feat: support polling for watching files

CHANGELOG.md

@@ -1,7 +1,9 @@
 
 ## Unreleased
 
-* Correctly handle paths with embedded spaces. [#184](https://github.com/rails/tailwindcss-rails/issues/184)
+* Correctly handle paths with embedded spaces. [#184](https://github.com/rails/tailwindcss-rails/issues/184) by [@flavorjones](https://github.com/flavorjones)
+* The `build` and `watch` tasks accept a `debug` argument to generate unminified assets: `rails tailwindcss:build[debug]` or `rails tailwindcss:watch[debug]`. [#198](https://github.com/rails/tailwindcss-rails/pull/198) by [@flavorjones](https://github.com/flavorjones)
+* The `watch` task accepts a `poll` argument to use polling instead of file system events: `rails tailwindcss:watch[poll]`. [#199](https://github.com/rails/tailwindcss-rails/pull/199) by [@flavorjones](https://github.com/flavorjones)
 
 
 ## v2.0.12 / 2022-08-10

README.md

@@ -2,45 +2,71 @@
 
 [Tailwind CSS](https://tailwindcss.com) is a utility-first CSS framework packed with classes like flex, pt-4, text-center and rotate-90 that can be composed to build any design, directly in your markup.
 
+## Installation
+
+With Rails 7 you can generate a new application preconfigured with Tailwind by using `--css tailwind`. If you're adding Tailwind later, you need to:
+
+1. Run `./bin/bundle add tailwindcss-rails`
+2. Run `./bin/rails tailwindcss:install`
+
 This gem wraps [the standalone executable version](https://tailwindcss.com/blog/standalone-cli) of the Tailwind CSS v3 framework. These executables are platform specific, so there are actually separate underlying gems per platform, but the correct gem will automatically be picked for your platform. Supported platforms are Linux x64, macOS arm64, macOS x64, and Windows x64. (Note that due to this setup, you must install the actual gems – you can't pin your gem to the github repo.)
 
+
+## Developing with Tailwindcss
+
+### Configuration
+
 You can customize the Tailwind build through the `config/tailwind.config.js` file, just like you would if Tailwind was running in a traditional node installation. All the first-party plugins are supported.
 
 The installer will create your Tailwind input file in `app/assets/stylesheets/application.tailwind.css`. This is where you import the plugins you want to use, and where you can setup your custom `@apply` rules. When you run `rails tailwindcss:build`, this input file will be used to generate the output in `app/assets/builds/tailwind.css`. That's the output CSS that you'll include in your app (the installer automatically configures this, alongside the Inter font as well).
 
-If you need to use a custom input or output file, you can run `bundle exec tailwindcss` to access the platform-specific executable, and give it your own build options.
 
-When you're developing your application, you want to run Tailwind in watch mode, so changes are automatically reflected in the generated CSS output. You can do this either by running `rails tailwindcss:watch` as a separate process, or by running `./bin/dev` which uses [foreman](https://github.com/ddollar/foreman) to starts both the Tailwind watch process and the rails server in development mode. If you are running `rails tailwindcss:watch` as a process in a Docker container, set `tty: true` in `docker-compose.yml` for the appropriate container to keep the watch process running.
+### Building for production
 
+The `tailwindcss:build` is automatically attached to `assets:precompile`, so before the asset pipeline digests the files, the Tailwind output will be generated.
 
-## Installation
 
-With Rails 7 you can generate a new application preconfigured with Tailwind by using `--css tailwind`. If you're adding Tailwind later, you need to:
+### Building for testing
 
-1. Run `./bin/bundle add tailwindcss-rails`
-2. Run `./bin/rails tailwindcss:install`
+The `tailwindcss:build` is automatically attached to `test:prepare`, which runs before Rails tests. (Note that this currently only applies to rails `test:*` tasks (like `test:all` or `test:controllers`), not "rails test", as that doesn't load `test:prepare`).
 
 
-## Building in production
+### Update assets automatically
 
-The `tailwindcss:build` is automatically attached to `assets:precompile`, so before the asset pipeline digests the files, the Tailwind output will be generated.
+While you're developing your application, you want to run Tailwind in "watch" mode, so changes are automatically reflected in the generated CSS output. You can do this by:
 
-## Building for testing
+- running `rails tailwindcss:watch` as a separate process,
+- or by running `./bin/dev` which uses [foreman](https://github.com/ddollar/foreman) to start both the Tailwind watch process and the rails server in development mode.
 
-The `tailwindcss:build` is automatically attached to `test:prepare`, which runs before Rails tests. (Note that this currently only applies to rails `test:*` tasks (like `test:all` or `test:controllers`), not "rails test", as that doesn't load `test:prepare`).
+If you are running `rails tailwindcss:watch` as a process in a Docker container, set `tty: true` in `docker-compose.yml` for the appropriate container to keep the watch process running.
 
-## Conflict with sassc-rails
+If you are running `rails tailwindcss:watch` on a system that doesn't fully support file system events, pass a `poll` argument to the task to instruct tailwindcss to instead use polling: `rails tailwindcss:watch[poll]`. If you use `bin/dev` then you should modify your `Procfile.dev`.
 
-Tailwind uses modern CSS features that are not recognized by the `sassc-rails` extension that was included by default in the Gemfile for Rails 6. In order to avoid any errors like `SassC::SyntaxError`, you must remove that gem from your Gemfile.
 
-## Class names must be spelled out
+### Debugging with unminified assets
+
+If you want unminified assets, you can pass a `debug` argument to the rake task, i.e. `rails tailwindcss:build[debug]` or `rails tailwindcss:watch[debug]`.
+
+Note that you can combine task options, e.g. `rails tailwindcss:watch[debug,poll]`.
+
+
+### Custom inputs or outputs
+
+If you need to use a custom input or output file, you can run `bundle exec tailwindcss` to access the platform-specific executable, and give it your own build options.
 
-For Tailwind to work, your class names need to be spelled out. They can't be programmatically composed. So no "text-gray-#{grade}", only "text-gray-500".
 
 ## Troubleshooting
 
 Some common problems experienced by users ...
 
+### Conflict with sassc-rails
+
+Tailwind uses modern CSS features that are not recognized by the `sassc-rails` extension that was included by default in the Gemfile for Rails 6. In order to avoid any errors like `SassC::SyntaxError`, you must remove that gem from your Gemfile.
+
+### Class names must be spelled out
+
+For Tailwind to work, your class names need to be spelled out. They can't be programmatically composed. So no "text-gray-#{grade}", only "text-gray-500".
+
 ### ERROR: Cannot find the tailwindcss executable for <supported platform>
 
 Some users are reporting this error even when running on one of the supported native platforms:

lib/tailwindcss/commands.rb

@@ -55,18 +55,22 @@ def executable(
         exe_path
       end
 
-      def compile_command(**kwargs)
+      def compile_command(debug: false, **kwargs)
         [
           executable(**kwargs),
           "-i", Rails.root.join("app/assets/stylesheets/application.tailwind.css").to_s,
           "-o", Rails.root.join("app/assets/builds/tailwind.css").to_s,
           "-c", Rails.root.join("config/tailwind.config.js").to_s,
-          "--minify",
-        ]
+        ].tap do |command|
+          command << "--minify" unless debug
+        end
       end
 
-      def watch_command(**kwargs)
-        compile_command(**kwargs) << "-w"
+      def watch_command(poll: false, **kwargs)
+        compile_command(**kwargs).tap do |command|
+          command << "-w"
+          command << "-p" if poll
+        end
       end
     end
   end

lib/tasks/build.rake

@@ -1,14 +1,17 @@
 namespace :tailwindcss do
   desc "Build your Tailwind CSS"
-  task :build do
-    command = Tailwindcss::Commands.compile_command
+  task :build do |_, args|
+    debug = args.extras.include?("debug")
+    command = Tailwindcss::Commands.compile_command(debug: debug)
     puts command.inspect
     system(*command, exception: true)
   end
 
   desc "Watch and build your Tailwind CSS on file changes"
-  task :watch do
-    command = Tailwindcss::Commands.watch_command
+  task :watch do |_, args|
+    debug = args.extras.include?("debug")
+    poll = args.extras.include?("poll")
+    command = Tailwindcss::Commands.watch_command(debug: debug, poll: poll)
     puts command.inspect
     system(*command)
   end

test/lib/tailwindcss/commands_test.rb

@@ -48,6 +48,12 @@ def mock_exe_directory(platform)
         actual = Tailwindcss::Commands.compile_command(exe_path: dir)
         assert_kind_of(Array, actual)
         assert_equal(executable, actual.first)
+        assert_includes(actual, "--minify")
+
+        actual = Tailwindcss::Commands.compile_command(exe_path: dir, debug: true)
+        assert_kind_of(Array, actual)
+        assert_equal(executable, actual.first)
+        refute_includes(actual, "--minify")
       end
     end
   end
@@ -59,6 +65,22 @@ def mock_exe_directory(platform)
         assert_kind_of(Array, actual)
         assert_equal(executable, actual.first)
         assert_includes(actual, "-w")
+        refute_includes(actual, "-p")
+        assert_includes(actual, "--minify")
+
+        actual = Tailwindcss::Commands.watch_command(exe_path: dir, debug: true)
+        assert_kind_of(Array, actual)
+        assert_equal(executable, actual.first)
+        assert_includes(actual, "-w")
+        refute_includes(actual, "-p")
+        refute_includes(actual, "--minify")
+
+        actual = Tailwindcss::Commands.watch_command(exe_path: dir, poll: true)
+        assert_kind_of(Array, actual)
+        assert_equal(executable, actual.first)
+        assert_includes(actual, "-w")
+        assert_includes(actual, "-p")
+        assert_includes(actual, "--minify")
       end
     end
   end