Dockerfile

# Use a specific Python 3.10 base image for better stability with faiss-cpu.
FROM python:3.10-slim-bookworm

# Set environment variables for non-buffered Python output and explicit Python path.
ENV PYTHONUNBUFFERED=1
# Set the default Python executable for consistency.
ENV PATH="/usr/local/bin:${PATH}"

# Set the working directory inside the container.
WORKDIR /app

# Install essential system dependencies.
RUN apt-get update && apt-get install -y --no-install-recommends \
    git \
    git-lfs \
    ffmpeg \
    libsm6 \
    libxext6 \
    cmake \
    rsync \
    libgl1-mesa-glx \
    curl \
    && rm -rf /var/lib/apt/lists/* \
    && apt-get clean \
    && git lfs install

# Install Node.js, which Gradio requires.
RUN curl -fsSL https://deb.nodesource.com/setup_20.x | bash - \
    && apt-get install -y nodejs \
    && rm -rf /var/lib/apt/lists/*

# Create a non-root user and switch to it.
# This is a best practice for security and can resolve some permission-related issues.
RUN useradd -m -u 1000 user
USER user

# Copy requirements.txt and install Python dependencies.
# This is done before copying the rest of the app to leverage Docker layer caching.
COPY --chown=user:user requirements.txt .

# --- START OF CRITICAL INSTALLATION BLOCK ---
# Upgrade pip to the latest version.
RUN pip install --no-cache-dir --upgrade pip

# Install core deep learning and Gradio packages.
# Using --break-system-packages (if needed for pip 23.x+) to avoid default Python conflicts.
# The --target flag explicitly installs into site-packages, which should be on PYTHONPATH.
RUN pip install --no-cache-dir \
    torch==2.0.0 \
    sentence-transformers==2.5.1 \
    faiss-cpu==1.7.4 \
    gradio==4.28.3 \
    --index-url https://download.pytorch.org/whl/cpu && \
    pip install --no-cache-dir -r requirements.txt

# Verify installation with pip check and direct import.
RUN pip check || echo "pip check found issues!"
RUN python3 -c "try: import sentence_transformers; print('sentence_transformers imported successfully in build step!')\nexcept ImportError as e: print(f'Failed to import sentence_transformers in build step: {e}'); exit(1)"
# --- END OF CRITICAL INSTALLATION BLOCK ---

# Copy all your application files into the container, owned by the 'user'.
COPY --chown=user:user . .

# Define the command that will run your application when the Space starts.
# Using 'python3' explicitly.
CMD ["python3", "app.py"]