Switch to CUDA base image + cu121 torch to use GPU

Dockerfile

@@ -1,28 +1,27 @@
-FROM python:3.11-slim
+FROM nvidia/cuda:12.1.1-cudnn8-runtime-ubuntu22.04
 
 ENV DEBIAN_FRONTEND=noninteractive \
     OMP_NUM_THREADS=1
 
-# System libraries needed by OpenCV and ffmpeg
+# Python 3.10 (Ubuntu 22.04 default) is fine — basicsr locals() bug is 3.13+ only
 RUN apt-get update && apt-get install -y \
+    python3 python3-pip python3-dev \
     ffmpeg libsm6 libxext6 libgl1 \
-    && rm -rf /var/lib/apt/lists/*
+    && rm -rf /var/lib/apt/lists/* \
+    && ln -sf /usr/bin/python3 /usr/bin/python
 
-# Install torch as a separate layer so Docker can cache it across rebuilds
-RUN pip install --no-cache-dir \
+# Install torch with CUDA 12.1 support (compatible with CUDA 12.x hosts)
+RUN pip3 install --no-cache-dir \
     torch torchvision \
-    --index-url https://download.pytorch.org/whl/cpu
+    --index-url https://download.pytorch.org/whl/cu121
 
 WORKDIR /app
-# Copy files BEFORE pip install so basicsr_vendor is present
 COPY . .
 
-# Install basicsr from our vendored copy which has two patches applied:
-#   1. setup.py get_version() fix for Python 3.13+ (bonus: also works here)
-#   2. degradations.py import fix for torchvision >= 0.16
-RUN pip install --no-cache-dir ./basicsr_vendor
+# Install basicsr from vendored patched source
+RUN pip3 install --no-cache-dir ./basicsr_vendor
 
-RUN pip install --no-cache-dir \
+RUN pip3 install --no-cache-dir \
     "realesrgan>=0.3.0" \
     "opencv-python-headless>=4.8.0" \
     "numpy>=1.24.0" \
@@ -36,4 +35,4 @@ USER user
 ENV HOME=/home/user PATH=/home/user/.local/bin:$PATH
 
 EXPOSE 7860
-CMD ["python", "app.py"]
+CMD ["python3", "app.py"]