Docker & Compose

IronFlock apps are packaged as Docker images. The Dockerfile defines the runtime environment for your application code.

Dockerfile

Every app requires a Dockerfile in the root folder. This file configures a Linux environment for your app, starting from a base image:

FROM python:3.11-slim
 
WORKDIR /app
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt
 
COPY . .
 
CMD ["python", "main.py"]

Refer to the official Dockerfile documentation for the full syntax reference.

Multi-Architecture Support

To target different device architectures, add architecture-specific Dockerfiles:

When building a release, IronFlock selects the most specific Dockerfile for each target architecture. If no architecture-specific file exists, the default Dockerfile is used.

Docker Compose

For apps with multiple services (e.g., a web server + a database + a worker), use Docker Compose:

# docker-compose.yml
version: "3"
services:
  app:
    build: .
    volumes:
      - /data:/data
      - /shared:/shared
    ports:
      - "5000:5000"
    restart: unless-stopped
 
  redis:
    image: redis:7-alpine
    restart: unless-stopped

Place the docker-compose.yml in the root folder instead of (or alongside) a Dockerfile. When users start or stop the app on their devices, the entire Compose stack is managed as a unit.

Docker Compose gives you more control over:

• Volume mounts and data persistence
• Service networking
• Resource limits
• Multi-container architectures

Best Practices

• Keep images small — Use -slim or -alpine base images to reduce download times on constrained devices.
• Pin versions — Use specific version tags (python:3.11-slim) instead of latest for reproducible builds.
• Cache layers — Copy dependency files before application code to leverage Docker layer caching.
• Use .dockerignore — Exclude unnecessary files (docs, tests, .git) from the build context.