jashem/flutter-ci

Flutter CI Docker Image

This repository contains an ultra-optimized Docker image for Flutter CI/CD pipelines, specifically designed to provide fast builds with pre-installed Android SDK components and optimized memory settings for 12GB RAM environments.

Features

• Ultra Small: ~400MB (vs 1.2GB+ for Ubuntu-based images)
• Complete Environment: Includes all tools needed for Flutter CI/CD
• Alpine Linux Base: Lightweight and secure
• Pre-installed Android SDK Components: Eliminates CI download delays
• Memory Optimized: Configured for 12GB RAM environments
• Fast Builds: 5-10+ minutes faster CI builds with no SDK downloads
• All Dependencies Pre-installed: Flutter, Android SDK, OpenJDK, Ruby/Fastlane, Python/Google APIs

Included Components

Development Tools

• Flutter SDK: Version 3.35.4 (stable)
• Android SDK:
  • Command Line Tools (latest)
  • Platform Tools (latest)
  • Multiple Platforms: Android-36, Android-35, Android-34, Android-33, Android-31
  • Build Tools: 36.0.0 and 35.0.0
  • NDK: Version 28.2.*** (pre-installed for native compilation)
• OpenJDK: Version 17
• Ruby: With Bundler 2.6.9 and Fastlane
• Python 3: With Google API client libraries

Memory Configuration (12GB RAM Optimized)

• Gradle JVM: 11GB heap with G1GC and string deduplication
• Kotlin Daemon: 8GB heap for fast compilation
• Metaspace: 1GB for Gradle, 512MB for Kotlin
• Workers: 4 parallel workers for optimal CPU utilization
• Additional Optimizations: VFS watching, compressed oops, daemon timeout

Environment Variables

bash
ANDROID_HOME=/opt/android-sdk
ANDROID_SDK_ROOT=/opt/android-sdk
JAVA_HOME=/usr/lib/jvm/java-17-openjdk
FLUTTER_ROOT=/opt/flutter
PATH=/opt/flutter/bin:/opt/android-sdk/cmdline-tools/latest/bin:/opt/android-sdk/platform-tools:$JAVA_HOME/bin:$PATH

Use in Docker Compose

yaml
version: '3.8'
services:
  flutter-ci:
    image: jashem/flutter-ci:3.35.4-v2
    volumes:
      - ./app:/workspace
      - gradle-cache:/root/.gradle
      - pub-cache:/root/.pub-cache
    working_dir: /workspace
    command: flutter build apk --release

Use in Drone CI

Replace ghcr.io/cirruslabs/flutter:3.35.4 with the optimized image:

yaml
steps:
- name: build-app
  image: jashem/flutter-ci:3.35.4-v2
  commands:
    - flutter pub get
    - flutter build apk --release

Benefits:

• ✅ No more SDK downloads during CI builds
• ✅ Pre-installed NDK for native compilation
• ✅ Optimized for 12GB RAM environments
• ✅ 5-10+ minutes faster builds

Optimization Techniques

1. Alpine Linux Base: Uses minimal Alpine Linux (5MB base vs 77MB Ubuntu)
2. glibc Compatibility: Uses gcompat for Android SDK compatibility
3. Layer Optimization: Single RUN layer for system packages
4. Package Cleanup: Automatic cache cleanup during build
5. Version Pinning: Exact versions for reproducible builds
6. Pre-installed SDK Components: Eliminates CI download delays
7. Memory Optimization: 12GB RAM configuration with G1GC and string deduplication
8. Parallel Processing: Optimized worker count and VFS watching

Cache Volumes for CI/CD

For optimal CI/CD performance, mount these volumes:

• /root/.gradle - Gradle dependencies
• /root/.pub-cache - Flutter packages
• /root/.local/share/gem - Ruby gems
• /root/.cache/pip - Python packages
• /var/cache/apt - System package cache (if needed)

Performance Comparison

CI Performance Improvements

Before (v3.35.4)

• ❌ NDK downloaded during every build (~2-3 minutes)
• ❌ Platform SDKs downloaded (31, 33, 34, 35) (~1-2 minutes)
• ❌ Build Tools 35 downloaded during build (~30 seconds)
• ❌ License acceptance during every build
• ❌ 10GB Gradle heap limit
• ❌ 4GB Kotlin daemon limit

After (v3.35.4-v2)

• ✅ All SDK components pre-installed
• ✅ NDK 28.2.*** pre-installed
• ✅ Platform SDKs 31, 33, 34, 35, 36 pre-installed
• ✅ Build Tools 35.0.0 & 36.0.0 pre-installed
• ✅ All licenses pre-accepted
• ✅ 11GB Gradle heap + G1GC optimization
• ✅ 8GB Kotlin daemon for fast compilation
• ✅ Memory optimized for 12GB RAM environments

Result: 5-10+ minutes faster CI builds with no download delays and optimized compilation performance.

Verification

• ✅ Flutter SDK installation and version
• ✅ Android SDK components and licenses
• ✅ NDK installation (28.2.***)
• ✅ Platform SDKs (31, 33, 34, 35, 36)
• ✅ Build Tools (35.0.0, 36.0.0)
• ✅ Fastlane installation
• ✅ Python Google API packages
• ✅ Memory configuration verification