错误：无法构建 gem 本机扩展（rails 3.2.3 上的 mysql2）

Question

I'm trying to install the mysql2 gem with Rails 3.2.3 and it's failing:

★  bundle install
Fetching gem metadata from https://rubygems.org/.........
Using rake (0.9.2.2) 
Using i18n (0.6.0) 
Using multi_json (1.2.0) 
Using activesupport (3.2.3) 
Using builder (3.0.0) 
Using activemodel (3.2.3) 
Using erubis (2.7.0) 
Using journey (1.0.3) 
Using rack (1.4.1) 
Using rack-cache (1.2) 
Using rack-test (0.6.1) 
Using hike (1.2.1) 
Using tilt (1.3.3) 
Using sprockets (2.1.2) 
Using actionpack (3.2.3) 
Using mime-types (1.18) 
Using polyglot (0.3.3) 
Using treetop (1.4.10) 
Using mail (2.4.4) 
Using actionmailer (3.2.3) 
Using arel (3.0.2) 
Using tzinfo (0.3.32) 
Using activerecord (3.2.3) 
Using activeresource (3.2.3) 
Using bundler (1.1.3) 
Using coffee-script-source (1.2.0) 
Using execjs (1.3.0) 
Using coffee-script (2.2.0) 
Using rack-ssl (1.3.2) 
Using json (1.6.6) 
Using rdoc (3.12) 
Using thor (0.14.6) 
Using railties (3.2.3) 
Using coffee-rails (3.2.2) 
Using jquery-rails (2.0.2) 
Installing mysql2 (0.3.11) with native extensions 
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

        /Users/rarneson/.rvm/rubies/ruby-1.9.3-p125/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... 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
    --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=/Users/rarneson/.rvm/rubies/ruby-1.9.3-p125/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/rarneson/.rvm/gems/ruby-1.9.3-p125/gems/mysql2-0.3.11 for inspection.
Results logged to /Users/rarneson/.rvm/gems/ruby-1.9.3-p125/gems/mysql2-0.3.11/ext/mysql2/gem_make.out
An error occured while installing mysql2 (0.3.11), and Bundler cannot continue.
Make sure that `gem install mysql2 -v '0.3.11'` succeeds before bundling.

I'm running bundle install and this is in my Gemfile:

gem 'mysql2', '~> 0.3.11' 

I've currently got MySQL running through MAMP. I'm not sure if this is a bad idea and I should run a vanilla MySQl but it seems my current problem is just getting the gem installed. I've seen quite a few of these problems here on stackoverflow but all seem a bit different or have really complicated solutions. Is there something I'm missing? Something simple? Something stupid? I can provide additional info from the out file if necessary. I've read that some people use SQLite for dev and test then MySQL in prod but that sounds like a pretty horrible idea.

Answer 1

From https://github.com/brianmario/mysql2/issues/8

just copied this in the console

sudo apt-get install mysql-client libmysqlclient-dev

and worked!!

Answer 2

I used Homebrew for Mac to install mysql:

brew install mysql

Then I used a gem command to install the mysql2 gem:

sudo gem install mysql2

Answer 3

This is mostly due to lack of mysql headers, Try to install mysql developer (mysql-devel) packages

Normally this error comes when 'libmysqlclient-dev' package is missing

• if you are on linux try this link
• if you are on windows this url might help you

Answer 4

I just ran into the same problem, using OS X Sierra and MAMP and Rails 5. I successfully installed the gem via

gem install mysql2 -- --with-mysql-config=/Applications/MAMP/Library/bin/mysql_config

After that, bundle install worked just fine.

Answer 5

I ended up just installing a fresh copy of MySQL and not using MAMP and that did the trick. Also had to be sure to install the 64-bit version, not 32-bit.

Answer 6

You can follow this thread Errors Installing mysql2 gem via the Bundler which explains the solution for Centos and this problem will be fixed, if you tweak the commands w.r.t your OS and you can be able to successfully install the mysql2 gem.

Answer 7

Just add MAMP mysql to PATH, then you can run bundle install as per normal.

$ /Applications/MAMP/Library/bin/mysql --host=localhost -uroot -proot

source: http://blog-en.mamp.info/2009/08/using-mysql-command-line-with-mamp.html

Answer 8

When I got this error, I was able to fix this by running:

gem install devtools