Getting module of caller in Ruby

Question

We have code to log data in our Ruby 1.8.6 web application. You call it roughly as follows: ``` $log.info("Some text here") ``` Now, in the logged output, I would like to include the module where that line appeared. I know that the `Kernel#caller` will give me an array where I can pull out the file and line number that the log line occurred, but I don't want that. I want the module, not the file name. The obvious solution is to modify the log line so that it reads like: ``` $log.info("Some text here", self.class.name) ``` and then parse the result. That's not going to work, though, because I am trying to extract this information in the default case. That is, I need the solution to work if the programmer forgot to specify the module, the second parameter to the log line. Is there any way to do this? If not, I will just have to make do with the `caller` array; most of our modules are in separate directories, so this would be an 80% solution. More complete example, please excuse minor sy…

Accepted Answer

Use call_stack.

First install it with RubyGems:

```
gem install call_stack
```

Then change log.rb to:

```
require 'rubygems'
require 'call_stack'

call_stack_on

module Log
  class Logger
    def info(msg, mod = '')
        mod = call_stack(2)[0][0] if mod == ''
        puts "Module: #{mod}  Msg: #{msg}"
    end
  end # class Logger
end # module Log
$log = Log::Logger.new
```

Works for me (Ruby 1.8.7).

```
$ ruby foo.rb
Module: Foo::Bar  Msg: I did something!
```

Getting module of caller in Ruby

Solution

Problem