kernels.yml

# This job builds test kernels and uploads them to the `assets` dummy release.
#
# It works by looking at the KERNELS file in the repository and checks it
# against all the already-uploaded kernels.

name: Kernels

on:
  workflow_dispatch:        # Manual trigger
  push:                     # Automatic trigger
    branches: [ "master" ]

concurrency:
  # Ensure only a single instance of this job is run at any time
  group: ${{ github.ref }}

permissions:
  contents: write

jobs:
  build-upload:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v3

    - name: Calculate needed kernels
      id: calculate
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
      run: |
        existing=$(gh release view assets --json assets --jq '.[][].name')

        # Begin multiline output parameter
        echo "NEEDED_KERNELS<<MULTILINE_EOF" >> "$GITHUB_OUTPUT"

        echo "$existing" | python3 -c '
        import sys

        # Calculate kernels that have already been uploaded
        existing = {line.strip() for line in sys.stdin}
        with open("./KERNELS", "r") as f:
            lines = {line.strip() for line in f if line.strip()}

        # Print to stdout kernel we need to build and upload
        for line in lines:
            version = line.strip()
            name = f"linux-{version}.tar.zst"
            if name not in existing:
                print(line)
        ' | tee -a "$GITHUB_OUTPUT"

        # End multiline output parameter
        echo "MULTILINE_EOF" >> "$GITHUB_OUTPUT"

    - name: Build needed kernels
      run: |
        while IFS= read -r version; do
            echo "Building: ${version}"
            ./build.sh "$version"
        done <<< "${{ steps.calculate.outputs.NEEDED_KERNELS }}"

    - name: Upload freshly built kernels
      env:
        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
      run: |
        for kernel in linux-*; do
          gh release upload assets "$kernel"
        done