class ActiveSupport::Notifications::Instrumenter

Instrumenters are stored in a thread local.

Attributes

Public Class Methods

# File activesupport/lib/active_support/notifications/instrumenter.rb, line 12
def initialize(notifier)
  unless notifier.respond_to?(:build_handle)
    notifier = LegacyHandle::Wrapper.new(notifier)
  end

  @id       = unique_id
  @notifier = notifier
end

Public Instance Methods

build_handle (name, payload)

Returns a “handle” for an event with the given name and payload.

start and finish must each be called exactly once on the returned object.

Where possible, it’s best to use instrument, which will record the start and finish of the event and correctly handle any exceptions. build_handle is a low-level API intended for cases where using instrument isn’t possible.

See ActiveSupport::Notifications::Fanout::Handle.

# File activesupport/lib/active_support/notifications/instrumenter.rb, line 78
def build_handle(name, payload)
  @notifier.build_handle(name, @id, payload)
end

finish (name, payload)

Send a finish notification with name and payload.

# File activesupport/lib/active_support/notifications/instrumenter.rb, line 92
def finish(name, payload)
  @notifier.finish name, @id, payload
end

finish_with_state (listeners_state, name, payload)

# File activesupport/lib/active_support/notifications/instrumenter.rb, line 96
def finish_with_state(listeners_state, name, payload)
  @notifier.finish name, @id, payload, listeners_state
end

instrument (name, payload = {}) { |payload| ... }

Given a block, instrument it by measuring the time taken to execute and publish it. Without a block, simply send a message via the notifier. Notice that events get sent even if an error occurs in the passed-in block.

# File activesupport/lib/active_support/notifications/instrumenter.rb, line 54
def instrument(name, payload = {})
  handle = build_handle(name, payload)
  handle.start
  begin
    yield payload if block_given?
  rescue Exception => e
    payload[:exception] = [e.class.name, e.message]
    payload[:exception_object] = e
    raise e
  ensure
    handle.finish
  end
end

start (name, payload)

Send a start notification with name and payload.

# File activesupport/lib/active_support/notifications/instrumenter.rb, line 87
def start(name, payload)
  @notifier.start name, @id, payload
end