Configuring gems in eclipse

Question

I'm trying to work on a vagrant / chef project in eclipse. I'm fairly new to both technologies and a little rusty with ruby. I've installed rdt and have a ruby project with the code in.

However, eclipse doesn't seem to understand that gems are required. Is there a way to get ruby gems and eclipse to play nicely together. I thought that I could add gems as libraries but that doesn't seem to work.

Answer 1

I was having a very similar problem of getting Eclipse to recognize my installed gems. I was using rvm, with the default pointing to ruby 2.1.0. The ruby code that I was debugging had a single require 'mail' at the top. When running or debugging the script, the console displayed an error:

/Users/username/.rvm/rubies/ruby-2.1.0/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:54:in `require': cannot load such file -- mail (LoadError)
     from /Users/username/.rvm/rubies/ruby-2.1.0/lib/ruby/site_ruby/2.1.0/rubygems/core_ext/kernel_require.rb:54:in `require'
`<main>'

Eclipse had the correct ruby configured in its Preferences > Ruby > Interpreters: /Users/username/.rvm/rubies/ruby-2.1.0/bin/ruby

I knew the mail gem was installed for that ruby, outside of Eclipse:

$ gem which mail
/Users/username/.rvm/gems/ruby-2.1.0/gems/mail-2.6.3/lib/mail.rb

I tried @Don Kirkby's suggestion of adding -rubygems as an Interpreter argument in Debug Configurations, but it still wasn't working.

What DID get it working, oddly enough, was to add the GEM_HOME and GEM_PATH variables to the Environment section of the Debug Configurations.

I found the correct values (set by rvm, I presume) by echoing them in the terminal, outside of Eclipse:

$ echo $GEM_HOME
/Users/username/.rvm/gems/ruby-2.1.0
$ echo $GEM_PATH
/Users/username/.rvm/gems/ruby-2.1.0:/Users/username/.rvm/gems/ruby-2.1.0@global

Adding those two as environment variables in Debug Configurations > Environment tab did get debugging working in Eclipse, using the Ruby Built-In Debugger as the debug Engine in Preferences. Incidentally, I tried using 'Fast Ruby Debugger (ruby-debug)' engine, but got this error:

dyld: lazy symbol binding failed: Symbol not found: _rb_vm_get_sourceline
  Referenced from: /Users/username/.rvm/gems/ruby-2.1.0/extensions/x86_64-darwin-12/2.1.0-static/debugger-1.6.8/ruby_debug.bundle
  Expected in: flat namespace

dyld: Symbol not found: _rb_vm_get_sourceline
  Referenced from: /Users/username/.rvm/gems/ruby-2.1.0/extensions/x86_64-darwin-12/2.1.0-static/debugger-1.6.8/ruby_debug.bundle
  Expected in: flat namespace

Sidenote: Trying to hunt down a fix to the Symbol not found error for the Fast Ruby Debugger engine led me to this thread: Debugging in ruby 1.9 , which seems to imply that neither ruby-debug nor debugger gem is appropriate to use with ruby 2.0+, and instead recommended the byebug gem. But since I don't see a way to use byebug with Eclipse, I just ended up using the Ruby Built-In Debugger engine with the debugger and ruby-debug-ide gems:

$ gem install debugger
Successfully installed debugger-1.6.8
$ gem install ruby-debug-ide
Successfully installed ruby-debug-ide-0.4.26

which I got from this post: https://endocode.com/blog/2012/09/03/debugging-ruby-1-9-3-applications-in-eclipse/

Hopefully this is helpful to somebody who's trying to get Ruby 1.9/2.0+ debugging working with Eclipse.