FROM python:3.11-slim

# Runtime defaults for Python and Streamlit in containers.
ENV PYTHONDONTWRITEBYTECODE=1 \
    PYTHONUNBUFFERED=1 \
    PIP_NO_CACHE_DIR=1 

WORKDIR /app

# Install Python dependencies first for better layer caching.
COPY requirements.txt ./
RUN pip install --upgrade pip \
    && pip install -r requirements.txt

# Copy app source.
COPY app.py ./

EXPOSE 8501

HEALTHCHECK --interval=30s --timeout=5s --start-period=20s --retries=3 \
    CMD python -c "import urllib.request; urllib.request.urlopen('http://localhost:8501/_stcore/health', timeout=3)"

CMD ["streamlit", "run", "app.py", "--server.address=0.0.0.0", "--server.port=8501"]