Lustre Dev Tools

Features

• Built-in development server.

• Automatic detection and support for TailwindCSS.

• Bundle and minify Lustre applications.

• Distribute reusable Web Components for use outside of Gleam and Lustre.

Philosophy

Lustre’s dev tools are designed to make the experience as simple as possible for folks unfamiliar with frontend development or are exhausted at the state of JavaScript tooling. That means being opinionated about the tools we support and the commands we provide.

If you find yourself needing more configuration or control over your build process, you might be outgrowing what Lustre’s dev tools have set out to provide! We’d love to hear from those users too, though, so please open an issue or reach out on Discord if you think something is missing.

For more advanced users, we recommend using vite and the vite-gleam package.

Installation

Lustre’s dev tools are published on Hex! You can add them as a dev dependency to your Gleam projects from the command line:

Note: currently one of lustre_dev_tools’ dependencies is not compatible with the most recent version of gleam_json, making it impossible to install. To fix this, add gleam_json = "1.0.1" as a dependency in your gleam.toml file.

gleam add lustre_dev_tools --dev

The --dev flag is important to make sure the dev tools are not included in your application’s build!

Note: The included development server uses the erlang package fs as a file watcher. For Linux uses, you need to have inotify-tools installed on your system. Both Linux and MacOS users must also have a C compiler.

To run any of the commands provided by the dev tools, you should run the lustre/dev module using Gleam’s run command:

gleam run -m lustre/dev build app

Commands

You can run gleam run -m lustre/dev -- --help to see a list of all the available commands. Each command also has its own help text that lists the available flags and options. Here’s a brief overview of the commands provided by Lustre’s dev tools:

• lustre/dev add - Commands for adding external binaries to your project. These are run and managed by Lustre, and while not typically intended to be run manually, they can be found inside build/.lustre/bin.

  • lustre/dev add esbuild - Download a platform-appropriate version of the esbuild binary. Lustre uses this to bundle applications and act as a development server, and will automatically download the binary if either the build or start commands are run.

  • lustre/dev add tailwind - Download a platform-appropriate version of the Tailwind binary. Lustre will automatically use this to compile your styles if it detects a tailwind.config.js in your project but will not download it automatically. Be sure to add the following to your root level index.html

    <link rel="stylesheet" type="text/css" href="/priv/static/my_app.css" />

• lustre/dev build - Commands to build different kinds of Lustre application. These commands go beyond just running gleam build and handle features like bundling, minification, and integration with other build tools.

  • lustre/dev build app - Build and bundle an entire Lustre application. The generated JavaScript module calls your app’s main function on page load and can be included in any Web page without Gleam or Lustre being present.

  • lustre/dev build component - Build a Lustre component as a portable Web Component. The generated JavaScript module can be included in any Web page and used without Gleam or Lustre being present.

• lustre/dev start - Start a development server for your Lustre project. This command will compile your application and serve it on a local server. If your application’s main function returns a compatible App, this will generate the necessary code to start it. Otherwise, your main function will be used as the entry point.

Support

Lustre is mostly built by just me, Hayleigh, around two jobs. If you’d like to support my work, you can sponsor me on GitHub.

Contributions are also very welcome! If you’ve spotted a bug, or would like to suggest a feature, please open an issue or a pull request.