Add Docker Compose support with persistent SQLite volume

[nanotaboada]

Description

Currently, the project uses manual Docker build/run commands and stores the SQLite database inside the container filesystem. This violates container immutability and doesn’t persist data between runs.

Proposed Solution

Introduce Docker Compose to:

• Automate image building and container orchestration
• Mount a Docker-managed volume to persist the SQLite database across container restarts
• Copy a pre-seeded players-sqlite3.db from the image to the volume only on first run

Suggested Implementation

docker-compose.yml

services:
  api:
    image: python-samples-fastapi-restful
    container_name: fastapi-app
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "9000:9000"
    volumes:
      - storage:/storage/
    environment:
      - PYTHONUNBUFFERED=1
      - STORAGE_PATH=/storage/players-sqlite3.db
    restart: unless-stopped

volumes:
  storage:

Dockerfile

# Copy entrypoint sctipt and SQLite database
COPY --chown=root:root --chmod=755      scripts/entrypoint.sh       ./entrypoint.sh
COPY --chown=root:root --chmod=755      storage                     ./docker-compose

# Create non-root user and make volume mount point writable
RUN groupadd --system fastapi && \
    adduser --system --ingroup fastapi --disabled-password --gecos '' fastapi && \
    mkdir -p /storage && \
    chown fastapi:fastapi /storage

scripts/entrypoint.sh

#!/bin/bash
set -e

IMAGE_STORAGE_PATH="/app/docker-compose/players-sqlite3.db"
VOLUME_STORAGE_PATH="/storage/players-sqlite3.db"

echo "✔ Starting container..."

if [ ! -f "$VOLUME_STORAGE_PATH" ]; then
    echo "⚠️ No existing database file found in volume."
    if [ -f "$IMAGE_STORAGE_PATH" ]; then
        echo "Copying database file to writable volume..."
        cp "$IMAGE_STORAGE_PATH" "$VOLUME_STORAGE_PATH"
        echo "✔ Database initialized at $VOLUME_STORAGE_PATH"
    else
        echo "⚠️ Database file missing at $IMAGE_STORAGE_PATH"
        exit 1
    fi
else
    echo "✔ Existing database file found. Skipping seed copy."
fi

echo "✔ Ready!"
echo "🚀 Launching app..."
exec "$@"

Acceptance Criteria

• docker compose up builds and runs the container with FastAPI app on port 9000
• SQLite DB is copied to the volume only if not already present
• Data persists after docker compose down and is restored on next up
• docker compose down -v resets the DB, and re-seeds it on next run
• README.md is updated with Compose usage instructions