JSON filter plugin

• Plugin version: v3.2.1
• Released on: 2023-12-18
• Changelog

For other versions, see the Versioned plugin docs.

For questions about the plugin, open a topic in the Discuss forums. For bugs or feature requests, open an issue in Github. For the list of Elastic supported plugins, please consult the Elastic Support Matrix.

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.

This plugin has a few fallback scenarios when something bad happens during the parsing of the event. If the JSON parsing fails on the data, the event will be untouched and it will be tagged with _jsonparsefailure; you can then use conditionals to clean the data. You can configure this tag with the tag_on_failure option.

If the parsed data contains a @timestamp field, the plugin will try to use it for the events @timestamp, and if the parsing fails, the field will be renamed to _@timestamp and the event will be tagged with a _timestampparsefailure.

The plugin behaves the same regardless of ECS compatibility, except giving a warning when ECS is enabled and target isn’t set.

This plugin supports the following configuration options plus the Common options described later.

Also see Common options for a list of options supported by all filter plugins.

• Value type is string

• Supported values are:

  • disabled: does not use ECS-compatible field names
  • v1: Elastic Common Schema compliant behavior (warns when target isn’t set)

Controls this plugin’s compatibility with the Elastic Common Schema (ECS). See Event Metadata and the Elastic Common Schema (ECS) for detailed information.

• Value type is boolean
• Default value is false

Allows for skipping the filter on invalid JSON (this allows you to handle JSON and non-JSON data without warnings)

• 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.

• Value type is array
• Default value is ["_jsonparsefailure"]

Append values to the tags field when there has been no successful match

• 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.

These configuration options are supported by all filter plugins:

• 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}" }
  }
}

# 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.

• 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}" ]
  }
}

# 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).

• Value type is boolean
• Default value is true

Disable or enable metric logging for this specific plugin instance. By default we record all the metrics we can, but you can disable metrics collection for a specific plugin.

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

Add a unique ID to the plugin configuration. If no ID is specified, Logstash will generate one. It is strongly recommended to set this ID in your configuration. This is particularly useful when you have two or more plugins of the same type, for example, if you have 2 json filters. Adding a named ID in this case will help in monitoring Logstash when using the monitoring APIs.

filter {
  json {
    id => "ABC"
  }
}

• Value type is boolean
• Default value is false

Call the filter flush method at regular interval. Optional.

• 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}" ]
  }
}

# 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.

• 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}" ]
  }
}

# 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.