:plugin: kv
:type: filter

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:version: %VERSION%
:release_date: %RELEASE_DATE%
:changelog_url: %CHANGELOG_URL%
:include_path: ../../../../logstash/docs/include
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[id="plugins-{type}s-{plugin}"]

=== Kv filter plugin

include::{include_path}/plugin_header.asciidoc[]

==== Description

This filter helps automatically parse messages (or specific event fields)
which are of the `foo=bar` variety.

For example, if you have a log message which contains `ip=1.2.3.4
error=REFUSED`, you can parse those automatically by configuring:
[source,ruby]
    filter {
      kv { }
    }

The above will result in a message of `ip=1.2.3.4 error=REFUSED` having
the fields:

* `ip: 1.2.3.4`
* `error: REFUSED`

This is great for postfix, iptables, and other types of logs that
tend towards `key=value` syntax.

You can configure any arbitrary strings to split your data on,
in case your data is not structured using `=` signs and whitespace.
For example, this filter can also be used to parse query parameters like
`foo=bar&baz=fizz` by setting the `field_split` parameter to `&`.

[id="plugins-{type}s-{plugin}-options"]
==== Kv Filter Configuration Options

This plugin supports the following configuration options plus the <<plugins-{type}s-{plugin}-common-options>> described later.

[cols="<,<,<",options="header",]
|=======================================================================
|Setting |Input type|Required
| <<plugins-{type}s-{plugin}-allow_duplicate_values>> |<<boolean,boolean>>|No
| <<plugins-{type}s-{plugin}-default_keys>> |<<hash,hash>>|No
| <<plugins-{type}s-{plugin}-exclude_keys>> |<<array,array>>|No
| <<plugins-{type}s-{plugin}-field_split>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-field_split_pattern>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-include_brackets>> |<<boolean,boolean>>|No
| <<plugins-{type}s-{plugin}-include_keys>> |<<array,array>>|No
| <<plugins-{type}s-{plugin}-prefix>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-recursive>> |<<boolean,boolean>>|No
| <<plugins-{type}s-{plugin}-remove_char_key>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-remove_char_value>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-source>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-target>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-tag_on_failure>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-tag_on_timeout>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-timeout_millis>> |<<number,number>>|No
| <<plugins-{type}s-{plugin}-transform_key>> |<<string,string>>, one of `["lowercase", "uppercase", "capitalize"]`|No
| <<plugins-{type}s-{plugin}-transform_value>> |<<string,string>>, one of `["lowercase", "uppercase", "capitalize"]`|No
| <<plugins-{type}s-{plugin}-trim_key>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-trim_value>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-value_split>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-value_split_pattern>> |<<string,string>>|No
| <<plugins-{type}s-{plugin}-whitespace>> |<<string,string>>, one of `["strict", "lenient"]`|No
|=======================================================================

Also see <<plugins-{type}s-{plugin}-common-options>> for a list of options supported by all
filter plugins.

&nbsp;

[id="plugins-{type}s-{plugin}-allow_duplicate_values"]
===== `allow_duplicate_values` 

  * Value type is <<boolean,boolean>>
  * Default value is `true`

A bool option for removing duplicate key/value pairs. When set to false, only
one unique key/value pair will be preserved.

For example, consider a source like `from=me from=me`. `[from]` will map to
an Array with two elements: `["me", "me"]`. To only keep unique key/value pairs,
you could use this configuration:
[source,ruby]
    filter {
      kv {
        allow_duplicate_values => false
      }
    }

[id="plugins-{type}s-{plugin}-default_keys"]
===== `default_keys` 

  * Value type is <<hash,hash>>
  * Default value is `{}`

A hash specifying the default keys and their values which should be added to the event
in case these keys do not exist in the source field being parsed.
[source,ruby]
    filter {
      kv {
        default_keys => [ "from", "logstash@example.com",
                         "to", "default@dev.null" ]
      }
    }

[id="plugins-{type}s-{plugin}-exclude_keys"]
===== `exclude_keys` 

  * Value type is <<array,array>>
  * Default value is `[]`

An array specifying the parsed keys which should not be added to the event.
By default no keys will be excluded.

For example, consider a source like `Hey, from=<abc>, to=def foo=bar`.
To exclude `from` and `to`, but retain the `foo` key, you could use this configuration:
[source,ruby]
    filter {
      kv {
        exclude_keys => [ "from", "to" ]
      }
    }

[id="plugins-{type}s-{plugin}-field_split"]
===== `field_split` 

  * Value type is <<string,string>>
  * Default value is `" "`

A string of characters to use as single-character field delimiters for parsing out key-value pairs.

These characters form a regex character class and thus you must escape special regex
characters like `[` or `]` using `\`.

*Example with URL Query Strings*

For example, to split out the args from a url query string such as
`?pin=12345~0&d=123&e=foo@bar.com&oq=bobo&ss=12345`:
[source,ruby]
    filter {
      kv {
        field_split => "&?"
      }
    }

The above splits on both `&` and `?` characters, giving you the following
fields:

* `pin: 12345~0`
* `d: 123`
* `e: foo@bar.com`
* `oq: bobo`
* `ss: 12345`

[id="plugins-{type}s-{plugin}-field_split_pattern"]
===== `field_split_pattern`

  * Value type is <<string,string>>
  * There is no default value for this setting.

A regex expression to use as field delimiter for parsing out key-value pairs.
Useful to define multi-character field delimiters.
Setting the `field_split_pattern` options will take precedence over the `field_split` option.

Note that you should avoid using captured groups in your regex and you should be
cautious with lookaheads or lookbehinds and positional anchors.

For example, to split fields on a repetition of one or more colons
`k1=v1:k2=v2::k3=v3:::k4=v4`:
[source,ruby]
    filter { kv { field_split_pattern => ":+" } }

To split fields on a regex character that need escaping like the plus sign
`k1=v1++k2=v2++k3=v3++k4=v4`:
[source,ruby]
    filter { kv { field_split_pattern => "\\+\\+" } }

[id="plugins-{type}s-{plugin}-include_brackets"]
===== `include_brackets` 

  * Value type is <<boolean,boolean>>
  * Default value is `true`

A boolean specifying whether to treat square brackets, angle brackets,
and parentheses as value "wrappers" that should be removed from the value.
[source,ruby]
    filter {
      kv {
        include_brackets => true
      }
    }

For example, the result of this line:
`bracketsone=(hello world) bracketstwo=[hello world] bracketsthree=<hello world>`

will be:

* bracketsone: hello world
* bracketstwo: hello world
* bracketsthree: hello world

instead of:

* bracketsone: (hello
* bracketstwo: [hello
* bracketsthree: <hello


[id="plugins-{type}s-{plugin}-include_keys"]
===== `include_keys` 

  * Value type is <<array,array>>
  * Default value is `[]`

An array specifying the parsed keys which should be added to the event.
By default all keys will be added.

For example, consider a source like `Hey, from=<abc>, to=def foo=bar`.
To include `from` and `to`, but exclude the `foo` key, you could use this configuration:
[source,ruby]
    filter {
      kv {
        include_keys => [ "from", "to" ]
      }
    }

[id="plugins-{type}s-{plugin}-prefix"]
===== `prefix` 

  * Value type is <<string,string>>
  * Default value is `""`

A string to prepend to all of the extracted keys.

For example, to prepend arg_ to all keys:
[source,ruby]
    filter { kv { prefix => "arg_" } }

[id="plugins-{type}s-{plugin}-recursive"]
===== `recursive` 

  * Value type is <<boolean,boolean>>
  * Default value is `false`

A boolean specifying whether to drill down into values
and recursively get more key-value pairs from it.
The extra key-value pairs will be stored as subkeys of the root key.

Default is not to recursive values.
[source,ruby]
    filter {
      kv {
        recursive => "true"
      }
    }


[id="plugins-{type}s-{plugin}-remove_char_key"]
===== `remove_char_key` 

  * Value type is <<string,string>>
  * There is no default value for this setting.

A string of characters to remove from the key.

These characters form a regex character class and thus you must escape special regex
characters like `[` or `]` using `\`.

Contrary to trim option, all characters are removed from the key, whatever their position.

For example, to remove `<` `>` `[` `]` and `,` characters from keys:
[source,ruby]
    filter {
      kv {
        remove_char_key => "<>\[\],"
      }
    }

[id="plugins-{type}s-{plugin}-remove_char_value"]
===== `remove_char_value` 

  * Value type is <<string,string>>
  * There is no default value for this setting.

A string of characters to remove from the value.

These characters form a regex character class and thus you must escape special regex
characters like `[` or `]` using `\`.

Contrary to trim option, all characters are removed from the value, whatever their position.

For example, to remove `<`, `>`, `[`, `]` and `,` characters from values:
[source,ruby]
    filter {
      kv {
        remove_char_value => "<>\[\],"
      }
    }

[id="plugins-{type}s-{plugin}-source"]
===== `source` 

  * Value type is <<string,string>>
  * Default value is `"message"`

The field to perform `key=value` searching on

For example, to process the `not_the_message` field:
[source,ruby]
    filter { kv { source => "not_the_message" } }

[id="plugins-{type}s-{plugin}-target"]
===== `target` 

  * Value type is <<string,string>>
  * There is no default value for this setting.

The name of the container to put all of the key-value pairs into.

If this setting is omitted, fields will be written to the root of the
event, as individual fields.

For example, to place all keys into the event field kv:
[source,ruby]
    filter { kv { target => "kv" } }

[id="plugins-{type}s-{plugin}-tag_on_failure"]
===== `tag_on_failure`

  * Value type is <<string,string>>
  * The default value for this setting is `_kv_filter_error`.

When a kv operation causes a runtime exception to be thrown within the plugin,
the operation is safely aborted without crashing the plugin, and the event is
tagged with the provided value.

[id="plugins-{type}s-{plugin}-tag_on_timeout"]
===== `tag_on_timeout`

  * Value type is <<string,string>>
  * The default value for this setting is `_kv_filter_timeout`.

When timeouts are enabled and a kv operation is aborted, the event is tagged
with the provided value (see: <<plugins-{type}s-{plugin}-timeout_millis>>).

[id="plugins-{type}s-{plugin}-timeout_millis"]
===== `timeout_millis`

  * Value type is <<number,number>>
  * The default value for this setting is 30000 (30 seconds).
  * Set to zero (`0`) to disable timeouts

Timeouts provide a safeguard against inputs that are pathological against the
regular expressions that are used to extract key/value pairs. When parsing an
event exceeds this threshold the operation is aborted and the event is tagged
in order to prevent the operation from blocking the pipeline
(see: <<plugins-{type}s-{plugin}-tag_on_timeout>>).

[id="plugins-{type}s-{plugin}-transform_key"]
===== `transform_key` 

  * Value can be any of: `lowercase`, `uppercase`, `capitalize`
  * There is no default value for this setting.

Transform keys to lower case, upper case or capitals.

For example, to lowercase all keys:
[source,ruby]
    filter {
      kv {
        transform_key => "lowercase"
      }
    }

[id="plugins-{type}s-{plugin}-transform_value"]
===== `transform_value` 

  * Value can be any of: `lowercase`, `uppercase`, `capitalize`
  * There is no default value for this setting.

Transform values to lower case, upper case or capitals.

For example, to capitalize all values:
[source,ruby]
    filter {
      kv {
        transform_value => "capitalize"
      }
    }

[id="plugins-{type}s-{plugin}-trim_key"]
===== `trim_key` 

  * Value type is <<string,string>>
  * There is no default value for this setting.

A string of characters to trim from the key. This is useful if your
keys are wrapped in brackets or start with space.

These characters form a regex character class and thus you must escape special regex
characters like `[` or `]` using `\`.

Only leading and trailing characters are trimed from the key.

For example, to trim `<` `>` `[` `]` and `,` characters from keys:
[source,ruby]
    filter {
      kv {
        trim_key => "<>\[\],"
      }
    }

[id="plugins-{type}s-{plugin}-trim_value"]
===== `trim_value` 

  * Value type is <<string,string>>
  * There is no default value for this setting.

Constants used for transform check
A string of characters to trim from the value. This is useful if your
values are wrapped in brackets or are terminated with commas (like postfix
logs).

These characters form a regex character class and thus you must escape special regex
characters like `[` or `]` using `\`.

Only leading and trailing characters are trimed from the value.

For example, to trim `<`, `>`, `[`, `]` and `,` characters from values:
[source,ruby]
    filter {
      kv {
        trim_value => "<>\[\],"
      }
    }

[id="plugins-{type}s-{plugin}-value_split"]
===== `value_split` 

  * Value type is <<string,string>>
  * Default value is `"="`

A non-empty string of characters to use as single-character value delimiters for parsing out key-value pairs.

These characters form a regex character class and thus you must escape special regex
characters like `[` or `]` using `\`.

For example, to identify key-values such as
`key1:value1 key2:value2`:
[source,ruby]
    filter { kv { value_split => ":" } }


[id="plugins-{type}s-{plugin}-value_split_pattern"]
===== `value_split_pattern`

  * Value type is <<string,string>>
  * There is no default value for this setting.

A regex expression to use as value delimiter for parsing out key-value pairs.
Useful to define multi-character value delimiters.
Setting the `value_split_pattern` options will take precedence over the `value_split option`.

Note that you should avoid using captured groups in your regex and you should be
cautious with lookaheads or lookbehinds and positional anchors.

See `field_split_pattern` for examples.

[id="plugins-{type}s-{plugin}-whitespace"]
===== `whitespace`

  * Value can be any of: `lenient`, `strict`
  * Default value is `lenient`

An option specifying whether to be _lenient_ or _strict_ with the acceptance of unnecessary
whitespace surrounding the configured value-split sequence.

By default the plugin is run in `lenient` mode, which ignores spaces that occur before or
after the value-splitter. While this allows the plugin to make reasonable guesses with most
input, in some situations it may be too lenient.

You may want to enable `whitespace => strict` mode if you have control of the input data and
can guarantee that no extra spaces are added surrounding the pattern you have defined for
splitting values. Doing so will ensure that a _field-splitter_ sequence immediately following
a _value-splitter_ will be interpreted as an empty field.

[id="plugins-{type}s-{plugin}-common-options"]
include::{include_path}/{type}.asciidoc[]
