Fingerprint filter plugin v3.4.0

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  • Plugin version: v3.4.0
  • Released on: 2022-05-03
  • Changelog

For other versions, see the overview list.

To learn more about Logstash, see the Logstash Reference.

Getting help

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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.

Description

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Create consistent hashes (fingerprints) of one or more fields and store the result in a new field.

You can use this plugin to create consistent document ids when events are inserted into Elasticsearch. This approach means that existing documents can be updated instead of creating new documents.

When the method option is set to UUID the result won’t be a consistent hash but a random UUID. To generate UUIDs, prefer the uuid filter.

Event Metadata and the Elastic Common Schema (ECS)

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This plugin adds a hash value to event as an identifier. You can configure the target option to change the output field.

When ECS compatibility is disabled, the hash value is stored in the fingerprint field. When ECS is enabled, the value is stored in the [event][hash] field.

Here’s how ECS compatibility mode affects output.

ECS disabled ECS v1 Availability Description

fingerprint

[event][hash]

Always

a hash value of event

Fingerprint Filter Configuration Options

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

Setting Input type Required

base64encode

boolean

No

concatenate_sources

boolean

No

concatenate_all_fields

boolean

No

ecs_compatibility

string

No

key

string

No

method

string, one of ["SHA1", "SHA256", "SHA384", "SHA512", "MD5", "MURMUR3", "MURMUR3_128", IPV4_NETWORK", "UUID", "PUNCTUATION"]

Yes

source

array

No

target

string

No

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

 

base64encode

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  • Value type is boolean
  • Default value is false

When set to true, the SHA1, SHA256, SHA384, SHA512, MD5 and MURMUR3_128 fingerprint methods will produce base64 encoded rather than hex encoded strings.

concatenate_sources

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  • Value type is boolean
  • Default value is false

When set to true and method isn’t UUID or PUNCTUATION, the plugin concatenates the names and values of all fields given in the source option into one string (like the old checksum filter) before doing the fingerprint computation.

If false and multiple source fields are given, the target field will be single fingerprint of the last source field.

Example: concatenate_sources=false

This example produces a single fingerprint that is computed from "birthday," the last source field.

fingerprint {
  source => ["user_id", "siblings", "birthday"]
}

The output is:

"fingerprint" => "6b6390a4416131f82b6ffb509f6e779e5dd9630f".

Example: concatenate_sources=false with array

If the last source field is an array, you get an array of fingerprints.

In this example, "siblings" is an array ["big brother", "little sister", "little brother"].

fingerprint {
  source => ["user_id", "siblings"]
}

The output is:

 "fingerprint" => [
        [0] "8a8a9323677f4095fcf0c8c30b091a0133b00641",
        [1] "2ce11b313402e0e9884e094409f8d9fcf01337c2",
        [2] "adc0b90f9391a82098c7b99e66a816e9619ad0a7"
    ],

concatenate_all_fields

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  • Value type is boolean
  • Default value is false

When set to true and method isn’t UUID or PUNCTUATION, the plugin concatenates the names and values of all fields of the event into one string (like the old checksum filter) before doing the fingerprint computation. If false and at least one source field is given, the target field will be an array with fingerprints of the source fields given.

ecs_compatibility

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  • Value type is string
  • Supported values are:

    • disabled: unstructured data added at root level
    • v1: uses [event][hash] fields that are compatible with Elastic Common Schema

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

key

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

When used with the IPV4_NETWORK method fill in the subnet prefix length. With other methods, optionally fill in the HMAC key.

method

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  • This is a required setting.
  • Value can be any of: SHA1, SHA256, SHA384, SHA512, MD5, MURMUR3, MURMUR3_128, IPV4_NETWORK, UUID, PUNCTUATION
  • Default value is "SHA1"

The fingerprint method to use.

If set to SHA1, SHA256, SHA384, SHA512, or MD5 and a key is set, the corresponding cryptographic hash function and the keyed-hash (HMAC) digest function are used to generate the fingerprint.

If set to MURMUR3 or MURMUR3_128 the non-cryptographic MurmurHash function (either the 32-bit or 128-bit implementation, respectively) will be used.

If set to IPV4_NETWORK the input data needs to be a IPv4 address and the hash value will be the masked-out address using the number of bits specified in the key option. For example, with "1.2.3.4" as the input and key set to 16, the hash becomes "1.2.0.0".

If set to PUNCTUATION, all non-punctuation characters will be removed from the input string.

If set to UUID, a UUID will be generated. The result will be random and thus not a consistent hash.

source

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  • Value type is array
  • Default value is "message"

The name(s) of the source field(s) whose contents will be used to create the fingerprint. If an array is given, see the concatenate_sources option.

target

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  • Value type is string
  • Default value is "fingerprint" when ECS is disabled
  • Default value is "[event][hash]" when ECS is enabled

The name of the field where the generated fingerprint will be stored. Any current contents of that field will be overwritten.

Common options

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These configuration options are supported by all filter plugins:

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 {
      fingerprint {
        add_field => { "foo_%{somefield}" => "Hello world, from %{host}" }
      }
    }
    # You can also add multiple fields at once:
    filter {
      fingerprint {
        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 {
      fingerprint {
        add_tag => [ "foo_%{somefield}" ]
      }
    }
    # You can also add multiple tags at once:
    filter {
      fingerprint {
        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).

enable_metric

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  • 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 fingerprint filters. Adding a named ID in this case will help in monitoring Logstash when using the monitoring APIs.

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

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 {
      fingerprint {
        remove_field => [ "foo_%{somefield}" ]
      }
    }
    # You can also remove multiple fields at once:
    filter {
      fingerprint {
        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 {
      fingerprint {
        remove_tag => [ "foo_%{somefield}" ]
      }
    }
    # You can also remove multiple tags at once:
    filter {
      fingerprint {
        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.