How to log user_name in Rails?

Question

I use Devise in Rails 3. I want to see name of current_user in production.log.

I would like to configure rails like this:

config.log_tags = [:user_na         


        

Answer 1

I'm using Swards solution and it works like a charm. However using begin..rescue instead of Hash#has_key? is a performance killer

require 'benchmark/ips'

good_hash = { 'warden.user.admin_user.key' => [[1]]}
bad_hash = {}

Benchmark.ips do |x|
  x.report('begin+rescue good hash') { good_hash['warden.user.admin_user.key'][0][0] }
  x.report('has_key good hash') do
    good_hash.has_key?('warden.user.admin_user.key') &&
        good_hash['warden.user.admin_user.key'][0][0]
  end

  x.report('begin+rescue bad hash') { bad_hash['warden.user.admin_user.key'][0][0] rescue nil }
  x.report('has_key bad hash') do
    if bad_hash.has_key?('warden.user.admin_user.key')
      bad_hash['warden.user.admin_user.key'][0][0]
    end
  end

  # Compare the iterations per second of the various reports!
  x.compare!
end

Results speak for themselves

Comparison:
    has_key bad hash:  4870164.1 i/s
begin+rescue good hash:  3544134.7 i/s - 1.37x slower
   has_key good hash:  2127500.6 i/s - 2.29x slower
begin+rescue bad hash:     4468.2 i/s - 1089.95x slower