问题
I'm setting up my development environment in the new macOS Sierra .
First of all, I installed Rbenv, Ruby (2.3.1), Homebrew and so the latest version of MySQL (5.7.15).
$ brew install mysql
$ mysql.server start
Ok, MySQL was initialized. Time to install the mysql2 gem...
$ gem install mysql2 -- --with-mysql-config=/usr/local/Cellar/mysql/5.7.15/bin/mysql_config
But it didn't work. 😞
Building native extensions with: '--with-mysql-config=/usr/local/Cellar/mysql/5.7.15/bin/mysql_config'
This could take a while...
ERROR: Error installing mysql2:
ERROR: Failed to build gem native extension.
current directory: /Users/macuser/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.4/ext/mysql2
/Users/macuser/.rbenv/versions/2.3.1/bin/ruby -r ./siteconf20160921-16853-x1boio.rb extconf.rb --with-mysql-config=/usr/local/Cellar/mysql/5.7.15/bin/mysql_config
checking for ruby/thread.h... yes
checking for rb_thread_call_without_gvl() in ruby/thread.h... yes
checking for rb_thread_blocking_region()... no
checking for rb_wait_for_single_fd()... yes
checking for rb_hash_dup()... yes
checking for rb_intern3()... yes
-----
Using mysql_config at /usr/local/Cellar/mysql/5.7.15/bin/mysql_config
-----
checking for mysql.h... yes
checking for errmsg.h... yes
checking for mysqld_error.h... yes
-----
Dont know how to set rpath on your system, if MySQL libraries are not in path mysql2 may not load
-----
-----
Setting libpath to /usr/local/Cellar/mysql/5.7.15/lib
-----
creating Makefile
To see why this extension failed to compile, please check the mkmf.log which can be found here:
/Users/macuser/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/extensions/x86_64-darwin-16/2.3.0-static/mysql2-0.4.4/mkmf.log
current directory: /Users/macuser/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.4/ext/mysql2
make "DESTDIR=" clean
current directory: /Users/macuser/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.4/ext/mysql2
make "DESTDIR="
compiling client.c
compiling infile.c
compiling mysql2_ext.c
compiling result.c
compiling statement.c
linking shared-object mysql2/mysql2.bundle
ld: library not found for -lssl
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [mysql2.bundle] Error 1
make failed, exit code 2
Gem files will remain installed in /Users/macuser/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.4 for inspection.
Results logged to /Users/macuser/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/extensions/x86_64-darwin-16/2.3.0-static/mysql2-0.4.4/gem_make.out
回答1:
I just had the same problem, tried all of the solutions listed above, then commenced to bang my head against they keyboard for a couple of hours.
I then thought to try and install/reinstall the Xcode Command Line Tools:
xcode-select --install
Once I did that the mysql2 gem installed w/ no problems. I hope that does the trick!
回答2:
When you install openssl via brew, you should get the following message:
Apple has deprecated use of OpenSSL in favor of its own TLS and crypto libraries
Generally there are no consequences of this for you. If you build your own software and it requires this formula, you'll need to add to your build variables:
LDFLAGS: -L/usr/local/opt/openssl/lib
CPPFLAGS: -I/usr/local/opt/openssl/include
PKG_CONFIG_PATH: /usr/local/opt/openssl/lib/pkgconfig
You can set these build flags (for the local application) by running the following:
bundle config --local build.mysql2 "--with-ldflags=-L/usr/local/opt/openssl/lib --with-cppflags=-I/usr/local/opt/openssl/include"
This worked for me.
See bundler's documentation for more information.
回答3:
I am here to share my fix, since the other answers didn't work.
For my environment, I need MySQL 5.6 so I had to use:
brew install mysql56 instead of brew install mysql
Bundle installing the mysql2 gem kept failing, until:
brew link mysql56
I also ran afterwards:
mysql.server start
The last step might be unnecessary, but just in case.
回答4:
Lots of great answers, I was able to combine them into this:
gem install mysql2 --source 'https://rubygems.org/' -- --with-ldflags=-L/usr/local/opt/openssl/lib --with-cppflags=-I/usr/local/opt/openssl/include
because I was not comfortable with bundle config
回答5:
Almost the same scenario as @Caio Tarifa, Ruby 2.3.3, mysql 5.6 and mysql2. Tried on couple of solutions above and finally make it work with @kylekeesling's approach.
First, tried on solution 1 by @spickermann:
brew reinstall openssl && brew link openssl --force
Nothing happened, same error shown.
Second, tried on solution by @Alessandro Berardi:
bundle config --local build.mysql2 "--with-ldflags=-L/usr/local/opt/openssl/lib --with-cppflags=-I/usr/local/opt/openssl/include"
This got different but more errors since it overwrite gem extension's config so all gem extension installation failed.
Finally, tried on @kylekeesling solution:
xcode-select --install
It fix mysql gem issue as well as nikogiri. Since I already intall Xcode, in my case it's reinstall the Xcode Command Line Tools.
回答6:
Try installing xcode-select --install
回答7:
So I ran into this similar issue and for me it turned out to be a wrong ruby version and incompatible MySQL version. I use ruby 2.3 on most of my projects but inherited a 2.1 project. Changing to rvm to use 2.1 got me a little further.
Then I found this: https://github.com/brianmario/mysql2/issues/603 that said you had to use mysql2 gem version greater than 0.3.17 with MySQL version 5.7
Updated gem to 0.3.17 and it fired right up. Hope this helps someone.
回答8:
I have a problem like this. Hope this could be useful .
brew install mysql@5.6
brew link mysql@5.6 --force
bundle install
this answer help me !
回答9:
With Mac OS 10.15 Catalina when I tried Alessandro's fix the gem and extensions could be installed correctly but bundle install failed. What worked was just:
bundle config --local build.mysql2 "--with-ldflags=-L/usr/local/opt/openssl/lib"
without the cppflags part.
回答10:
If none of the above works .. like in my case, doing this solved the issue
brew install openssl
FYI: i am using MacOS Catalina
回答11:
First, you should try 2 answer in here If you installed openssl but it still don't work. You should try to o refresh gems reference. A got the same issue and it worked for me.
gem source -r https://rubygems.org/
gem source -a https://rubygems.org/
来源：https://stackoverflow.com/questions/39617761/cant-install-mysql2-gem-on-macos-sierra