For other versions, see theVersioned 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.
Execute ruby code. This filter accepts inline ruby code or a ruby file.The two options are mutually exclusive and have slightly different ways of working,which are described below.
To inline ruby in your filter, place all code in the code
option. This code will be executed for every event the filter receives. You can also place ruby code in the init
option - it will be executed only once during the plugin’s register phase.
For example, to cancel 90% of events, you can do this:
filter { ruby { # Cancel 90% of events code => "event.cancel if rand <= 0.90" }}
If you need to create additional events, you must use a specific syntax new_event_block.call(event)
like in this example duplicating the input event
filter { ruby { code => "new_event_block.call(event.clone)" }}
As the inline code can become complex and hard to structure inside of a text string in code
, it’s then preferrable to place the Ruby code in a .rb file, using the path
option.
filter { ruby { # Cancel 90% of events path => "/etc/logstash/drop_percentage.rb" script_params => { "percentage" => 0.9 } }}
The ruby script file should define the following methods:
register(params)
: An optional register method that receives the key/value hash passed in the script_params
configuration optionfilter(event)
: A mandatory Ruby method that accepts a Logstash event and must return an array of eventsBelow is an example implementation of the drop_percentage.rb
ruby script that drops a configurable percentage of events:
# the value of `params` is the value of the hash passed to `script_params`# in the logstash configurationdef register(params) @drop_percentage = params["percentage"]end# the filter method receives an event and must return a list of events.# Dropping an event means not including it in the return array,# while creating new ones only requires you to add a new instance of# LogStash::Event to the returned arraydef filter(event) if rand >= @drop_percentage return [event] else return [] # return empty array to cancel event endend
To validate the behaviour of the filter
method you implemented,the Ruby filter plugin provides an inline test framework where youcan assert expectations.The tests you define will run when the pipeline is created and willprevent it from starting if a test fails.
You can also verify if the tests pass using the logstash -t
flag.
For example above, you can write at the bottom of the drop_percentage.rb
ruby script the following test:
def register(params) # ..enddef filter(event) # ..endtest "drop percentage 100%" do parameters do { "percentage" => 1 } end in_event { { "message" => "hello" } } expect("drops the event") do |events| events.size == 0 endend
We can now test that the ruby script we’re using is implemented correctly:
% bin/logstash -e "filter { ruby { path => '/etc/logstash/drop_percentage.rb' script_params => { 'drop_percentage' => 0.5 } } }" -t[2017-10-13T13:44:29,723][INFO ][logstash.filters.ruby.script] Test run complete {:script_path=>"/etc/logstash/drop_percentage.rb", :results=>{:passed=>1, :failed=>0, :errored=>0}}Configuration OK[2017-10-13T13:44:29,887][INFO ][logstash.runner ] Using config.test_and_exit mode. Config Validation Result: OK. Exiting Logstash
This plugin supports the following configuration options plus the Common Options described later.
Also see Common Options for a list of options supported by allfilter plugins.
path
.The code to execute for every event.You will have an event
variable available that is the event itself. See the Event API for more information.
Any code to execute at logstash startup-time
code
.The path of the ruby script file that implements the filter
method.
{}
A key/value hash with parameters that are passed to the register methodof your ruby script file defined in path
.
_rubyexception
Tag to add to events in case the ruby code (either inline or file based)causes an exception.
The following configuration options are supported by all filter plugins:
Setting | Input type | Required |
---|---|---|
No |
||
No |
||
No |
||
No |
||
No |
||
No |
||
No |
{}
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 { ruby { add_field => { "foo_%{somefield}" => "Hello world, from %{host}" } }}
# You can also add multiple fields at once:filter { ruby { 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 thevalue above and the %{host}
piece replaced with that value from theevent. The second example would also add a hardcoded field.
[]
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 { ruby { add_tag => [ "foo_%{somefield}" ] }}
# You can also add multiple tags at once:filter { ruby { 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).
true
Disable or enable metric logging for this specific plugin instanceby default we record all the metrics we can, but you can disable metrics collectionfor a specific plugin.
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 usefulwhen you have two or more plugins of the same type, for example, if you have 2 ruby filters.Adding a named ID in this case will help in monitoring Logstash when using the monitoring APIs.
filter { ruby { id => "ABC" }}
false
Call the filter flush method at regular interval.Optional.
[]
If this filter is successful, remove arbitrary fields from this event.Example:
filter { ruby { remove_field => [ "foo_%{somefield}" ] }}
# You can also remove multiple fields at once:filter { ruby { 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 secondexample would remove an additional, non-dynamic field.
[]
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 { ruby { remove_tag => [ "foo_%{somefield}" ] }}
# You can also remove multiple tags at once:filter { ruby { 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 examplewould remove a sad, unwanted tag as well.