feat: package tailwindcss binary executables with the gem

See rakelib/package.rake for details.

Author: flavorjones

.gitignore

@@ -12,4 +12,5 @@
 .byebug_history
 *.gem
 .idea/
-**/tmp/
+**/tmp/
+/exe/*/tailwindcss-*

bin/release

@@ -14,6 +14,9 @@ git commit -m "Bump version for $VERSION"
 git push
 git tag v$VERSION
 git push --tags
-gem build tailwindcss-rails.gemspec
-gem push "tailwindcss-rails-$VERSION.gem" --host https://rubygems.org
-rm "tailwindcss-rails-$VERSION.gem"
+
+rake package
+for gem in pkg/tailwindcss-rails-$VERSION*.gem ; do
+  gem push "$gem" --host https://rubygems.org
+  rm "$gem"
+done

exe/tailwindcss

@@ -0,0 +1,13 @@
+#! /usr/bin/env ruby
+# because rubygems shims assume a gem's executables are Ruby
+
+require "shellwords"
+
+platform = Gem::Platform.local.to_s
+exe_path = Dir.glob(File.join(__dir__, platform, "tailwindcss*"))
+
+if exe_path.empty?
+  raise "Cannot find the tailwindcss executable for #{platform} in #{__dir__}"
+end
+
+exec(Shellwords.join([exe_path, ARGV].flatten))

rakelib/package.rake

@@ -0,0 +1,116 @@
+# coding: utf-8
+#
+#  Rake tasks to manage native gem packages with binary executables from tailwindlabs/tailwindcss
+#
+#  TL;DR: run "rake package"
+#
+#  The native platform gems (defined by TAILWINDCSS_NATIVE_PLATFORMS below) will each contain two
+#  files in addition to what the vanilla ruby gem contains:
+#
+#     exe/
+#     ├── tailwindcss                             #  generic ruby script to find and run the binary
+#     └── <Gem::Platform architecture name>/
+#         └── tailwindcss-<platform extension>    #  the tailwindcss binary executable
+#
+#  The ruby script `exe/tailwindcss` is installed into the user's path, and it simply locates the
+#  binary and executes it. Note that this script is required because rubygems requires that
+#  executables declared in a gemspec must be Ruby scripts.
+#
+#  As a concrete example, an x86_64-linux system will see these files on disk after installing
+#  tailwindcss-rails-1.x.x-x86_64-linux.gem:
+#
+#     exe/
+#     ├── tailwindcss
+#     └── x86_64-linux/
+#         └── tailwindcss-linux-x64
+#
+#  So the full set of gem files created will be:
+#
+#  - pkg/tailwindcss-rails-1.0.0.gem
+#  - pkg/tailwindcss-rails-1.0.0-arm64-darwin.gem
+#  - pkg/tailwindcss-rails-1.0.0-x64-mingw32.gem
+#  - pkg/tailwindcss-rails-1.0.0-x86_64-darwin.gem
+#  - pkg/tailwindcss-rails-1.0.0-x86_64-linux.gem
+# 
+#  Note that in addition to the native gems, a vanilla "ruby" gem will also be created without
+#  either the `exe/tailwindcss` script or a binary executable present.
+#
+#
+#  New rake tasks created:
+#
+#  - rake gem:ruby           # Build the ruby gem
+#  - rake gem:arm64-darwin   # Build the arm64-darwin gem
+#  - rake gem:x64-mingw32    # Build the x64-mingw32 gem
+#  - rake gem:x86_64-darwin  # Build the x86_64-darwin gem
+#  - rake gem:x86_64-linux   # Build the x86_64-linux gem
+#  - rake download           # Download all tailwindcss binaries
+#
+#  Modified rake tasks:
+#
+#  - rake gem                # Build all the gem files
+#  - rake package            # Build all the gem files (same as `gem`)
+#  - rake repackage          # Force a rebuild of all the gem files
+#
+#  Note also that the binary executables will be lazily downloaded when needed, but you can
+#  explicitly download them with the `rake download` command.
+#
+require "rubygems/package_task"
+require "open-uri"
+
+TAILWINDCSS_VERSION = "v3.0.5" # string used to generate the download URL
+
+# rubygems platform name => upstream release filename
+TAILWINDCSS_NATIVE_PLATFORMS = {
+  "arm64-darwin" => "tailwindcss-macos-x64",
+  "x64-mingw32" => "tailwindcss-windows-x64.exe",
+  "x86_64-darwin" => "tailwindcss-macos-arm64",
+  "x86_64-linux" => "tailwindcss-linux-x64",
+}
+
+def tailwindcss_download_url(filename)
+  "https://github.com/tailwindlabs/tailwindcss/releases/download/#{TAILWINDCSS_VERSION}/#{filename}"
+end
+
+TAILWINDCSS_RAILS_GEMSPEC = Bundler.load_gemspec("tailwindcss-rails.gemspec")
+
+gem_path = Gem::PackageTask.new(TAILWINDCSS_RAILS_GEMSPEC).define
+desc "Build the ruby gem"
+task "gem:ruby" => [gem_path]
+
+exepaths = []
+TAILWINDCSS_NATIVE_PLATFORMS.each do |platform, filename|
+  TAILWINDCSS_RAILS_GEMSPEC.dup.tap do |gemspec|
+    exedir = File.join(gemspec.bindir, platform) # "exe/x86_64-linux"
+    exepath = File.join(exedir, filename) # "exe/x86_64-linux/tailwindcss-linux-x64"
+    exepaths << exepath
+
+    # modify a copy of the gemspec to include the native executable
+    gemspec.platform = platform
+    gemspec.executables << "tailwindcss"
+    gemspec.files << exepath
+
+    # create a package task
+    gem_path = Gem::PackageTask.new(gemspec).define
+    desc "Build the #{platform} gem"
+    task "gem:#{platform}" => [gem_path]
+
+    directory exedir
+    file exepath => [exedir] do
+      release_url = tailwindcss_download_url(filename)
+      warn "Downloading #{exepath} from #{release_url} ..."
+
+      # lazy, but fine for now.
+      URI.open(release_url) do |remote|
+        File.open(exepath, "wb") do |local|
+          local.write(remote.read)
+        end
+      end
+      FileUtils.chmod(0755, exepath, verbose: true)
+    end
+  end
+end
+
+desc "Download all tailwindcss binaries"
+task "download" => exepaths
+
+CLOBBER.add(exepaths.map { |p| File.dirname(p) })

tailwindcss-rails.gemspec

@@ -15,6 +15,7 @@ Gem::Specification.new do |spec|
   }
 
   spec.files = Dir["{app,lib}/**/*", "MIT-LICENSE", "Rakefile", "README.md"]
+  spec.bindir = "exe"
 
   spec.add_dependency "railties", ">= 6.0.0"
 end