build-iso.yaml

name: Build Remastered ISO

on:
  pull_request:
  workflow_dispatch:
    inputs:
      iso_image_url:
        description: 'URL of the Debian netinstall ISO'
        type: string
        required: false

jobs:
  desktop-debian-stable:
    runs-on: ubuntu-latest
    environment: build-iso-image

    env:
      ISO_IMAGE_URL: ${{ github.event.inputs.iso_image_url || vars.ISO_IMAGE_URL }}
      REMASTERED_ISO_IMAGE: preseed-debian-netinst-amd64.iso
      ORIGINAL_ISO_IMAGE: debian-netinst.iso
      PRESEED_FILE_TEMPLATE: preseed.txt.template
      PRESEED_FILE: preseed.txt
      ISO_FILES_DIR: isofiles

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          sparse-checkout: |
            ${{ env.PRESEED_FILE_TEMPLATE }}
          sparse-checkout-cone-mode: false

      - name: Install dependencies
        run: |
          sudo apt-get update
          sudo apt-get install -y cpio isolinux xorriso

      - name: Download Debian netinstall ISO
        run: |
          curl -L ${{ env.ISO_IMAGE_URL }} -o ${{ env.ORIGINAL_ISO_IMAGE }}

      - name: Extract ISO files
        run: |
          mkdir ${{ env.ISO_FILES_DIR }}
          sudo xorriso -osirrox on -indev ${{ env.ORIGINAL_ISO_IMAGE }} -extract / /media/debian-netinst
          cp -rT /media/debian-netinst ${{ env.ISO_FILES_DIR }}

      - name: Generate preseed file
        run: |
          sed -e "s/\${ROOT_PASSWORD}/${{ secrets.ROOT_PASSWORD }}/g" \
              -e "s/\${USER_FULLNAME}/${{ vars.USER_FULLNAME }}/g" \
              -e "s/\${USERNAME}/${{ vars.USERNAME }}/g" \
              -e "s/\${USER_PASSWORD}/${{ secrets.USER_PASSWORD }}/g" \
              ${{ env.PRESEED_FILE_TEMPLATE }} > ${{ env.PRESEED_FILE }}

      - name: Modify initrd and add preseed file
        env:
          INSTALL_DIR: ${{ env.ISO_FILES_DIR }}/install.amd
        run: |
          chmod +w -R ${{ env.INSTALL_DIR }}
          gunzip ${{ env.INSTALL_DIR }}/initrd.gz
          echo ${{ env.PRESEED_FILE }} | cpio -H newc -o -A -F ${{ env.INSTALL_DIR }}/initrd
          gzip ${{ env.INSTALL_DIR }}/initrd
          chmod -w -R ${{ env.INSTALL_DIR }}

      - name: Regenerate md5sum.txt
        working-directory: ${{ env.ISO_FILES_DIR }}
        env:
          CI: ""
        run: |
          chmod +w md5sum.txt
          find -follow -type f ! -name md5sum.txt -print0 | xargs -0 md5sum > md5sum.txt
          chmod -w md5sum.txt

      - name: Create new bootable ISO
        env:
          ORIGINAL_ISO: ${{ env.ORIGINAL_ISO_IMAGE }}
          NEW_FILES: ${{ env.ISO_FILES_DIR }}
          NEW_ISO: ${{ env.REMASTERED_ISO_IMAGE }}
          MBR_TEMPLATE: /usr/lib/ISOLINUX/isohdpfx.bin
        run: |
          # Extract MBR template file to disk
          dd if=${{ env.ORIGINAL_ISO }} bs=1 count=432 of=${{ env.MBR_TEMPLATE }}

          # Create the new ISO image
          xorriso \
            -as mkisofs \
            -r -V 'Debian amd64' \
            -o ${{ env.NEW_ISO }} \
            -J -joliet-long -cache-inodes \
            -isohybrid-mbr ${{ env.MBR_TEMPLATE }} \
            -b isolinux/isolinux.bin \
            -c isolinux/boot.cat \
            -boot-load-size 4 -boot-info-table -no-emul-boot \
            -eltorito-alt-boot \
            -e boot/grub/efi.img \
            -no-emul-boot -isohybrid-gpt-basdat -isohybrid-apm-hfsplus \
            ${{ env.NEW_FILES }}

      - name: Upload ISO artifact
        uses: actions/upload-artifact@v4
        with:
          name: remastered-iso
          path: ${{ env.REMASTERED_ISO_IMAGE }}
          if-no-files-found: warn
          retention-days: 7