Spack Build-Cache Action

A GitHub Actions composite action to:

1. Install your project (and dependencies) via Spack
2. Push the resulting binary buildcache to a remote OCI registry mirror

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Features

• Checks out your repository (including submodules)
• Sets up Spack via spack/setup-spack
• Clones your custom Spack package recipes repo
• Adds it as a Spack repository
• Installs the specified Spack environment variant
• Pushes the buildcache to a specified OCI mirror

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Usage

Add this step to your workflow:

jobs:
  build-cache:
    runs-on: ubuntu-24.04
    permissions:
      packages: write

    steps:
      - name: Build & Push Spack Buildcache
        uses: numpex/spack-buildcache-action@v1
        with:
          env-variant: default
          mirror: my-org/my-spack-mirror
          # Optional inputs shown with their defaults:
          # repo-packages: numpex/spack.numpex
          # repo-packages-path: spack.numpex
          # spack-path: _spack
          # base-image: ubuntu:24.04

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Inputs

Input	Description	Required	Default
env-variant	Spack environment variant to install (e.g. default, omp, etc.)	✅	—
mirror	Name of the OCI mirror (e.g. my-org/my-spack-mirror)	✅	—
repo-packages	GitHub repo with your Spack package recipes		numpex/spack.numpex
repo-packages-path	Local directory to clone the Spack packages repo		spack.numpex
spack-path	Local install path for the Spack checkout		_spack
base-image	Base Docker image passed to spack buildcache push --base-image		ubuntu:24.04

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Example Workflow

name: CI

on:
  push:
    tags:
      - 'v*'

jobs:
  build-cache:
    runs-on: ubuntu-24.04
    permissions:
      packages: write

    steps:
      - name: Build & publish Spack cache
        uses: numpex/spack-buildcache-action@v1
        with:
          env-variant: default
          mirror: numpex/spack-buildcache

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Test Workflow Example

Here’s a sample workflow you can use within your Spack Build-Cache Action repository to test the action locally:

name: Test Spack Build-Cache Action

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

jobs:
  smoke:
    runs-on: ubuntu-24.04
    permissions:
      contents: read
      packages: write

    steps:
      # 1) Check out this action’s code
      - name: Checkout action
        uses: actions/checkout@v4

      # 2) Run our composite action locally
      - name: Run Spack Build-Cache
        uses: ./
        with:
          env-variant: default
          repo-packages: numpex/spack.numpex
          repo-packages-path: spack.numpex
          mirror: numpex-buildcache

      # 3) Verify installed specs
      - name: List installed specs
        run: |
          . _spack/share/spack/setup-env.sh
          spack find -lv

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License

BSD-3 License