RubyInline in Shared Rails Environments

As an end-to-end web production company, we have a vested interest in making Rails applications easier to deploy for both development and production purposes. We’ve developed Tyrant, a Rails app for running Rails apps, and we’re eagerly watching as new solutions are created and refined.

But it’s a new market, and current solutions are not without their share of obstacles. In working with both Tyrant and Phusion Passenger, we’ve encountered difficulties running applications that use RubyInline to embed C into Ruby code (e.g., ImageScience, my image processing library of choice). Try to start up an app that uses RubyInline code in a shared environment, and you might encounter the following error:

 /Library/Ruby/Gems/1.8/gems/RubyInline-3.6.7/lib/inline.rb:325:in `mkdir': Permission denied - /home/users/www-data/.ruby_inline (Errno::EACCES)

RubyInline uses the home directory of the user who started the server to compile the inline code; problems occur when the current process is owned by a different user. “Simple,” you think. “I’ll just open that directory up to everybody.” Not so fast, hotshot. Try to start the app again, and you get the following:

 /home/users/www-data/.ruby_inline is insecure (40777). It may not be group or world writable. Exiting.

Curses! Fortunately, VigetExtend is here to help. Drop this into your environment-specific config file:

 temp = Tempfile.new('ruby_inline', '/tmp') dir = temp.path temp.delete Dir.mkdir(dir, 0755) ENV['INLINEDIR'] = dir 

We use the Tempfile library to generate a guaranteed-unique filename in the /tmp directory, prepended with “ruby_inline.” After storing the filename, we delete the tempfile and create a directory with the proper permissions in its place. We then store the directory path in the INLINEDIR environment variable, so that RubyInline knows to use it to compile.