grep

Milestone: 3

This is a community-contributed plugin! It does not ship with logstash by default, but it is easy to install! To use this, you must have installed the contrib plugins package.

Grep filter. Useful for dropping events you don’t want to pass, or adding tags or fields to events that match.

Events not matched are dropped. If ‘negate’ is set to true (defaults false), then matching events are dropped.

Synopsis

This is what it might look like in your config file:
filter {
  grep {
    add_field => ... # hash (optional), default: {}
    add_tag => ... # array (optional), default: []
    drop => ... # boolean (optional), default: true
    ignore_case => ... # boolean (optional), default: false
    match => ... # hash (optional), default: {}
    negate => ... # boolean (optional), default: false
    remove_field => ... # array (optional), default: []
    remove_tag => ... # array (optional), default: []
  }
}

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 {
  grep {
    add_field => { "foo_%{somefield}" => "Hello world, from %{host}" }
  }
}

# You can also add multiple fields at once:

filter {
  grep {
    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 {
  grep {
    add_tag => [ "foo_%{somefield}" ]
  }
}

# You can also add multiple tags at once:
filter {
  grep {
    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).

drop

  • Value type is boolean
  • Default value is true

Drop events that don’t match

If this is set to false, no events will be dropped at all. Rather, the requested tags and fields will be added to matching events, and non-matching events will be passed through unchanged.

exclude_tags DEPRECATED

  • DEPRECATED WARNING: This config item is deprecated. It may be removed in a further version.
  • Value type is array
  • Default value is []

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

ignore_case

  • Value type is boolean
  • Default value is false

Use case-insensitive matching. Similar to ‘grep -i’

If enabled, ignore case distinctions in the patterns.

match

  • Value type is hash
  • Default value is {}

A hash of matches of field => regexp. If multiple matches are specified, all must match for the grep to be considered successful. Normal regular expressions are supported here.

For example:

filter {
  grep {
    match => { "message" => "hello world" }
  }
}

The above will drop all events with a message not matching “hello world” as a regular expression.

negate

  • Value type is boolean
  • Default value is false

Negate the match. Similar to ‘grep -v’

If this is set to true, then any positive matches will result in the event being cancelled and dropped. Non-matching will be allowed through.

remove_field

  • 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 {
  grep {
    remove_field => [ "foo_%{somefield}" ]
  }
}

# You can also remove multiple fields at once:

filter {
  grep {
    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 {
  grep {
    remove_tag => [ "foo_%{somefield}" ]
  }
}

# You can also remove multiple tags at once:

filter {
  grep {
    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.

tags DEPRECATED

  • DEPRECATED WARNING: This config item is deprecated. It may be removed in a further version.
  • Value type is array
  • Default value is []

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

type DEPRECATED

  • DEPRECATED WARNING: This config item is deprecated. It may be removed in a further version.
  • 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.


This is documentation from lib/logstash/filters/grep.rb