Rails logger formatting - insert method name calling logger method - ruby

Question

I want to insert name of the method calling the logger methods into my log files. Not the whole stack trace, but the class, method and/or line number would be great.
In any method, one can use caller to get an array of strings, each of which contains the file, line number and method name. I've come up with a pretty awful kludge using regexes and Enumerable#find to try to return the first non-logger stack frame. I guess it works, but if the locations of the logging Ruby files change in a different version or Rails, or I name my files something to do with logs, it will break. Same with if I take a given index from the top of the stack (I did this at first, then refactored one thing and naturally it gave me the wrong frame).
Note that I'm not looking to just log the controller or action, as those can be retrieved easily. Mostly this is for stuff in the lib/ directory.
Isn't there an easy way to do this? I don't want to have to pass in __method__ every time I make a logging statement.

Answer 1

I've looked all over at different solutions for capturing the exact place (file, line number, method name) where I invoke any given logger instance method from within my rails app. To do this, you need to override Logger's format_message method, and a good place to do this is in your rails project's config/environment.rb file.
This is what I've come up with, which is good enough for me ;o)
class Logger
def format_message(severity, timestamp, progname, msg)
line = ''
Kernel.caller.each{|entry|
if (entry.include? Rails.root.to_s)
line = " #{entry.gsub(Rails.root.to_s,'').gsub(/\/(.+)\:in `(.+)'/, "\\1 -> \\2")}"
break
end
}
"[#{timestamp.strftime("%Y%m%d.%H:%M:%S")}] #{severity}#{line}: #{msg}\n"
end
end
Kernel.caller holds an enumerable array of the entire backtrace. If you look at it in its entirety, you'll see most calls are internal inside of a gem somewhere well outside your project. I've found that by looping through the Kernel.caller until I find the first place that includes my Rails.root, I can get the line with the information I want to parse.
Example:
If I call Rails.logger.debug("Streamer class started!") from the start method of my Streamer class, the raw entry would look like this:
/Users/chikoon/www/my_rails_app/lib/streamer.rb:7:in `start'
so by the time it makes it through my formatter, I've got the timestamp, severity mode, the file path, line number, method name, and message:
[20140919.19:23:44] DEBUG lib/streamer.rb:7 -> start: Streamer class started!
I hope that helps get your wheels turning.

Answer 2

How about setting up log_tags to call the __method__?
Blog::Application.configure do
config.log_tags = [lambda { |req| __method__ }]
end