gem install mysql2 不起作用

Question

我正在尝试安装 mysql2 gem 以用于学习 rails，但它不起作用。重新安装 mysql 或 ruby​​ 不起作用。使用 ARCHFLAGS 不起作用。我不能使用 apt-get libmysqlclient-dev 因为我的 Mac 没有 Ubuntu 服务器，而且无论如何这不会是 mysql 在安装自制软件时包含的依赖项（就像我所做的那样）？我也有最新的 Xcode (8.2.1)。这是完整的错误消息（用用户名代替实际用户名）：

Building native extensions.  This could take a while...
ERROR:  Error installing mysql2:
    ERROR: Failed to build gem native extension.

    current directory: /Users/username/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.5/ext/mysql2
/Users/username/.rbenv/versions/2.3.1/bin/ruby -r ./siteconf20170121-4906-1lcyftl.rb extconf.rb
checking for rb_absint_size()... yes
checking for rb_absint_singlebit_p()... yes
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
checking for rb_big_cmp()... yes
-----
Using mysql_config at /usr/local/bin/mysql_config
-----
checking for mysql.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 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/5.7.17/lib
-----
creating Makefile

To see why this extension failed to compile, please check the mkmf.log which can be found here:

  /Users/username/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/extensions/x86_64-darwin-16/2.3.0-static/mysql2-0.4.5/mkmf.log

current directory: /Users/username/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.5/ext/mysql2
make "DESTDIR=" clean

current directory: /Users/username/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.5/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/username/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/gems/mysql2-0.4.5 for inspection.
Results logged to /Users/username/.rbenv/versions/2.3.1/lib/ruby/gems/2.3.0/extensions/x86_64-darwin-16/2.3.0-static/mysql2-0.4.5/gem_make.out

我尝试安装 mysql2 的命令是：

gem install mysql2
sudo gem install mysql2 (if the error was permission denied.)
sudo gem install mysql2 -v '0.4.5' -- --with-mysql-config=/usr/local/Cellar/mysql/5.7.17/bin/mysql_config
ARCHFLAGS=-Wno-error=unused-command-line-argument-hard-error-in-future sudo gem install mysql2 -v '0.4.5'

不确定这些到底是什么意思，因为我是按照类似帖子的建议进行的。

请帮忙。谢谢！

Answer 1

您需要更改环境变量以包含以下内容（只需将 0.0.00 替换为所需版本的 MySQL2 gem：

gem install mysql2 -v '0.0.00' -- --with-ldflags=-L/usr/local/opt/openssl/lib --with-cppflags=-I/usr/local/opt/openssl/include

我还会检查您的 $PATH 并确保它包含 mysql gem，但上面的行应该可以工作（有一个非常相似的问题）