fix-github-actions-disk-space.md

Fix: GitHub Actions "No Space Left on Device" Error

Problem

GitHub Actions workflow failed with:

System.IO.IOException: No space left on device : '/home/runner/actions-runner/cached/_diag/Worker_20251110-081310-utc.log'

Root Cause

Kotlin Multiplatform project builds generate massive amounts of files:

• mpp-core: JS/JVM/Android artifacts (~500MB-1GB)
• mpp-ui: Compose Multiplatform with Android/Desktop targets (~2-3GB)
• mpp-server: Fat JAR with all dependencies (~100-200MB)
• Gradle caches: Dependencies and transforms (~2-5GB)
• node_modules (via Kotlin/JS): pnpm packages (~500MB-1GB)
• Android build outputs: APKs, intermediate files (~1-2GB)

Total: ~8-15GB per build, exhausting GitHub's default runner disk (~14GB free).

Solution Applied

1. Free Disk Space Before Each Job

Added jlumbroso/free-disk-space@main action to remove unused packages:

• ✅ Removes: Android SDK (on non-Android jobs), .NET, Haskell, Docker images, large packages
• 💾 Frees: ~14GB of disk space
• ⚠️ For build-android job: Keep Android SDK (android: false)

- name: Free Disk Space (Ubuntu)
  uses: jlumbroso/free-disk-space@main
  with:
    tool-cache: false
    android: true  # false for build-android job
    dotnet: true
    haskell: true
    large-packages: true
    docker-images: true
    swap-storage: true

2. Clean Build Artifacts After Each Build

Added cleanup steps after each Gradle build:

- name: Clean build cache to save space
  run: |
    ./gradlew :mpp-ui:clean
    rm -rf ~/.gradle/caches/modules-2/files-2.1
    rm -rf ~/.gradle/caches/transforms-*
    df -h

3. Disable Gradle Cache in CI

- name: Setup Gradle
  uses: gradle/actions/setup-gradle@v4
  with:
    cache-disabled: true  # Don't cache in CI (saves disk)

4. Use Gradle --no-daemon

Prevents Gradle daemon from consuming extra memory/disk:

./gradlew :mpp-core:assemble --no-daemon

Changes Made

Modified: .github/workflows/compose-release.yml

• ✅ Added disk cleanup to all 3 jobs: build-server, build-android, build-desktop
• ✅ Added --no-daemon to all Gradle commands
• ✅ Disabled Gradle cache (cache-disabled: true)
• ✅ Clean build artifacts after each build step

Expected Results

• Before: ~14GB free → Build fails at 70-80%
• After: ~28GB free (14GB initial + 14GB freed) → Build completes successfully

Disk Usage Breakdown (Estimated)

Initial free space:        14 GB
+ Cleanup (free-disk-space): +14 GB
= Total available:         28 GB

Build consumption:
- mpp-core:                 ~1 GB
- mpp-server:               ~2 GB
- mpp-ui (Android):         ~3 GB
- mpp-ui (Desktop x3):      ~6 GB (2GB per OS)
= Total needed:            ~12 GB

Final margin:              ~16 GB (safe)

Testing

To test the fix:

# Trigger workflow manually
git tag compose-test-$(date +%Y%m%d-%H%M%S)
git push origin --tags

# Or use workflow_dispatch
# Go to Actions → MPP Release → Run workflow

Alternative Solutions (Not Implemented)

Option A: Use Larger Runners

• GitHub-hosted larger runners (4-core, 16GB RAM, 150GB SSD)
• Cost: ~$0.008/min vs $0.008/min for standard
• ❌ Not needed after cleanup optimization

Option B: Self-Hosted Runner

• Requires dedicated server with 50GB+ disk
• ❌ Overkill for current project

Option C: Split into Smaller Jobs

• Separate workflows for each platform
• ❌ Increases complexity, slower overall

References

• jlumbroso/free-disk-space
• Gradle Best Practices in CI
• GitHub Actions Runner Specs