ActionMailer and mod_fcgi
Lately, I have been playing around a lot with Ruby on Rails and am currently finishing my first full-fledged application. While I am using WEBrick directly launched from my Eclipse development IDE in my development environment the production site is currently using Apache + mod_fcgi to run the application. This is where all the problems started. ;-)
The application sends out e-mail notifications (using ActionMailer) for various state transitions, which worked flawlessly on the development machine. In the production setting, however, sending mails failed complaining that it cannot find the associated mail template:
ActionView::MissingTemplate (Missing template event_mailer/approval_requested_notification.erb in view path app/views): app/models/event_observer.rb:3:in `after_enter_awaiting_approval' /usr/lib/ruby/1.8/observer.rb:185:in `notify_observers' /usr/lib/ruby/1.8/observer.rb:184:in `each' /usr/lib/ruby/1.8/observer.rb:184:in `notify_observers' (eval):10:in `create_or_update_without_callbacks' app/controllers/event_controller.rb:71:in `request_approval' public/dispatch.fcgi:24
Well, after putting some thought into possible differences between development and production and ruling out any relevant configuration differences in config/* all that remained was the fact that dev uses WEBrick while production uses mod_fcgi. One thought lead to another and it turned out that WEBrick sets the application root as the current working directory during startup while mod_fcgi does not.
So, the workaround is simple: Set the current working directory to the application root in config/environment.rb, such as:
Dir.chdir(File.dirname(__FILE__) << '/../')