Dockerfile

# Docker Security Lab - Best Practices Dockerfile
# Follows Docker Scout policies and DHI best practices

# Stage 1: Builder
FROM python:3.11-slim AS builder

WORKDIR /build
COPY requirements.txt .
RUN pip wheel --no-cache-dir --wheel-dir /wheels -r requirements.txt

# Stage 2: Runtime
FROM python:3.11-slim

WORKDIR /app

# Install curl for healthcheck (clean up in same layer)
RUN apt-get update && \
    apt-get install -y --no-install-recommends curl && \
    rm -rf /var/lib/apt/lists/*

# Copy wheels from builder and install
COPY --from=builder /wheels /wheels
RUN pip install --no-cache-dir /wheels/*

# Create non-root user
RUN useradd -r -u 1001 -g root appuser

# Copy application code
COPY --chown=appuser:root src/ ./src/

# Switch to non-root user
USER appuser

EXPOSE 5000

HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
    CMD curl -f http://localhost:5000/health || exit 1

CMD ["python", "src/app.py"]