api-plugin-helper-inject.md

Plugin Helper: Inject

The inject plugin helper injects values into events according to the configuration.

Here is an example:

require 'fluent/plugin/filter'

module Fluent::Plugin
  class ExampleFilter < Filter
    Fluent::Plugin.register_filter('example', self)

    # 1. Load inject helper
    helpers :inject

    # Omit `configure`, `shutdown` and other plugin APIs

    def filter(tag, time, record)
      # 2. Inject values into `record`
      new_record = inject_values_to_record(tag, time, record)
      # edit new_record ...
      new_record
    end
  end
end

For more details, see Inject section.

Methods

inject_values_to_record(tag, time, record)

This method injects values to the given record and returns the new record.

• tag: the tag of the event
• time: event timestamp
• record: event record

Example:

def filter(tag, time, record)
  new_record = inject_values_to_record(tag, time, record)
  # edit new_record ...
  new_record
end

inject_values_to_event_stream(tag, es)

This method injects values into the given event stream and returns the new event stream.

• tag: the tag of the event
• es: event stream

Example:

def process(tag, es)
  new_es = inject_values_to_event_stream(tag, es)
  # do something using new_es
end

Plugins using inject

• filter_stdout
• out_exec
• out_exec_filter
• out_file
• out_stdout

If this article is incorrect or outdated, or omits critical information, please let us know.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.