我们如何检查日志 output 是否在 Rails 4 中使用 STDOUT？

Question

In Rails, we can put this in development.rb if we are outputting the logs in the console:

config.logger = ActiveSupport::Logger.new(STDOUT)

So in Rails 5.x we can check if the log output is using STDOUT by using the code below:

# Returns true if the logger destination matches one of the sources which is STDOUT
ActiveSupport::Logger.logger_outputs_to?(Rails.logger, STDOUT)

Here's the documentation: https://github.com/rails/rails/blob/492b9b413d3aa3a9bf3bf986ae25c7f90ec1ab62/activesupport/lib/active_support/logger.rb#L16

My question now is how can we check if the log output is using STDOUT in Rails 4? Because this script ActiveSupport::Logger.logger_outputs_to? is not available in Rails 4.

Any ideas on this? Your help would be greatly appreciated. Thanks.

Answer 1

Since the ActiveSupport::Logger.logger_outputs_to?() is not available in Rails 4, I just created a function.

def self.logger_stdout
   logdev = ::Rails.logger.instance_variable_get(:@logdev)
   logger_source = logdev.dev if logdev.respond_to?(:dev)
   sources = [$stdout]
   found = sources.any? { |source| source == logger_source }
end