mysql2版本0.5.2安装失败

Question

我试图在运行OSX10.14.1并使用Rails 5.2.2的MacBook上安装mysql2 (版本0.5.2)。我已经使用gem安装mysql2安装了它，但是没有成功，但是它在我的gem文件中是这样的：

gem 'mysql2'

当我尝试安装gem mysql2时，会得到以下错误：

Fetching mysql2 0.5.2
Installing mysql2 0.5.2 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

current directory:         /Users/lawrence/.rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/mysql2-    0.5.2/ext/mysql2
/Users/lawrence/.rbenv/versions/2.5.3/bin/ruby -r ./siteconf20181213-11829-    1fv4si0.rb extconf.rb
checking for rb_absint_size()... yes
checking for rb_absint_singlebit_p()... yes
checking for rb_wait_for_single_fd()... yes
-----
Using mysql_config at /usr/local/bin/mysql_config
-----
checking for mysql.h... yes
checking for errmsg.h... yes
checking for SSL_MODE_DISABLED in mysql.h... yes
checking for SSL_MODE_PREFERRED in mysql.h... yes
checking for SSL_MODE_REQUIRED in mysql.h... yes
checking for SSL_MODE_VERIFY_CA in mysql.h... yes
checking for SSL_MODE_VERIFY_IDENTITY in mysql.h... yes
checking for MYSQL.net.vio in mysql.h... yes
checking for MYSQL.net.pvio in mysql.h... no
checking for MYSQL_ENABLE_CLEARTEXT_PLUGIN in mysql.h... yes
checking for SERVER_QUERY_NO_GOOD_INDEX_USED in mysql.h... yes
checking for SERVER_QUERY_NO_INDEX_USED in mysql.h... yes
checking for SERVER_QUERY_WAS_SLOW in mysql.h... yes
checking for MYSQL_OPTION_MULTI_STATEMENTS_ON in mysql.h... yes
checking for MYSQL_OPTION_MULTI_STATEMENTS_OFF in mysql.h... yes
checking for my_bool in mysql.h... no
-----
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/8.0.12/lib
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creating Makefile

current directory:     /Users/lawrence/.rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/mysql2-    0.5.2/ext/mysql2
make "DESTDIR=" clean

current directory:     /Users/lawrence/.rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/mysql2-0.5.2/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/lawrence/.rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/gems/mysql2-0.5.2 for inspection.
Results logged to     /Users/lawrence/.rbenv/versions/2.5.3/lib/ruby/gems/2.5.0/extensions/x86_64-    darwin-18/2.5.0-static/mysql2-0.5.2/gem_make.out
An error occurred while installing mysql2 (0.5.2), and Bundler cannot continue.
Make sure that `gem install mysql2 -v '0.5.2' --source 'https://rubygems.org/'` succeeds before bundling.

In Gemfile: mysql2

我怎样才能解决这个问题？

Answer 1

我找到了答案

Mojave更改了编译C扩展所需的头文件的位置。您可能需要运行以下命令来安装pg、mysql2、nokogiri或其他需要C扩展的宝石：

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

按照下面的链接，找出更多。

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

Answer 2

ld: library not found for -lssl可能是罪魁祸首。

试试brew install openssl。此外，请查看this post以获得更多信息。

编辑:对于未来的用户来说，这对我来说是一个类似的问题。确保将-v更改为所需的任何版本。我在rails 4.2.x中使用了0.4.10，Rails 5.x将使用0.5.x。

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