From: Chuck Remes <cremes.devlist@...>
Date: 2009-07-22T01:55:46+09:00
Subject: Re: Best practice question: logging


On Jul 21, 2009, at 9:50 AM, Pito Salas wrote:

> I want to sprinkle my code (Ruby, not Rails) liberally with logging
> calls so that when things go wrong I can see what happened.
>
> - is Ruby's Logger class the best practice to use, or is there another
> that's cooler? For example it looks like Logger is not that flexible
> about changing the format of log entries.
>
> - Is it better to define a global $Logger variable to hold the new
> Logger object across classes and methods, or bettor to do a @l =
> Logger.new(STDOUT) in each class's initializer?
>
> - how do I minimize the overhead when logging is OFF?
>
> - is one of these idioms faster than the other:
>
> if debugging
>   @l.debug("wow, what was that?"
> end
>
> @l.debug("wow, what was that?" if debugging
>
> @l.debug # no condition, just set   @l.level = Logger::ERROR
>
> Any other tips or pointers would be greatly appreciated!

I asked this same question about a year ago and got lots of help. Here  
is what I created:

http://gist.github.com/151454

I didn't write a lot of documentation in these classes and modules.  
Hopefully the concepts are clear enough from the code provided.

Logging is a pretty interesting process in my opinion. You may just  
write messages to STDOUT, to a file, to a network socket, or all of  
the above. Also, sometimes you want to disable logging but adding  
"logger.log("some message") unless logger.disabled?" all over the  
place is very ugly. As such, I use the Null Object pattern so you can  
"switch out" the logging class behind the scenes to one that just  
drops all messages.

For live logging, you call Logger.make_live (class method). To disable  
logging, Logger.make_null.

If you have specific questions on this code, reply back. I haven't  
looked at in since I wrote it 1+ years ago but I'm sure I can answer  
any questions that arise.

cr