Dockerfile

# Base image
FROM python:3.12-slim

# Environment settings
ENV PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1 \
    PIP_NO_CACHE_DIR=1 \
    PIP_DISABLE_PIP_VERSION_CHECK=1 \
    FLASK_ENV=production \
    FLASK_DEBUG=0

# Working directory
WORKDIR /app

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

# Python dependencies first for better layer caching
COPY requirements.txt .

# Install Python dependencies
RUN pip install --upgrade pip setuptools wheel \
    && pip install -r requirements.txt \
    && pip install gunicorn \
    && apt-get purge -y --auto-remove build-essential gcc \
    && rm -rf /root/.cache/pip

# Application files
COPY . .

# Create non-root user and fix permissions
RUN useradd --create-home --shell /bin/bash appuser \
    && chown -R appuser:appuser /app

# Use non-root user
USER appuser

# Runtime port inside the container
EXPOSE 5000

# Start Flask app with Gunicorn
CMD ["gunicorn", "app:app", \
    "--bind", "0.0.0.0:5000", \
    "--workers", "2", \
    "--worker-class", "gthread", \
    "--threads", "4", \
    "--timeout", "180", \
    "--graceful-timeout", "30", \
    "--keep-alive", "5", \
    "--max-requests", "300", \
    "--max-requests-jitter", "30", \
    "--access-logfile", "-", \
    "--error-logfile", "-"]