pebble.nix

Tools for building Pebble apps on Nix systems

Quickstart

Recommended: Install Cachix and use the pebble cache. Using Cachix is highly recommended, as building some required derivations (qemu-pebble, the ARM toolchain) locally can take a long time. Cachix provides prebuilt, binary backages so you don't have to do the building.

On non-NixOS systems:

nix-env -i cachix

On NixOS, add cachix to environment.systemPackages in your configuration.

Finally, to use the pebble.nix cache (you might need to run this command with sudo if your user isn't a trusted user in the Nix daemon):

cachix use pebble

After setting up Cachix, reboot the system. This is required to restart the Nix daemon so that it uses the new binary cache.

Development Shell

A development shell provides you with a shell containing the pebble tool and the Pebble emulator. To set it up in your project, create a shell.nix file with the following content in the root of your project:

(import
  (builtins.fetchTarball https://github.com/Sorixelle/pebble.nix/archive/master.tar.gz)
).pebbleEnv { }

Then, run nix-shell to open up a shell with all the tools for Pebble development.

Build for App Store

pebble.nix can build your watchapp or watchface, and package it in a bundle ready for deployment to the Rebble App Store. Create a default.nix file in the root of your project with the following content, and change the properties for your project:

(import
  (builtins.fetchTarball https://github.com/Sorixelle/pebble.nix/archive/master.tar.gz)
).buildPebbleApp {
  name = "App Name";
  src = ./.;
  type = "watchface";

  description = ''
    Your app description here.
  '';

  releaseNotes = ''
    Initial release.
  '';

  screenshots = {
    aplite = [ "assets/screenshots/aplite/screenshot.png" ];
    basalt = [ "assets/screenshots/basalt/screenshot.png" ];
    chalk = [ "assets/screenshots/chalk/screenshot.png" ];
    diorite = [ "assets/screenshots/diorite/screenshot.png" ];
  };
}

To build the bundle, run nix-build. The bundle will be output to result/appstore-bundle.tar.gz.

Flake Support

pebble.nix can be consumed as a flake, if you're using flakes in your project. You can use it with a flake.nix similar to the following:

{
  inputs.pebble.url = github:Sorixelle/pebble.nix;

  outputs = { self, pebble }: {
    devShell.${system} = pebble.pebbleEnv.${system} { };

    defaultPackage.${system} = pebble.buildPebbleApp.${system} { ... };
  };
}

Pinning

Using builtins.fetchTarball only caches a tarball for an hour by default. If you don't want to have to redownload pebble.nix every hour, you can pin to a specific commit.

builtins.fetchTarball {
  # Get the desired commit hash at https://github.com/Sorixelle/pebble.nix/commits
  url = https://github.com/Sorixelle/pebble.nix/archive/<commitHash>.tar.gz;
  # Get the hash by running "nix-prefetch-url --unpack <url>" on the tarball url
  sha256 = "<tarballHash>";
}

This is unnecessary if you're using flakes - flakes pin other flakes automatically.

Usage

Development shells

Development shells can be configured by specifying the following arguments to pebbleEnv:

devServerIP: The default development server IP. You can find this in the Pebble app.
emulatorTarget: The default target to start the Pebble emulator for.
cloudPebble: Whether to connect via a CloudPebble connection. Requires logging into Rebble via pebble login.
nativeBuildInputs: Any extra tools to use during development.

App Store Builds

buildPebbleApp requires a few specific attributes to create the metadata YAML file the Rebble App Store uses to create your app's page.

name: The name of your app.
type: The type of app. Must be either watchapp or watchface.
description: A description of your app.
releaseNotes: The release notes for this version of your app.
category: The category of your app. Only needed for watchapps. The valid values are:
- Daily
- Tools & Utilities
- Notifications
- Remotes
- Health & Fitness
- Games
banner: Path to a 720x320 image that will be displayed as the banner for your app. Optional for watchfaces.
smallIcon: Path to a 48x48 icon for your app. Optional for watchfaces.
largeIcon: Path to a 144x144 icon for your app. Optional for watchfaces.
homepage: A URL to the homepage for your app. Optional.
sourceUrl: A URL to the source code of your app. Optional.
screenshots: An attribute set containing screenshots of your app on Pebble watches. Each attribute contains a list of paths to screenshots. At least 1 screenshot in total must be provided. The following attributes are valid:
- aplite: Screenshots for the aplite platform (Pebble, Pebble Steel)
- basalt: Screenshots for the basalt platform (Pebble Time, Pebble Time Steel)
- chalk: Screenshots for the chalk platform (Pebble Time Round)
- diorite: Screenshots for the diorite platform (Pebble 2, Pebble 2 HR)
- all: Screenshots to be used for all platforms.

Other options relating to the build process:

src: Path to the project root. Usually ./. (the same folder your Nix expression is in).
nativeBuildInputs: Any extra tools/dependencies to be used at build time.