Using Native Bindings with Ruby Enterprise Edition

I recently started using Passenger and Ruby Enterprise Edition to run my Rails apps.

“It was just another day at the office, until suddenly…” I wanted to run Warehouse. It turns out that things get (just) slightly hairy when you need to use the native bindings for a library, in this case Subversion/SWIG.

I ran rake warehouse:bootstrap without incident, but as soon as I submitted the ‘install’ form, it died. This is what I found in the log:

ActionView::TemplateError (/opt/ruby-enterprise/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/dependencies.rb:478:in `const_missing': uninitialized constant Repository::Svn) on line #23 of repositories/index.html.erb:
20:

21:     <%= link_to h(repo.name), hosted_url(repo, :admin) %>
22:     <%= repo.path %>
23:   <% if repo.sync? %>
24:   <% unless repo.sync_progress == 100 %>
25:
26:


    /srv/rails/entp-warehouse-78376218f92e6bdf8b72993d9caa384e5d4a5c66/vendor/plugins/expiring_attr_reader/lib/expiring_attr_reader.rb:32:in `silo'
    /srv/rails/entp-warehouse-78376218f92e6bdf8b72993d9caa384e5d4a5c66/app/models/repository.rb:137:in `retrieve_silo'
    (eval):1:in `silo'
    /srv/rails/entp-warehouse-78376218f92e6bdf8b72993d9caa384e5d4a5c66/app/models/repository.rb:100:in `eval'
    /srv/rails/entp-warehouse-78376218f92e6bdf8b72993d9caa384e5d4a5c66/vendor/plugins/expiring_attr_reader/lib/expiring_attr_reader.rb:32:in `silo'
    /srv/rails/entp-warehouse-78376218f92e6bdf8b72993d9caa384e5d4a5c66/app/models/repository.rb:100:in `sync?'
    /srv/rails/entp-warehouse-78376218f92e6bdf8b72993d9caa384e5d4a5c66/app/views/repositories/index.html.erb:23:in `_run_erb_47app47views47repositories47index46html46erb'
    /srv/rails/entp-warehouse-78376218f92e6bdf8b72993d9caa384e5d4a5c66/app/views/repositories/index.html.erb:19:in `each'
    /srv/rails/entp-warehouse-78376218f92e6bdf8b72993d9caa384e5d4a5c66/app/views/repositories/index.html.erb:19:in `_run_erb_47app47views47repositories47index46html46erb'
...

Naturally I had installed the bindings using sudo apt-get install libsvn-ruby1.8 so they were available to the default Ruby (located in /usr/lib/ruby), but not Ruby Enterprise Edition (located in /opt/ruby-enterprise), which the application runs on.

My solution was to simply symlink the Subversion bindings into Ruby Enterprise Edition. A quick look in the libsvn-ruby package (sudo dpkg -L libsvn-ruby1.8) shows us what we’re dealing with:

...
/usr/lib/ruby/1.8/i486-linux
/usr/lib/ruby/1.8/i486-linux/svn
/usr/lib/ruby/1.8/i486-linux/svn/ext
/usr/lib/ruby/1.8/i486-linux/svn/ext/core.so
/usr/lib/ruby/1.8/i486-linux/svn/ext/client.so
/usr/lib/ruby/1.8/i486-linux/svn/ext/delta.so
/usr/lib/ruby/1.8/i486-linux/svn/ext/fs.so
/usr/lib/ruby/1.8/i486-linux/svn/ext/ra.so
/usr/lib/ruby/1.8/i486-linux/svn/ext/repos.so
/usr/lib/ruby/1.8/i486-linux/svn/ext/wc.so
/usr/lib/ruby/1.8/svn
/usr/lib/ruby/1.8/svn/client.rb
/usr/lib/ruby/1.8/svn/core.rb
/usr/lib/ruby/1.8/svn/delta.rb
/usr/lib/ruby/1.8/svn/error.rb
/usr/lib/ruby/1.8/svn/fs.rb
/usr/lib/ruby/1.8/svn/info.rb
/usr/lib/ruby/1.8/svn/ra.rb
/usr/lib/ruby/1.8/svn/repos.rb
/usr/lib/ruby/1.8/svn/util.rb
/usr/lib/ruby/1.8/svn/wc.rb
...

The key directories are: /usr/lib/ruby/1.8/i486-linux/svn and /usr/lib/ruby/1.8/svn. So we’ll make them available to /opt/ruby-enterprise like so:

cd /opt/ruby-enterprise/lib/ruby/1.8
sudo ln -s /usr/lib/ruby/1.8/svn
cd /opt/ruby-enterprise/lib/ruby/site_ruby/1.8/i686-linux
sudo ln -s /usr/lib/ruby/1.8/i486-linux/svn

After that, just restart Apache (apache2ctl restart), and it should be working. Note, a simple touch tmp/restart.txt won’t work, because that doesn’t reload the libraries. You actually need the /opt/ruby-enterprise/ruby process to restart.

Theoretically this same approach should work for any native bindings you need to be available to Ruby Enterprise Edition.