Ruby Gem - LoadError

Question

Ruby newbie here trying to figure out how to use a Gem and thus far the experience is not that great.

After installing mysql2 via gem I tried to use it in a simple file.

require 'mysql2'

#client = Mysql2::Client.new(:host => "localhost", :username => "username")

Though when I run this I get:

Parse.rb:1:in `require': no such file to load -- mysql2 (LoadError)
 from Parse.rb:1

Yet my gem list contains mysql2:

Tanner-Smiths-MacBook-Pro:Humans_vs_Zombies_Parse tanner$ gem list

*** LOCAL GEMS ***

abstract (1.0.0)
actionmailer (3.0.1, 2.3.5, 1.3.6)
actionpack (3.0.1, 2.3.5, 1.13.6)
actionwebservice (1.2.6)
activemodel (3.0.1)
activerecord (3.0.1, 2.3.5, 1.15.6)
activeresource (3.0.1, 2.3.5)
activesupport (3.0.1, 2.3.5, 1.4.4)
acts_as_ferret (0.4.3)
arel (2.0.2)
builder (2.1.2)
capistrano (2.5.19, 2.5.2)
cgi_multipart_eof_fix (2.5.0)
daemons (1.1.0, 1.0.10)
dnssd (1.4, 0.6.0)
erubis (2.6.6)
fastthread (1.0.7, 1.0.1)
fcgi (0.8.8, 0.8.7)
ferret (0.11.6)
gem_plugin (0.2.3)
highline (1.6.1, 1.5.0)
hpricot (0.8.3, 0.6.164)
i18n (0.4.2)
jk-ferret (0.11.8.2)
libxml-ruby (1.1.4, 1.1.2)
mail (2.2.9)
mime-types (1.16)
mongrel (1.1.5)
mysql2 (0.2.6)
needle (1.3.0)
net-scp (1.0.4, 1.0.1)
net-sftp (2.0.5, 2.0.1, 1.1.1)
net-ssh (2.0.23, 2.0.4, 1.1.4)
net-ssh-gateway (1.0.1, 1.0.0)
polyglot (0.3.1)
rack (1.2.1, 1.0.1)
rack-mount (0.6.13)
rack-test (0.5.6)
rails (2.3.5, 1.2.6)
railties (3.0.1)
rake (0.8.7, 0.8.3)
RedCloth (4.2.3, 4.1.1)
ruby-openid (2.1.8, 2.1.2)
ruby-yadis (0.3.4)
rubynode (0.1.5)
sqlite3-ruby (1.3.2, 1.2.4)
termios (0.9.4)
thor (0.14.4)
treetop (1.4.8)
tzinfo (0.3.23)
xmpp4r (0.5, 0.4)

Results of "ruby env":

RubyGems Environment:
  - RUBYGEMS VERSION: 1.3.5
  - RUBY VERSION: 1.8.7 (2009-06-12 patchlevel 174) [universal-darwin10.0]
  - INSTALLATION DIRECTORY: /Library/Ruby/Gems/1.8
  - RUBY EXECUTABLE: /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
  - EXECUTABLE DIRECTORY: /usr/bin
  - RUBYGEMS PLATFORMS:
    - ruby
    - universal-darwin-10
  - GEM PATHS:
     - /Library/Ruby/Gems/1.8
     - /Users/tanner/.gem/ruby/1.8
     - /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => false
     - :bulk_threshold => 1000
  - REMOTE SOURCES:
     - http://gems.rubyforge.org/

What am I doing wrong here? I can't figure it out.

Thanks

-Tanner

Answer 1

Try:

require 'rubygems'
require 'mysql2'

Answer 2

As you probably noticed, you have multiple versions of ruby installed. I strongly recommand you using RVM to manage multiple ruby versions.

It is a wild guess but if you aren't using the command line to run your application and using a tools such as TextMate you might need set a shell variable "TM_RUBY" to point to the ruby version with the installed rubygems (1.8.7 (2009-06-12 patchlevel 174)).

You can try:

/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/irb

to get to the irb version with the rubygems installed and than try:

require 'rubygems'
require 'mysql2'

If thats work and you are happy with that you could either update you symbolic links in /usr/bin/ruby, /usr/bin/irb, /usr/bin/gem to point to the older version of ruby or once again install RVM and make your life much easier.

Answer 3

To get more info, start up irb and run:

require 'rubygems'
gem 'mysql2'  #=> does this cause an error?
$:.grep /mysql2/  #=> if no error from previous line, please post what this shows

Also at the terminal prompt, run "gem contents mysql2". Do you see paths ending with the following?

lib/mysql2/error.rb
lib/mysql2/mysql2.bundle
lib/mysql2/client.rb
lib/mysql2/result.rb
lib/mysql2.rb