TIL = Things, or Today I Learned

An experiment in Learning in Public.


Ruby - use MSYS2 to install Ruby dev packages to build native extensions on Windows

Aim: Use MSYS2 to install the development packages Ruby needs to build native extensions on Windows.

Why? because I found out that some Ruby gems must be build as native extensions. Without this setup, installing such gems never works.

Pre-requisites: Ruby is installed.

Background and Problem

After setting up my laptop according to https://github.com/juliusgb/dev-laptop-setup, I cloned my Jekyll site that's based on Simply Jekyll site, ran gem install bundler jekyll && bundle install, and was greeted with the error:

In Gemfile:
  jekyll-feed was resolved to 0.16.0, which depends on
    jekyll was resolved to 4.0.1, which depends on
      em-websocket was resolved to 0.5.3, which depends on
mingw32-make: *** [makefile:5: prep] Error 5

Manually installing the http_parser.rb gem with command gem install http_parser.rb --version 0.6.0 returned

Temporarily enhancing PATH for MSYS/MINGW...
Building native extensions. This could take a while...
ERROR:  Error installing http_parser.rb:
        ERROR: Failed to build gem native extension.

From stackoverflow, I found out that

The error indicates that Ruby needs to compile native (non-Ruby) code in order to install and use the http_parser gem. To compile native code on Windows you need to install Ruby with the DevKit package. —2018, https://stackoverflow.com/a/50929914

Why the DevKit? Because the RubyInstaller DevKit contains development packages required to compile with Ruby C-extensions.

But according to the DevKit documentation,

Stating with RubyInstaller-2.4 we’re no longer using our own DevKit compilation, but make use of MSYS2 for both building Ruby itself as well as building Ruby gems with C-extensions.

So I need do the following:

  • Make sure that MSYS2 is installed.
  • Install the development packages Ruby needs to needs build with C-extensions. Since ridk was installed during Ruby's installation, running ridk install 3 installs the relevant packages.


Use MSYS2 to install the development packages Ruby needs to build native extensions on Windows.

Using the Dev-laptop Setup repo

I setup my laptop using https://github.com/juliusgb/dev-laptop-setup. I added MSYS2 to it in a pull request, and re-ran packer build.

Using Chocolatey

Another option is to use Chocolatey - https://community.chocolatey.org/packages/msys2.

  • Open PowerShell as Administrator
  • If you don't have Ruby installed, run choco install ruby
  • Run choco install msys2 --params "/NoUpdate /InstallDir:C:\your\install\path"
  • Refresh the shell's environment variables with refreshenv
  • Use the RubyInstaller2 ridk to install only the development packages that Ruby needs build with C-extensions. Run ridk install 3
  • Check that MSYS was correctly installed by running ridk version. The output should show msys2 and the path to it.

      C:\Users\juliu>ridk version
        path: C:/opt/tools/Ruby/3.0.4/x64
        version: 3.0.4
        platform: x64-mingw32
        cc: gcc.exe (Rev10, Built by MSYS2 project) 11.2.0
        package_version: 3.0.4-1
        git_commit: 17502f9
        path: C:\opt\msys2
      cc: gcc (Rev3, Built by MSYS2 project) 12.1.0
      sh: GNU bash, Version 5.1.16(1)-release (x86_64-pc-msys)
      os: Microsoft Windows [Version 10.0.19044.1826]

Installing gems that are built as native extensions

Running gem install http_parser.rb --version 0.6.0 works without errors