Rails - cannot run app: Unable to load the EventMachine C extension;

Question

When I run an app on Lion OS X, I get this error:

Unable to load the EventMachine C extension; To use the pure-ruby reactor, require 'em/pure_ruby'
/Users/adam/.rvm/gems/ruby-1.9.2-p290/gems/eventmachine-1.0.0/lib/eventmachine.rb:8:in `require': no such file to load -- rubyeventmachine (LoadError)
    from /Users/adam/.rvm/gems/ruby-1.9.2-p290/gems/eventmachine-1.0.0/lib/eventmachine.rb:8:in `<top (required)>'
    from /Users/adam/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler/runtime.rb:68:in `require'
    from /Users/adam/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler/runtime.rb:68:in `block (2 levels) in require'
    from /Users/adam/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler/runtime.rb:66:in `each'
    from /Users/adam/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler/runtime.rb:66:in `block in require'
    from /Users/adam/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler/runtime.rb:55:in `each'
    from /Users/adam/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler/runtime.rb:55:in `require'
    from /Users/adam/.rvm/gems/ruby-1.9.2-p290@global/gems/bundler-1.0.21/lib/bundler.rb:122:in `require'
    from /Users/adam/rubydev/future_computers/config/application.rb:7:in `<top (required)>'
    from /Users/adam/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.2.1/lib/rails/commands.rb:53:in `require'
    from /Users/adam/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.2.1/lib/rails/commands.rb:53:in `block in <top (required)>'
    from /Users/adam/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.2.1/lib/rails/commands.rb:50:in `tap'
    from /Users/adam/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.2.1/lib/rails/commands.rb:50:in `<top (required)>'
    from script/rails:6:in `require'
    from script/rails:6:in `<main>'adam

I don't really know how to fix this, I've added the eventmachine gem into the Gemfile, but it didn't help...

Could you help me, please, how to fix it?

Thank you

Answer 1

In my case this fixed it:

• $ gem uninstall eventmachine
• at the prompt tell it to uninstall all versions (it tells you about dependencies)
• $ bundle install

I was reading through this https://github.com/eventmachine/eventmachine/issues/333. There were problems with eventmachine, so making sure I got the newest version seemed a good idea.

Answer 2

For me, compiling eventmachine from sources with tweaked config helped. Try:

Uninstall eventmachine if it's already installed:

gem uninstall eventmachine

Fetch eventmachine sources:

git clone https://github.com/eventmachine/eventmachine.git
cd eventmachine

Edit ext/extconf.rb and ext/fastfilereader/extconf.rb files by adding CONFIG['CXX'] = "g++" right after require 'mkmf'

Compile and install gem:

rake gem
gem install pkg/eventmachine-1.0.3.gem

Now eventmachine should work just fine :)