gem install mysql2 でエラー
mysql2 が含まれている Gemfile を使って bundle install してるときにエラーが出ました。
$ bundle install --path vendor/bundle --without development test Gem files will remain installed in /home/hoge/fuga/vendor/bundle/ruby/2.1.0/gems/mysql2-0.3.15 for inspection. Results logged to /home/hoge/fuga/vendor/bundle/ruby/2.1.0/extensions/x86_64-linux/2.1.0-static/mysql2-0.3.15/gem_make.out An error occurred while installing mysql2 (0.3.15), and Bundler cannot continue. Make sure that `gem install mysql2 -v '0.3.15'` succeeds before bundling.
言われるがままに mysql2 を突っ込んでみたがエラー
$ gem install mysql2 -v '0.3.15' Building native extensions. This could take a while... ERROR: Error installing mysql2: ERROR: Failed to build gem native extension. /home/hoge/.rbenv/versions/2.1.1/bin/ruby extconf.rb checking for ruby/thread.h... yes checking for rb_thread_call_without_gvl() in ruby/thread.h... yes checking for rb_thread_blocking_region()... yes checking for rb_wait_for_single_fd()... yes checking for rb_hash_dup()... yes checking for rb_intern3()... 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/hoge/.rbenv/versions/2.1.1/bin/ruby --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-mysql-config --without-mysql-config --with-mysql-dir --without-mysql-dir --with-mysql-include --without-mysql-include=${mysql-dir}/include --with-mysql-lib --with-mysql-lib --without-mysql-lib=${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 extconf failed, exit code 1 Gem files will remain installed in /home/hoge/.rbenv/versions/2.1.1/lib/ruby/gems/2.1.0/gems/mysql2-0.3.15 for inspection. Results logged to /home/hoge/.rbenv/versions/2.1.1/lib/ruby/gems/2.1.0/extensions/x86_64-linux/2.1.0-static/mysql2-0.3.15/gem_make.out
そもそも mysql.h がないらしい。
$ sudo apt-get install libmysqld-dev
ライブラリをインストールしてあげた後、再度試したら成功。