require 'active_support/core_ext/module/attribute_accessors'
require 'active_support/core_ext/class/attribute'
module ActiveSupport
# 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 <tt>ActiveRecord::LogSubscriber</tt> 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.
class LogSubscriber
# Embed in a String to clear all previous ANSI sequences.
CLEAR = "\e[0m"
BOLD = "\e[1m"
# Colors
BLACK = "\e[30m"
RED = "\e[31m"
GREEN = "\e[32m"
YELLOW = "\e[33m"
BLUE = "\e[34m"
MAGENTA = "\e[35m"
CYAN = "\e[36m"
WHITE = "\e[37m"
mattr_accessor :colorize_logging
self.colorize_logging = true
class_attribute :logger
class << self
remove_method :logger
def logger
@logger ||= Rails.logger if defined?(Rails)
end
def attach_to(namespace, log_subscriber=new, notifier=ActiveSupport::Notifications)
log_subscribers << log_subscriber
@@flushable_loggers = nil
log_subscriber.public_methods(false).each do |event|
next if %w{ start finish }.include?(event.to_s)
notifier.subscribe("#{event}.#{namespace}", log_subscriber)
end
end
def log_subscribers
@@log_subscribers ||= []
end
def flushable_loggers
@@flushable_loggers ||= begin
loggers = log_subscribers.map(&:logger)
loggers.uniq!
loggers.select! { |l| l.respond_to?(:flush) }
loggers
end
end
# Flush all log_subscribers' logger.
def flush_all!
flushable_loggers.each { |log| log.flush }
end
end
def initialize
@event_stack = Hash.new { |h,id|
h[id] = Hash.new { |ids,name| ids[name] = [] }
}
super
end
def start(name, id, payload)
return unless logger
e = ActiveSupport::Notifications::Event.new(name, Time.now, nil, id, payload)
parent = @event_stack[id][name].last
parent << e if parent
@event_stack[id][name].push e
end
def finish(name, id, payload)
return unless logger
finished = Time.now
event = @event_stack[id][name].pop
event.end = finished
method = name.split('.').first
begin
send(method, event)
rescue Exception => e
logger.error "Could not log #{name.inspect} event. #{e.class}: #{e.message} #{e.backtrace}"
end
end
protected
%w(info debug warn error fatal unknown).each do |level|
class_eval <<-METHOD, __FILE__, __LINE__ + 1
def #{level}(progname = nil, &block)
logger.#{level}(progname, &block) if logger
end
METHOD
end
# 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.
#
def color(text, color, bold=false)
return text unless colorize_logging
color = self.class.const_get(color.upcase) if color.is_a?(Symbol)
bold = bold ? BOLD : ""
"#{bold}#{color}#{text}#{CLEAR}"
end
end
end