Error when trying to install app with mysql2 gem

问题

Im trying to install an open source rails 3.2.21 application that uses the mysql2 gem, but when i try and run the bundle commant I get the following error:

Fetching: mysql2-0.3.18.gem (100%)
Building native extensions.  This could take a while...
p
ERROR:  Error installing mysql2:
    ERROR: Failed to build gem native extension.

    /Users/my_username/.rvm/rubies/ruby-2.1.2/bin/ruby -r ./siteconf20150614-72129-orqsb7.rb 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
-----
Using mysql_config at /usr/local/bin/mysql_config
-----
checking for mysql.h... yes
checking for errmsg.h... yes
checking for mysqld_error.h... yes
-----
Don't 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/5.6.25/lib
-----
creating Makefile

make "DESTDIR=" clean

make "DESTDIR="
compiling client.c
compiling infile.c
compiling mysql2_ext.c
compiling result.c
linking shared-object mysql2/mysql2.bundle
ld: warning: directory not found for option '-L/Users/travis/.sm/pkg/active/lib'
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/my_username/.rvm/rubies/ruby-2.1.2/lib/ruby/gems/2.1.0/gems/mysql2-0.3.18 for inspection.
Results logged to /Users/my_username/.rvm/rubies/ruby-2.1.2/lib/ruby/gems/2.1.0/extensions/x86

I tried uninstalling every version of mysql I installed via homebrew and reinstalling them, like so:

brew uninstall --force mysql && brew install mysql

Then running:

sudo gem install mysql2

As suggested by a number of similar questions asked on here, but it still results in the same error as above.

Please could someone offer guidance on how to get this up and running?

回答1:

The error log says:

ld: library not found for -lssl

So, you need to install libssl:

brew install openssl

Hope it helps.

回答2:

For anybody still experiencing the issue:

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:

The solution for me was to install the Xcode Command Line Tools.

I had recently updated Xcode through the Mac App Store, and every time I do that, I've found that I have to reinstall the Command Line Tools again.

xcode-select --install

回答4:

Try this:

gem install mysql2 -v '0.5.2' -- --with-ldflags=-L/usr/local/opt/openssl/lib --with-cppflags=-I/usr/local/opt/openssl/include

(Update version as appropriate)

回答5:

Based on the solution here

brew install openssl

export LIBRARY_PATH=$LIBRARY_PATH:/usr/local/opt/openssl/lib/

solved the problem.

回答6:

Thanks @mudasobwa for pointing me in the right direction. It turns out the error was caused by an unlinked openssl file, so running:

brew reinstall openssl && brew link openssl --force 

Solved the problem. I found the solution here: OpenSSL, RVM, Brew, conflicting error

回答7:

sudo installer -pkg /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg -target /

From here: https://gorails.com/setup/osx/10.14-mojave

回答8:

The combination of commands solved it me. I am on Mojave.

brew reinstall openssl && brew link openssl --force

and then

gem install mysql2 -v '0.4.10' -- --with-ldflags=-L/usr/local/opt/openssl/lib --with-cppflags=-I/usr/local/opt/openssl/include

回答9:

I found that I had to use --with-opt-dir=/usr/local/opt.

Specifically, I added the following to my ~/.bundle/config file:

BUNDLE_BUILD__MYSQL2: "--with-opt-dir=/usr/local/opt"

来源：https://stackoverflow.com/questions/30834421/error-when-trying-to-install-app-with-mysql2-gem