Mathias Beaulieu-Duncan 26797d954d Update web example with WASM build and static-web-server

- Use --wasm flag for WebAssembly compilation
- Add cache-busting for JS/WASM assets
- Replace nginx with static-web-server on scratch (~18MB)
- Run as non-root user

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

2026-02-03 03:56:27 -05:00

5.9 KiB

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Flutter SDK Docker Images

Lightweight Flutter SDK images for CI/CD pipelines. Built on Wolfi, a security-focused Linux distribution designed for containers.

Images

Variant	Use Case	Size	Arch
	Web/WASM builds
	Android APK/AAB builds
	Linux desktop builds

Why Wolfi?

Wolfi is a lightweight Linux distribution built specifically for containers. It provides:

Minimal footprint - Only essential packages, nothing extra
Daily security updates - Patches applied quickly
Designed for containers - No legacy cruft from traditional distros

Features

Lightweight - Optimized for fast CI/CD pulls
Secure - Built on Wolfi with continuous vulnerability scanning
Multi-arch - Supports both linux/amd64 and linux/arm64
Non-root - Runs as unprivileged user (UID 65532)
Supply chain security - SBOM and SLSA provenance attestations included

Dockerfile Examples

Web App (WASM)

FROM svrnty/flutter-sdk:web-latest AS build
WORKDIR /app
COPY . .
RUN flutter pub get && flutter build web --wasm --release

# Cache-busting: append version to JS/WASM references
RUN VERSION=$(date +%s) && cd build/web && \
    sed -i "s|flutter_bootstrap\.js\"|flutter_bootstrap.js?v=${VERSION}\"|g" index.html && \
    sed -i "s|main\.dart\.js\"|main.dart.js?v=${VERSION}\"|g" flutter_bootstrap.js && \
    sed -i "s|main\.dart\.mjs\"|main.dart.mjs?v=${VERSION}\"|g" flutter_bootstrap.js && \
    sed -i "s|main\.dart\.wasm\"|main.dart.wasm?v=${VERSION}\"|g" flutter_bootstrap.js

FROM ghcr.io/static-web-server/static-web-server:2 AS sws
FROM scratch
COPY --from=sws /static-web-server /static-web-server
COPY --from=build /app/build/web /public
EXPOSE 8080
USER 65534
ENTRYPOINT ["/static-web-server", "-p", "8080", "-d", "/public"]

Android APK

FROM svrnty/flutter-sdk:android-latest AS build
COPY . /app
WORKDIR /app
RUN flutter pub get && flutter build apk --release

FROM scratch
COPY --from=build /app/build/app/outputs/flutter-apk/app-release.apk /

Linux Desktop

FROM svrnty/flutter-sdk:linux-latest AS build
COPY . /app
WORKDIR /app
RUN flutter pub get && flutter build linux --release

FROM ubuntu:22.04
RUN apt-get update && apt-get install -y libgtk-3-0 && rm -rf /var/lib/apt/lists/*
COPY --from=build /app/build/linux/x64/release/bundle /app
ENTRYPOINT ["/app/my_app"]

CI/CD

# GitHub Actions / Gitea Actions
jobs:
  build:
    runs-on: ubuntu-latest
    container:
      image: svrnty/flutter-sdk:android-latest
    steps:
      - uses: actions/checkout@v4
      - run: flutter pub get
      - run: flutter build apk --release

# GitLab CI
build:
  image: svrnty/flutter-sdk:android-latest
  script:
    - flutter pub get
    - flutter build apk --release

Automatic Updates

Images are automatically rebuilt when:

New Flutter stable versions are released
Base image security updates are available

Every build is scanned and includes supply chain attestations (SBOM, SLSA provenance).

License

MIT

5.9 KiB Raw Blame History