kv

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:

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 &.

 

Synopsis

This plugin supports the following configuration options:

Required configuration options:

kv {
}

Available configuration options:

Details

 

add_field

  • 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 {
  kv {
    add_field => { "foo_%{somefield}" => "Hello world, from %{host}" }
  }
}
# You can also add multiple fields at once:
filter {
  kv {
    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

  • 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 {
  kv {
    add_tag => [ "foo_%{somefield}" ]
  }
}
# You can also add multiple tags at once:
filter {
  kv {
    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).

default_keys

  • Value type is 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.

filter {
  kv {
    default_keys => [ "from", "logstash@example.com",
                     "to", "default@dev.null" ]
  }
}

exclude_keys

  • Value type is 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:

filter {
  kv {
    exclude_keys => [ "from", "to" ]
  }
}

exclude_tags (DEPRECATED)

  • DEPRECATED WARNING: This configuration item is deprecated and may not be available in future versions.
  • Value type is array
  • Default value is []

Only handle events without all/any (controlled by exclude_any config option) of these tags. Optional.

field_split

  • Value type is string
  • Default value is " "

A string of characters to use as 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:

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

include_keys

  • Value type is 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:

filter {
  kv {
    include_keys => [ "from", "to" ]
  }
}

periodic_flush

  • Value type is boolean
  • Default value is false

Call the filter flush method at regular interval. Optional.

prefix

  • Value type is string
  • Default value is ""

A string to prepend to all of the extracted keys.

For example, to prepend arg_ to all keys:

filter { kv { prefix => "arg_" } }

remove_field

  • Value type is array
  • Default value is []

If this filter is successful, remove arbitrary fields from this event. Example:

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

  • 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 {
  kv {
    remove_tag => [ "foo_%{somefield}" ]
  }
}
# You can also remove multiple tags at once:
filter {
  kv {
    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

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

The field to perform key=value searching on

For example, to process the not_the_message field:

filter { kv { source => "not_the_message" } }

tags (DEPRECATED)

  • DEPRECATED WARNING: This configuration item is deprecated and may not be available in future versions.
  • Value type is array
  • Default value is []

Only handle events with all/any (controlled by include_any config option) of these tags. Optional.

target

  • Value type is 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:

filter { kv { target => "kv" } }

trim

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

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 \.

For example, to strip <, >, [, ] and , characters from values:

filter {
  kv {
    trim => "<>\[\],"
  }
}

trimkey

  • Value type is 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 \.

For example, to strip < > [ ] and , characters from keys:

filter {
  kv {
    trimkey => "<>\[\],"
  }
}

type (DEPRECATED)

  • DEPRECATED WARNING: This configuration item is deprecated and may not be available in future versions.
  • Value type is string
  • Default value is ""

Note that all of the specified routing options (type,tags,exclude_tags,include_fields, exclude_fields) must be met in order for the event to be handled by the filter. The type to act on. If a type is given, then this filter will only act on messages with the same type. See any input plugin’s "type" attribute for more. Optional.

value_split

  • Value type is string
  • Default value is "="

A string of characters to use as delimiters for identifying key-value relations.

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:

filter { kv { value_split => ":" } }