Project workflow using just

Getting Started

The justfile provides a streamlined interface for executing common project-specific tasks. To install just, you can use the command cargo install just or cargo binstall just. Alternatively, refer to the official installation instructions for your specific system.

Once installed, navigate to the project directory and run just commands as needed. For instance, the following commands will configure a default cmake-build-debug directory and build the project.

just build

To load a JS script during componentization and serve its output using Wasmtime, run:

just serve <filename>.js

To build and run integration tests run:

just test

To build and run Web Platform Tests run:

just wpt-setup # prepare WPT hosts
just wpt-test # run all tests
just wpt-test console/console-log-symbol.any.js # run specific test

To view a complete list of available recipes, run:

just --list

note

By default, the CMake configuration step is skipped if the build directory already exists. However, this can sometimes cause issues if the existing build directory was configured for a different target. For instance:

  • Running just build creates a build directory for the default target,
  • Running just wpt-build afterward may fail because the WPT target hasn’t been configured in the existing build directory.

To resolve this, you can force cmake to reconfigure the build directory by adding the reconfigure=true parameter. For example:

just reconfigure=true wpt-build

Customizing build

The default build mode is debug, which automatically configures the build directory to cmake-build-debug. You can switch to a different build mode, such as release, by specifying the mode parameter. For example:

just mode=release build

This command will set the build mode to release, and the build directory will automatically change to cmake-build-release.

If you want to override the default build directory, you can use the builddir parameter.

just builddir=mybuilddir mode=release build

This command configures CMake to use mybuilddir as the build directory and sets the build mode to release.

Starting the WPT Server

After running just wpt-setup as described above, you can also start a Web Platform Tests (WPT) server with:

just wpt-server

After starting the server, tests can be run interactively with a basic web interface running at http://127.0.0.1:7879/. Tests can be filtered by providing prefixes or exact names of subsets or specific tests.

Some examples:

  • Running all of StarlingMonkey’s WPT tests: http://127.0.0.1:7879/
  • Running all console tests: http://127.0.0.1:7879/console
  • Running a specific test: http://127.0.0.1:7879/console/console-log-symbol.any.js
curl http://127.0.0.1:7676/console/console-log-symbol.any.js