116 lines
3.6 KiB
Ruby
116 lines
3.6 KiB
Ruby
require 'active_support/core_ext/class/inheritable_attributes'
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require 'active_support/notifications'
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module Rails
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# Rails::LogSubscriber is an object set to consume ActiveSupport::Notifications
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# on initialization with solely purpose of logging. The log subscriber dispatches
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# notifications to a regirested object based on its given namespace.
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#
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# An example would be ActiveRecord log subscriber responsible for logging queries:
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#
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# module ActiveRecord
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# class Railtie
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# class LogSubscriber < Rails::LogSubscriber
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# def sql(event)
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# "#{event.payload[:name]} (#{event.duration}) #{event.payload[:sql]}"
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# end
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# end
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# end
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# end
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#
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# It's finally registed as:
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#
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# Rails::LogSubscriber.add :active_record, ActiveRecord::Railtie::LogSubscriber.new
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#
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# So whenever a "sql.active_record" notification arrive to Rails::LogSubscriber,
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# it will properly dispatch the event (ActiveSupport::Notifications::Event) to
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# the sql method.
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#
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# This is useful because it avoids spanning several log subscribers just for logging
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# purposes(which slows down the main thread). Besides of providing a centralized
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# facility on top of Rails.logger.
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#
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# Log subscriber also has some helpers to deal with logging and automatically flushes
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# all logs when the request finishes (via action_dispatch.callback notification).
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class LogSubscriber
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mattr_accessor :colorize_logging
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self.colorize_logging = true
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# Embed in a String to clear all previous ANSI sequences.
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CLEAR = "\e[0m"
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BOLD = "\e[1m"
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# Colors
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BLACK = "\e[30m"
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RED = "\e[31m"
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GREEN = "\e[32m"
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YELLOW = "\e[33m"
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BLUE = "\e[34m"
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MAGENTA = "\e[35m"
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CYAN = "\e[36m"
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WHITE = "\e[37m"
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def self.add(namespace, log_subscriber, notifier = ActiveSupport::Notifications)
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log_subscribers << log_subscriber
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@flushable_loggers = nil
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log_subscriber.public_methods(false).each do |event|
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notifier.subscribe("#{event}.#{namespace}") do |*args|
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next if log_subscriber.logger.nil?
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begin
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log_subscriber.send(event, ActiveSupport::Notifications::Event.new(*args))
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rescue Exception => e
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Rails.logger.error "Could not log #{args[0].inspect} event. #{e.class}: #{e.message}"
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end
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end
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end
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end
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def self.log_subscribers
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@log_subscribers ||= []
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end
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def self.flushable_loggers
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@flushable_loggers ||= begin
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loggers = log_subscribers.map(&:logger)
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loggers.uniq!
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loggers.select { |l| l.respond_to?(:flush) }
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end
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end
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# Flush all log_subscribers' logger.
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def self.flush_all!
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flushable_loggers.each(&:flush)
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end
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# By default, we use the Rails.logger for logging.
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def logger
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Rails.logger
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end
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protected
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%w(info debug warn error fatal unknown).each do |level|
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class_eval <<-METHOD, __FILE__, __LINE__ + 1
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def #{level}(*args, &block)
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return unless logger
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logger.#{level}(*args, &block)
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end
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METHOD
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end
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# Set color by using a string or one of the defined constants. If a third
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# option is set to true, it also adds bold to the string. This is based
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# on Highline implementation and it automatically appends CLEAR to the end
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# of the returned String.
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#
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def color(text, color, bold=false)
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return text unless colorize_logging
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color = self.class.const_get(color.to_s.upcase) if color.is_a?(Symbol)
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bold = bold ? BOLD : ""
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"#{bold}#{color}#{text}#{CLEAR}"
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end
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end
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end
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