Dockerfile

# syntax=docker/dockerfile:1

# Flask + PostgreSQL + OpenTelemetry Example
# Python 3.14 | Dec 2025

# =============================================================================
# Builder Stage
# =============================================================================
FROM python:3.14-slim AS builder

WORKDIR /build

# Install build dependencies
RUN apt-get update && apt-get install -y --no-install-recommends \
    build-essential \
    libpq-dev \
    && rm -rf /var/lib/apt/lists/*

# Install Python dependencies
COPY requirements.txt .
RUN pip install --no-cache-dir --prefix=/install -r requirements.txt

# =============================================================================
# Runtime Stage
# =============================================================================
FROM python:3.14-slim AS runtime

# Security: Run as non-root user
RUN groupadd -r appgroup && useradd -r -g appgroup appuser

WORKDIR /app

# Install runtime dependencies only
RUN apt-get update && apt-get install -y --no-install-recommends \
    libpq5 \
    curl \
    && rm -rf /var/lib/apt/lists/*

# Copy installed packages from builder
COPY --from=builder /install /usr/local

# Copy application code
COPY --chown=appuser:appgroup . .

# Environment configuration
ENV PYTHONUNBUFFERED=1 \
    PYTHONDONTWRITEBYTECODE=1 \
    PYTHONPATH=/app

# Switch to non-root user
USER appuser

# Expose port
EXPOSE 8000

# Health check
HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
    CMD curl -f http://localhost:8000/api/health || exit 1

# Default command: Gunicorn with 2 workers
CMD ["gunicorn", "--bind", "0.0.0.0:8000", "--workers", "2", "--timeout", "120", "wsgi:app"]