How can I log Rails errors into a separate log file?

Question

Our production logs are long and contain a lot more than just errors. I'd like a second log file with just the errors/exceptions in.

Is this possible?

We're using rails 2.x

Thanks.

possible duplicate of [How to log something in Rails in an independent log file?](http://stackoverflow.com/questions/337739/how-to-log-something-in-rails-in-an-independent-log-file) — fl00r, Mar 29 '11 at 15:30
I don't think it's a duplicate - it's a different question. About how to automatically split the standard log files into more fine grained parts - instead of manually logging to a separate file. — Christopher Stott, Mar 29 '11 at 16:16

score 7 · Accepted Answer · edited May 14 '14 at 22:01

7

For example, to log all ActiveRecord::Base errors in a file called log/exceptions.log

new_logger = Logger.new('log/exceptions.log')
new_logger.level = Logger::ERROR
new_logger.error('THIS IS A NEW EXCEPTION!')

ActiveRecord::Base.logger = new_logger

For controllers and view(because ActionView logger doesn't have it's own logger, so it depends on the ActionController logger):

ActionController::Base.logger = new_logger

edited May 14 '14 at 22:01

Jenner La Fave

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answered Mar 29 '11 at 15:33

Mike Lewis

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1

Is there a way to do this for exceptions in general? or to maybe log erb / controller errors to their own files too? – Christopher Stott Mar 29 '11 at 16:13
Posted how to do controllers/views. – Mike Lewis Mar 29 '11 at 16:18
3

How is it going to have only the errors? You're clearly logging an info and it ends up in exceptions.log? – Khash May 26 '11 at 17:48
2

This answer does not answer the question. It is off topic. It tells how to log to different files from different app layers / modules, not how to log debug/info/error/warn etc. level messages in to separate files. – Szymon Jeż Jun 27 '13 at 14:15

score 7 · Answer 2 · edited Dec 20 '17 at 19:36

Try the following. Put the rescue_from method in your controller.

I haven't tested this. But maybe it puts you in the right direction

class ApplicationController < ActionController::Base
  rescue_from StandardError do |exception|
    new_logger = Logger.new('log/exceptions.log')
    new_logger.info('THIS IS A NEW EXCEPTION!')
    new_logger.info(exception.message)
    new_logger.info(exception.backtrace)
    # Raise it anyway because you just want to put it in the log
    raise exception
  end
end

If you use Rails 2.1 (also not tested)

class ApplicationController < ActionController::Base
  def rescue_action_in_public(exception)
    new_logger = Logger.new('log/exceptions.log')
    new_logger.info('THIS IS A NEW EXCEPTION!')
    new_logger.info(exception.message)
    new_logger.info(exception.backtrace)
    # Raise it anyway because you just want to put it in the log
    raise exception
  end
end

How can I log Rails errors into a separate log file?

2 Answers2

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