mysql2 gem fails on bundle install, despite installing using `gem install...` command - ruby-on-rails

Question

Here is the log from my bundle install
Fetching mysql2 0.5.2
Installing mysql2 0.5.2 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
...
...
...
Cannot find mysql_config at /usr/local/opt/mysql#5.6/bin/mysql_config
--with-ldflags=-L/usr/local/opt/openssl/lib
--with-cppflags=-I/usr/local/opt/openssl/include
-----
*** 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
--without-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/admin/.asdf/installs/ruby/2.6.3/bin/$(RUBY_BASE_NAME)
--with-mysql-dir
--without-mysql-dir
--with-mysql-include
--without-mysql-include=${mysql-dir}/include
--with-mysql-lib
--without-mysql-lib=${mysql-dir}/lib
--with-mysql-config
To see why this extension failed to compile, please check the mkmf.log which can be found
here:
/Users/admin/development/locari/vendor/bundle/ruby/2.6.0/extensions/x86_64-darwin-18/2.6.0-static/mysql2-0.5.2/mkmf.log
extconf failed, exit code 1
Gem files will remain installed in
/Users/admin/development/locari/vendor/bundle/ruby/2.6.0/gems/mysql2-0.5.2 for
inspection.
Results logged to
/Users/admin/development/locari/vendor/bundle/ruby/2.6.0/extensions/x86_64-darwin-18/2.6.0-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.
So I do what it says, and run sudo gem install mysql2 -v '0.5.2' --source
$ sudo gem install mysql2 -v '0.5.2' --source 'https://rubygems.org/'
Building native extensions. This could take a while...
Successfully installed mysql2-0.5.2
Parsing documentation for mysql2-0.5.2
Done installing documentation for mysql2 after 0 seconds
1 gem installed
And it installs fine! But when I run bundle install again, I get the same error. I've tried uninstalling, unlinking, and reinstalling mysql in brew.
What can I try next??

Answer 1

Run these commands first:
bundle config --local build.mysql2 "--with-cppflags=-I/usr/local/opt/openssl/include --with-ldflags=-L/usr/local/opt/openssl/lib"
Then run bundle install it works.

Answer 2

Installation on M1 macs
This method helped me on ruby v2.7.2 and macOS Big Sur 11.4.
Install dependencies
brew install mysql zstd openssl
Install the gem
gem install mysql2 -- --with-ldflags="-L $(brew --cellar zstd)/1.5.0/lib -L $(brew --prefix openssl)/lib" --with-ldlibs="-lzstd -lssl" --with-cppflags="-I $(brew --prefix openssl)/include"
As an alternative, you can modify bundler config:
bundle config --local build.mysql2 --with-ldflags="-L $(brew --cellar zstd)/1.5.0/lib -L $(brew --prefix openssl)/lib" --with-ldlibs="-lzstd -lssl" --with-cppflags="-I $(brew --prefix openssl)/include"
and run bundle install.

Answer 3

Use build options with bundler.
Try running this in your application directory:
bundle config --local build.mysql2 "--with-ldflags=-L/usr/local/opt/openssl/lib --with-cppflags=-I/usr/local/opt/openssl/include"
This sets it just for your application, which can be handy for checking into your repo if others need a similar configuration. But you can also make it a global configuration on your computer by replacing --local with --global and it will apply to all your bundle install commands on your User account.
Update
This actually didn't end up working for me but I'll leave it here because it should have worked. I basically just had to run:
gem install mysql2 -v '0.5.3' -- --with-ldflags=-L/usr/local/opt/openssl/lib --with-cppflags=-I/usr/local/opt/openssl/include
Instead of using bundler, even though setting this build config should have done this.