release.yml

# This GitHub workflow is triggered when a new tag is pushed.
# A release is then created from this tag.

name: Release

on:
  push:
    tags:
      - "v*.*.*"

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
      - name: Get pushed tag
        id: get_tag
        run: echo ::set-output name=TAG::${GITHUB_REF/refs\/tags\//}

      - uses: actions/checkout@v3

      - run: git archive --output=rules_docker-${{ steps.get_tag.outputs.TAG }}.tar.gz ${{ steps.get_tag.outputs.TAG }}

      - name: Get SHA256 of archive
        id: get_sha
        run: echo "::set-output name=sha::$(sha256sum rules_docker-${{ steps.get_tag.outputs.TAG }}.tar.gz | cut -f 1 -d ' ')"

      - name: Create Release
        uses: softprops/action-gh-release@v1
        with:
          body: |
            Copy the following into your WORKSPACE file to use rules_docker at release ${{ steps.get_tag.outputs.TAG }}
            ```
            http_archive(
                name = "io_bazel_rules_docker",
                sha256 = "${{ steps.get_sha.outputs.sha }}",
                urls = ["https://github.com/${{ github.repository_owner }}/${{ github.event.repository.name }}/releases/download/${{ steps.get_tag.outputs.TAG }}/rules_docker-${{ steps.get_tag.outputs.TAG }}.tar.gz"],
            )
            ```
          generate_release_notes: true
          files: rules_docker-${{ steps.get_tag.outputs.TAG }}.tar.gz