subscribe

Registers a new event subscriber. The subscriber must respond to

emit(event: Hash)

The event hash will have the following keys:

name: String (The name of the event)
payload: Hash, Object (The payload of the event, or the event object itself)
tags: Hash (The tags of the event)
context: Hash (The context of the event)
timestamp: Float (The timestamp of the event, in nanoseconds)
source_location: Hash (The source location of the event, containing the filepath, lineno, and label)

An optional filter proc can be provided to only receive a subset of events:

Rails.event.subscribe(subscriber) { |event| event[:name].start_with?("user.") }
Rails.event.subscribe(subscriber) { |event| event[:payload].is_a?(UserEvent) }