CI/CD Actions for compiling apps on Github Actions using processing android

Currently, there aren’t any existing GitHub Actions to automatically build desktop and mobile apps from Processing .pde code. I’ve been working on setting one up, as you can see from the build.yml file attached. However, I’m running into an issue determining the correct folder that Processing considers its "sketchbook" directory. This is important because the Android libraries need to be placed there for the project to build successfully.

I would really appreciate your guidance in fixing this. Having a working GitHub Actions setup for Processing sketches, games, and apps could benefit the entire Processing community by enabling automated builds. Not to mention many app stores for libre software won't accept software without reproducible builds using CI/CD actions.

Link to my test project: https://github.com/ronynn/spark

name: Build Processing Android APK

on:
  push:
    tags:
      - "alpha"
      - "beta"
      - "release*"

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout repository
        uses: actions/checkout@v3

      - name: Install OpenJDK
        run: |
          sudo apt-get update && sudo apt-get install -y openjdk-17-jdk

      - name: Install Processing CLI
        run: |
          wget https://github.com/processing/processing4/releases/download/processing-1297-4.3.4/processing-4.3.4-linux-x64.tgz -O processing.tgz
          tar -xzf processing.tgz
          sudo mv processing-4.3.4 /opt/processing

      - name: Debug Repository Structure
        run: ls -R $GITHUB_WORKSPACE

      - name: Install Android SDK
        run: |
          sudo apt-get install -y unzip
          wget https://dl.google.com/android/repository/commandlinetools-linux-11076708_latest.zip -O sdk-tools.zip
          mkdir -p $HOME/android-sdk/cmdline-tools
          unzip sdk-tools.zip -d $HOME/android-sdk/cmdline-tools
          mv $HOME/android-sdk/cmdline-tools/cmdline-tools $HOME/android-sdk/cmdline-tools/latest
          echo "ANDROID_HOME=$HOME/android-sdk" >> $GITHUB_ENV
          echo "PATH=$ANDROID_HOME/cmdline-tools/latest/bin:$ANDROID_HOME/platform-tools:$PATH" >> $GITHUB_ENV
          yes | $HOME/android-sdk/cmdline-tools/latest/bin/sdkmanager --sdk_root=$HOME/android-sdk "platform-tools" "build-tools;34.0.0" "platforms;android-34"
          yes | $HOME/android-sdk/cmdline-tools/latest/bin/sdkmanager --licenses

      - name: Install Processing Android Mode and Setup Sketchbook
        run: |
          # Create a custom sketchbook folder with both modes and libraries directories.
          mkdir -p $HOME/sketchbook/modes
          mkdir -p $HOME/sketchbook/libraries
          wget https://github.com/processing/processing-android/releases/download/latest/AndroidMode.zip -O AndroidMode.zip
          unzip AndroidMode.zip -d $HOME/sketchbook/modes/
          # If the Android Mode package contains libraries (commonly in modes/AndroidMode/libraries),
          # copy them into the sketchbook libraries folder so Processing can find them.
          if [ -d "$HOME/sketchbook/modes/AndroidMode/libraries" ]; then
            cp -r $HOME/sketchbook/modes/AndroidMode/libraries/* $HOME/sketchbook/libraries/
          fi
          echo "PROCESSING_SKETCHBOOK=$HOME/sketchbook" >> $GITHUB_ENV
          echo "Sketchbook structure:" 
          ls -R $HOME/sketchbook

      - name: Generate Android Project
        run: |
          /opt/processing/processing-java \
            --sketch=$GITHUB_WORKSPACE/spark \
            --output=$GITHUB_WORKSPACE/build \
            --force --export --variant android \
            --sketchbook=$HOME/sketchbook

      - name: Build APK (Ant)
        run: |
          cd $GITHUB_WORKSPACE/build/android
          ant debug
          ant release

      - name: Upload Debug APK as Artifact
        uses: actions/upload-artifact@v4
        with:
          name: Processing-Android-APK-Debug
          path: build/android/bin/app-debug.apk

      - name: Upload Unsigned APK as Artifact
        uses: actions/upload-artifact@v4
        with:
          name: Processing-Android-APK-Unsigned
          path: build/android/bin/app-release-unsigned.apk

      - name: Create GitHub Release (Only for Release Tags)
        if: startsWith(github.ref, 'refs/tags/release')
        uses: softprops/action-gh-release@v1
        with:
          tag_name: ${{ github.ref_name }}
          name: Processing APK - ${{ github.ref_name }}
          draft: false
          prerelease: false
          files: |
            build/android/bin/app-debug.apk
            build/android/bin/app-release-unsigned.apk
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

Start with the build.yml workflow in the issue and the processing-java invocation, especially the --sketchbook path and Android Mode setup. Verify which sketchbook directory and library layout Processing expects, then test the workflow against the linked spark project. Done means a GitHub Actions run can reproducibly generate and build the Android APK artifacts.