Class ActiveSupport::LogSubscriber
In: lib/active_support/log_subscriber/test_helper.rb
lib/active_support/log_subscriber.rb
Parent: Object

ActiveSupport::LogSubscriber is an object set to consume ActiveSupport::Notifications with the sole purpose of logging them. The log subscriber dispatches notifications to a registered object based on its given namespace.

An example would be Active Record log subscriber responsible for logging queries:

  module ActiveRecord
    class LogSubscriber < ActiveSupport::LogSubscriber
      def sql(event)
        "#{event.payload[:name]} (#{event.duration}) #{event.payload[:sql]}"
      end
    end
  end

And it‘s finally registered as:

  ActiveRecord::LogSubscriber.attach_to :active_record

Since we need to know all instance methods before attaching the log subscriber, the line above should be called after your ActiveRecord::LogSubscriber definition.

After configured, whenever a "sql.active_record" notification is published, it will properly dispatch the event (ActiveSupport::Notifications::Event) to the sql method.

Log subscriber also has some helpers to deal with logging and automatically flushes all logs when the request finishes (via action_dispatch.callback notification) in a Rails environment.

Methods

Classes and Modules

Module ActiveSupport::LogSubscriber::TestHelper

Constants

CLEAR = "\e[0m"   Embed in a String to clear all previous ANSI sequences.
BOLD = "\e[1m"
BLACK = "\e[30m"   Colors
RED = "\e[31m"
GREEN = "\e[32m"
YELLOW = "\e[33m"
BLUE = "\e[34m"
MAGENTA = "\e[35m"
CYAN = "\e[36m"
WHITE = "\e[37m"

Public Class methods

Public Instance methods

Protected Instance methods

Set color by using a string or one of the defined constants. If a third option is set to true, it also adds bold to the string. This is based on the Highline implementation and will automatically append CLEAR to the end of the returned String.

[Validate]