backport.yml

---
name: Backport changes
on:
  pull_request:
    types:
      - closed
    branches:
      - main
jobs:
  get-labels:
    if: github.event.pull_request.merged == true
    runs-on: ubuntu-latest
    outputs:
      branches: ${{ steps.get-labels.outputs.branches }}
      user: ${{ steps.get-labels.outputs.user }}
      valid: ${{ steps.get-labels.outputs.valid }}
    steps:
      - name: Determine branches to cherry-pick to
        id: get-labels
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        run: |
          # concat labels into comman-separated string, e.g. "bug,backport to all versions,remediation"
          PR_LABELS="${{ join(github.event.pull_request.labels.*.name, ',') }}"
          if [[ -z "$PR_LABELS" ]]; then
            echo "valid=false" >> $GITHUB_OUTPUT
            exit 0
          else
            echo "valid=true" >> $GITHUB_OUTPUT
          fi

          BRANCHES=""
          if [[ $PR_LABELS =~ "backport to all versions" ]]; then
            # fetch all branches with 'v/' prefix from the GitHub API
            RAW_RESPONSE=$(gh api --paginate --jq '.[].name' /repos/${{ github.repository }}/branches)
            ALL_BRANCHES=$(echo "$RAW_RESPONSE" | grep '^v/')

            # Prepare the BRANCHES variable, remove trailing comma and newline
            BRANCHES=$(echo "$ALL_BRANCHES" | tr '\n' ',')
            BRANCHES=${BRANCHES%,}  # Removing the trailing comma and newline
          else
            BRANCH_NAMES=$(echo "$PR_LABELS" | grep -o 'backport to v/[0-9]\+\.[0-9]\+' | sed -e 's/backport to //')
            BRANCHES=$(echo "$BRANCH_NAMES" | tr '\n' ',')
            BRANCHES=${BRANCHES::-1}  # Removing the trailing comma
          fi

          # Convert BRANCHES into a valid JSON array
          BRANCHES_ARRAY=$(echo "$BRANCHES" | tr ', ' '\n\n' | sed 's/^/"/;s/$/"/' | tr '\n' ',' | sed 's/,$//')
          BRANCHES_ARRAY="[$BRANCHES_ARRAY]"

          echo "branches=$BRANCHES_ARRAY" >> $GITHUB_OUTPUT
          echo "user=${{ github.actor }}" >> $GITHUB_OUTPUT
  backport:
    needs: get-labels
    if: needs.get-labels.outputs.branches != '' && needs.get-labels.outputs.valid == 'true'
    strategy:
      matrix:
        branch: ${{fromJson(needs.get-labels.outputs.branches)}}
    runs-on: ubuntu-latest
    permissions:
      id-token: write
      contents: read
    steps:
      - uses: aws-actions/configure-aws-credentials@v4
        with:
          aws-region: ${{ vars.RP_AWS_CRED_REGION }}
          role-to-assume: arn:aws:iam::${{ secrets.RP_AWS_CRED_ACCOUNT_ID }}:role/${{ vars.RP_AWS_CRED_BASE_ROLE_NAME }}${{ github.event.repository.name }}
      - uses: aws-actions/aws-secretsmanager-get-secrets@v2
        with:
          secret-ids: |
            ,sdlc/prod/github/actions_bot_token
          parse-json-secrets: true
      # Checkout the specified branch from redpanda repository.
      - name: Checkout redpanda repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0
          repository: redpanda-data/docs
          token: ${{ env.ACTIONS_BOT_TOKEN }}
      - name: Set up git config
        run: |
          echo "Setting up git config..."
          git config user.name "vbotbuildovich"
          git config user.email "vbotbuildovich@users.noreply.github.com"
      - name: Checkout maintenance branch and cherry-pick
        run: |
          echo "Fetching latest changes..."
          git fetch
          # Check if the branch exists
          BRANCH_CHECK=$(git ls-remote --heads origin ${{ matrix.branch }})
          if [[ -z "$BRANCH_CHECK" ]]; then
              echo "Branch ${{ matrix.branch }} does not exist. Skipping."
              exit 0
          fi

          echo "Checking out branch: ${{ matrix.branch }}..."
          git checkout ${{ matrix.branch }} || (echo "Failed to checkout branch: ${{ matrix.branch }}." && exit 1)

          echo "Cherry-picking changes..."
          # Attempt cherry-pick and capture any errors
          if ! git cherry-pick -x $GITHUB_SHA; then
            echo "Cherry-pick had conflicts for branch ${{ matrix.branch }}. Creating GitHub issue for manual intervention."

            # Create a GitHub issue
            issue_title="Manual backport required for ${{ matrix.branch }}"
            issue_body="A conflict occurred while backporting commit $GITHUB_SHA to branch ${{ matrix.branch }}. Manual intervention is required.\
            \nTo manually apply the change, you must cherry-pick it locally and fix the conflicts:\
            \n\`\`\`bash\
            \n git fetch origin\
            \n git checkout ${{ matrix.branch }}\
            \n git pull origin ${{ matrix.branch }}\
            \n git cherry-pick $GITHUB_SHA\
            \n # Resolve any merge conflicts here, then commit the changes\
            \n git push origin ${{ matrix.branch }}\
            \n\`\`\`\
            \nIf you no longer want to backport the change to this version, close this issue."

            response=$(curl -sS -w "%{http_code}" -X POST \
            -H "Authorization: token ${{ env.ACTIONS_BOT_TOKEN }}" \
            -H "Accept: application/vnd.github.v3+json" \
            https://api.github.com/repos/${{ github.repository }}/issues \
            -d "{ \"title\": \"$issue_title\", \"body\": \"$issue_body\", \"assignees\": [\"${{ needs.get-labels.outputs.user }}\"] }")

            status_code=$(echo "$response" | tail -n 1)

            if [[ $status_code -lt 200 || $status_code -gt 299 ]]; then
              echo "Failed to create GitHub issue. HTTP status code: $status_code"
              echo "$response"
              exit 1
            fi
            json_response=$(echo "$response" | head -n -1)
            issue_url=$(echo "$json_response" | jq '.html_url')

            git cherry-pick --abort
            echo "Failed to cherry-pick. Manual intervention might be needed. See the created issue: $issue_url"
          else
            echo "Pushing changes to branch: ${{ matrix.branch }}..."
            git push
          fi