Rails
Ubuntu
bundler
mysql2

Ubuntuでmysql2 gemが入らない。

More than 5 years have passed since last update.

MySQL向けのgem「mysql2」を含んだGemfileを使ってbundle installしようとしたときに出力されたエラーメッセージ。

Error
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

/home/user/.rbenv/versions/2.0.0-p247/bin/ruby extconf.rb 
checking for rb_thread_blocking_region()... yes
checking for rb_wait_for_single_fd()... 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... yes
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=/home/user/.rbenv/versions/2.0.0-p247/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}/
    --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 /home/user/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/mysql2-0.3.11 for inspection.
Results logged to /home/user/.rbenv/versions/2.0.0-p247/lib/ruby/gems/2.0.0/gems/mysql2-0.3.11/ext/mysql2/gem_make.out

An error occurred while installing mysql2 (0.3.11), and Bundler cannot continue.
Make sure that `gem install mysql2 -v '0.3.11'` succeeds before bundling.

MySQLのヘッダファイルが見当たらないので、インストールします。

Installation
$ sudo apt-get install libmysqld-dev 

これで、bundle installが通るようになりました。