Automata Action

Update a Nix flake and land changes using Sapling. Supports submitting via ghstack or a regular GitHub Pull Request, with optional GPG commit signing.

What It Does

• Runs nix flake update --accept-flake-config
• Configures Sapling settings via nix run "<flake-url>" -- config
• Creates a CI commit via nix run "<flake-url>" -- ci
• Submits changes via:
  • ghstack submit when method: ghstack (default)
  • pr submit when method: pr
• Optionally imports a GPG private key and signs commits when sign-commits: 'true'

Prerequisites

This action expects Nix to be available on the runner. If you’re using GitHub-hosted runners, add these steps before this action:

- uses: DeterminateSystems/nix-installer-action@v20
- uses: DeterminateSystems/magic-nix-cache-action@v13

Inputs

• commit-message (default: Update Flake)
  • Commit message used by the ci step
• extra-args (default: "")
  • Extra arguments passed to nix run for all subcommands
• flake-url (default: nixpkgs#sapling)
  • Nix flake URL or path to use (e.g., a tool flake that provides config, ci, ghstack, and pr subcommands)
• github-token (default: ${{ github.token }})
  • GitHub token to authenticate ghstack or PR submission
• ghstack-username (default: github-actions)
  • Username used by Sapling’s ghstack integration
• gpg-private-key (default: "")
  • ASCII-armored GPG private key used to sign commits when sign-commits: 'true'
• gpg-passphrase (default: "")
  • Passphrase for the provided GPG private key (if needed)
• method (default: ghstack)
  • Publication method: ghstack or pr
• sign-commits (default: "false")
  • Set to "true" to enable GPG commit signing
• username (default: github-actions[bot])
  • Sapling ui.username to set locally before submitting

Quick Start (ghstack)

name: ci
on:
  push:
    branches: [main]
  pull_request:
    branches: [main]

jobs:
  automata:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - uses: shikanime-studio/setup-nix@v1

      - name: Update flake and land via ghstack
        uses: shikanime-studio/automata-action@v1
        with:
          commit-message: "Update flake and CI"
          flake-url: nixpkgs#sapling # or your own tool flake
          method: ghstack # default
          ghstack-username: github-actions
          username: github-actions[bot]

Quick Start (PR)

name: ci
on:
  workflow_dispatch:

jobs:
  automata:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - uses: shikanime-studio/setup-nix@v1

      - name: Update flake and open PR
        uses: shikanime-studio/automata-action@v1
        with:
          commit-message: "Update flake and CI"
          method: pr
          github-token: ${{ secrets.GITHUB_TOKEN }}
          username: github-actions[bot]

Optional: GPG Commit Signing

Provide a private key and enable signing:

- name: Update flake with signed commits
  uses: shikanime-studio/automata-action@v1
  with:
    sign-commits: "true"
    gpg-private-key: ${{ secrets.CI_GPG_PRIVATE_KEY }}
    gpg-passphrase: ${{ secrets.CI_GPG_PASSPHRASE }}