is string
  • There is no default value for this setting.

The configuration for the JSON filter:

    source => source_field

For example, if you have JSON data in the message field:

    filter {
      json {
        source => "message"
      }
    }

The above would parse the json from the message field

target

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  • Value type is string
  • There is no default value for this setting.

Define the target field for placing the parsed data. If this setting is omitted, the JSON data will be stored at the root (top level) of the event.

For example, if you want the data to be put in the doc field:

    filter {
      json {
        target => "doc"
      }
    }

JSON in the value of the source field will be expanded into a data structure in the target field.

if the target field already exists, it will be overwritten!