Question

Hey Guys
I’m trying to get the Railscasts source code from github. when I’m running the bundle install, I got this error :

installing mysql2 (0.2.6) with native extensions /usr/local/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:529:in `rescue in block in build_extensions': ERROR: Failed to build gem native extension. (Gem::Installer::ExtensionBuildError)

        /usr/local/bin/ruby extconf.rb 
checking for rb_thread_blocking_region()... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lm... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lz... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lsocket... no
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lnsl... no
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lmygcc... no
checking for mysql_query() in -lmysqlclient... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Provided configuration options:
    --with-opt-dir
    --without-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/usr/local/bin/ruby
    --with-mysql-config
    --without-mysql-config
    --with-mysql-dir
    --without-mysql-dir
    --with-mysql-include
    --without-mysql-include=${mysql-dir}/include
    --with-mysql-lib
    --without-mysql-lib=${mysql-dir}/lib
    --with-mysqlclientlib
    --without-mysqlclientlib
    --with-mlib
    --without-mlib
    --with-mysqlclientlib
    --without-mysqlclientlib
    --with-zlib
    --without-zlib
    --with-mysqlclientlib
    --without-mysqlclientlib
    --with-socketlib
    --without-socketlib
    --with-mysqlclientlib
    --without-mysqlclientlib
    --with-nsllib
    --without-nsllib
    --with-mysqlclientlib
    --without-mysqlclientlib
    --with-mygcclib
    --without-mygcclib
    --with-mysqlclientlib
    --without-mysqlclientlib


Gem files will remain installed in /Users/yozloy/.bundler/tmp/61472/gems/mysql2-0.2.6 for inspection.
Results logged to /Users/yozloy/.bundler/tmp/61472/gems/mysql2-0.2.6/ext/mysql2/gem_make.out
    from /usr/local/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:507:in `block in build_extensions'
    from /usr/local/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:482:in `each'
    from /usr/local/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:482:in `build_extensions'
    from /usr/local/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:156:in `install'
    from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.10/lib/bundler/source.rb:96:in `install'
    from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.10/lib/bundler/installer.rb:55:in `block in run'
    from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.10/lib/bundler/spec_set.rb:12:in `block in each'
    from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.10/lib/bundler/spec_set.rb:12:in `each'
    from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.10/lib/bundler/spec_set.rb:12:in `each'
    from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.10/lib/bundler/installer.rb:44:in `run'
    from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.10/lib/bundler/installer.rb:8:in `install'
    from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.10/lib/bundler/cli.rb:226:in `install'
    from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.10/lib/bundler/vendor/thor/task.rb:22:in `run'
    from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.10/lib/bundler/vendor/thor/invocation.rb:118:in `invoke_task'
    from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.10/lib/bundler/vendor/thor.rb:246:in `dispatch'
    from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.10/lib/bundler/vendor/thor/base.rb:389:in `start'
    from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.0.10/bin/bundle:13:in `<top (required)>'
    from /usr/local/bin/bundle:19:in `load'
    from /usr/local/bin/bundle:19:in `<main>'

Answer 1

sudo apt-get install --assume-yes mysql-server-5.1 mysql-client-5.1 libmysqlclient-dev

That should be all you need for the mysql2 gem.