Dockerfile

# Hugging Face Space (SDK: docker) -- listens on 7860.
#
# NOTE: python:3.9 from the stock HF template does NOT work for this app.
# FastAPI/Pydantic evaluate annotations like `str | None` at runtime, which
# requires Python 3.10+. 3.11 matches the development environment.
FROM python:3.11-slim

WORKDIR /code

# Install CPU-only torch first -- the default PyPI wheel pulls ~2.5GB of CUDA
# libraries that a CPU Space can never use.
RUN pip install --no-cache-dir --upgrade pip && \
    pip install --no-cache-dir torch --index-url https://download.pytorch.org/whl/cpu

COPY ./requirements.txt /code/requirements.txt
RUN pip install --no-cache-dir --upgrade -r /code/requirements.txt

# Set up a new user named "user" with user ID 1000
RUN useradd -m -u 1000 user
USER user
ENV HOME=/home/user \
    PATH=/home/user/.local/bin:$PATH

# Model + SQLite both need writable paths. On a Space, $HOME is the only one.
ENV HF_HOME=/home/user/.cache/huggingface \
    DATA_DIR=/home/user/app/data \
    MODEL_NAME=typeform/distilbert-base-uncased-mnli \
    PRELOAD_MODEL=1 \
    PYTHONUNBUFFERED=1

WORKDIR $HOME/app

# Bake the model into the image so the Space answers the first request fast
# instead of downloading ~250MB on cold start.
RUN python -c "\
from transformers import pipeline; \
import os; \
pipeline('zero-shot-classification', model=os.environ['MODEL_NAME'], device=-1)" \
    && echo "model cached"

COPY --chown=user . $HOME/app

RUN mkdir -p $HOME/app/data

EXPOSE 7860

# app.main:app -- the FastAPI instance lives in the `app` package, not main.py
CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "7860"]