api-plugin-helper-event_emitter.md

Plugin Helper: Event Emitter

The event_emitter plugin helper introduces the router method to the plugin.

Here is an example:

require 'fluent/plugin/output'

module Fluent::Plugin
  class RelabelOutput < Output
    Fluent::Plugin.register_output('relabel', self)
    helpers :event_emitter

    def multi_workers_ready?
      true
    end

    def process(tag, es)
      router.emit_stream(tag, es)
    end
  end
end

Methods

router

This method returns a Fluent::EventRouter instance.

Code example:

# emit event
router.emit(tag, time, record)

# emit event stream
router.emit_stream(tag, es)

# emit error event
begin
  # do something
rescue => error
  # Route event to @ERROR label or
  # log error message when @ERROR label is not defined in configuration
  router.emit_error_event(tag, time, record, error)
end

Plugins using event_emitter

• All input plugins
• All filter plugins
• out_exec
• out_relabel
• out_copy
• out_roundrobin

If this article is incorrect or outdated, or omits critical information, please let us know. Fluentd is an open-source project under Cloud Native Computing Foundation (CNCF). All components are available under the Apache 2 License.