[LRUG] Rails log_tags in production

[Andrew Stewart]

Hello LRUG!

I am trying to log the current user id in a Rails app via the following configuration:

  # config/environments/{development,production}.rb
  config.log_tags = [
    lambda { |request|
      session_key = Rails.application.config.session_options[:key]
      session_data = request.cookie_jar.signed[session_key]
      user_id = session_data['current_person_id']
      user_id || 'public'
    }
  ]

This works fine in development but in production, although the site works perfectly for a user, Pingdom immediately reports a 500 error and unicorn.stderr.log shows:

  app error: undefined method `[]' for nil:NilClass (NoMethodError)
  /path/to/my/app/releases/20160717162528/config/environments/production.rb:49

Line 49 is the `user_id = session_data['current_person_id']` one above.

In production I'm using Rails 3.2 and Unicorn 4.2.0 (behind Nginx 1.6.2).

Does anyone know why this doesn't work in production for Pingdom's bot?

Many thanks in advance!

Yours,

Andy Stewart