Update Dockerfile

Dockerfile

@@ -2,7 +2,6 @@ FROM ubuntu:22.04
 
 ENV DEBIAN_FRONTEND=noninteractive
 
-# ---- system deps ----
 RUN apt-get update \
  && apt-get install -y --no-install-recommends \
       build-essential \
@@ -21,12 +20,9 @@ RUN curl -LsSf https://astral.sh/uv/install.sh | sh \
 
 # Put uv-managed python somewhere world-readable
 ENV UV_PYTHON_INSTALL_DIR=/opt/uv/python
-ENV UV_CACHE_DIR=/opt/uv/cache
-
-RUN mkdir -p /opt/uv/python /opt/uv/cache \
+RUN mkdir -p /opt/uv/python \
  && chmod -R 755 /opt/uv
 
-# ---- install Python via uv ----
 ARG PYTHON_VERSION=3.12.12
 RUN uv python install ${PYTHON_VERSION}
 
@@ -35,25 +31,25 @@ ARG OPENTRONS_REF=edge
 RUN git clone --depth 1 --branch ${OPENTRONS_REF} https://github.com/Opentrons/opentrons.git /root/opentrons
 
 WORKDIR /root/opentrons
-
-# ---- robot-server setup ----
 RUN uv run --python ${PYTHON_VERSION} make -C robot-server setup
 
 # ---- app user ----
 RUN useradd -m -u 1000 user
 USER user
+
 ENV HOME=/home/user
+# ✅ cache goes to a writable location
+ENV UV_CACHE_DIR=/home/user/.cache/uv
 
 WORKDIR $HOME/app
 
-# cache-friendly deps install
+RUN mkdir -p $UV_CACHE_DIR
+
 COPY --chown=user requirements.txt $HOME/app/requirements.txt
 
-# create venv + install deps (user can run uv now)
 RUN uv venv --python ${PYTHON_VERSION} .venv \
  && uv pip install --python .venv/bin/python -r requirements.txt
 
-# copy app
 COPY --chown=user . $HOME/app
 
 # ---- entrypoint ----