Dockerfile.production

# Multi-stage Docker build for Python Flask Chat Server
# Optimized for production deployment with smaller image size

# Build stage
FROM python:3.11-slim as builder

# Set environment variables
ENV PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1 \
    PIP_NO_CACHE_DIR=1 \
    PIP_DISABLE_PIP_VERSION_CHECK=1

# Install system dependencies for building
RUN apt-get update && apt-get install -y \
    build-essential \
    gcc \
    g++ \
    cmake \
    pkg-config \
    && rm -rf /var/lib/apt/lists/*

# Create and activate virtual environment
RUN python -m venv /opt/venv
ENV PATH="/opt/venv/bin:$PATH"

# Copy requirements and install Python dependencies
COPY requirements.txt .
RUN pip install --no-cache-dir -r requirements.txt

# Production stage
FROM python:3.11-slim

# Set environment variables
ENV PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1 \
    PATH="/opt/venv/bin:$PATH" \
    FLASK_ENV=production \
    FLASK_PORT=5000

# Install runtime dependencies
RUN apt-get update && apt-get install -y \
    curl \
    && rm -rf /var/lib/apt/lists/* \
    && apt-get clean

# Copy virtual environment from builder stage
COPY --from=builder /opt/venv /opt/venv

# Create non-root user for security
RUN groupadd -r appgroup && useradd -r -g appgroup -d /app -s /bin/bash appuser

# Create application directory
WORKDIR /app

# Copy application code
COPY src/ ./src/
COPY .env* ./

# Create necessary directories and set permissions
RUN mkdir -p /app/logs /app/cache \
    && chown -R appuser:appgroup /app

# Switch to non-root user
USER appuser

# Expose port
EXPOSE 5000

# Health check
HEALTHCHECK --interval=30s --timeout=10s --start-period=5s --retries=3 \
    CMD curl -f http://localhost:5000/health || exit 1

# Set working directory to src for proper module imports
WORKDIR /app/src

# Default command
CMD ["python", "chat_server.py"]