name: Release docker image

on:
  push:
    tags:
      - "*"

jobs:
  publish:
    name: Build and publish docker image
    runs-on: ubuntu-latest
    env:
      DOCKER_BUILDTAGS: "include_oss include_gcs"
      CGO_ENABLED: 1
      GO111MODULE: "auto"
      GOPATH: ${{ github.workspace }}
      GOOS: linux
      COMMIT_RANGE: ${{ github.event_name == 'pull_request' && format('{0}..{1}',github.event.pull_request.base.sha, github.event.pull_request.head.sha) || format('{0}..{1}', github.event.before, github.event.after) }}

    steps:
      - name: Get git tag
        id: get_git_tag
        run: echo ::set-output name=git_tag::${GITHUB_REF#refs/tags/}

      - name: Verify git tag
        env:
          GIT_TAG: ${{ steps.get_git_tag.outputs.git_tag }}
        # NOTE: this is a simple Regexp, following the current versioning scheme
        # In ideal world we should use this monstrosity:
        # https://semver.org/#is-there-a-suggested-regular-expression-regex-to-check-a-semver-string
        run: |
          [[ ${GIT_TAG} =~ ^v[0-9]+.[0-9]+.[0-9]+ ]]

      - name: Check out source code
        if: ${{ success() }}
        uses: actions/checkout@v2
        with:
          ref: ${{ steps.get_git_tag.outputs.git_tag }}

      - name: Set image tag
        env:
          GIT_TAG: ${{ steps.get_git_tag.outputs.git_tag }}
        id: get_image_tag
        run: echo ::set-output name=docker_tag::${GIT_TAG}

      - name: Login to Docker Hub
        uses: docker/login-action@v1
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

      - name: Build and push
        if: ${{ success() }}
        uses: docker/build-push-action@v2
        with:
          context: .
          file: ./Dockerfile
          platforms: linux/amd64
          push: true
          tags: distribution/distribution:{{ steps.get_image_tag.outputs.docker_tag }}