Dockerfile

FROM python:3.11-slim
WORKDIR /app

ENV PIP_NO_CACHE_DIR=1 PYTHONDONTWRITEBYTECODE=1 PYTHONUNBUFFERED=1

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

COPY requirements.txt .
RUN pip install --upgrade pip && pip install -r requirements.txt

# copy only what we need; fewer surprises
COPY app.py app.py

ENV PORT=7860
EXPOSE 7860

# 🔑 Use *shell form* so $PORT expands; JSON form won't expand ${PORT}
CMD bash -lc 'streamlit run app.py --server.address=0.0.0.0 --server.port ${PORT:-7860}'