Update to debian 12. Install dependencies via venv to avoi useless copy files in next stage and reduce image size. Better apt-get install and no upgrade. Removed wheel install because already specified in requirements.txt. Use groupadd and useradd instead of addgroup and adduser. Copy entire folder, useless files are ignored via dockerignore. Set PATH to venv. Added TZ specification.

Dockerfile

@@ -1,39 +1,33 @@
-FROM python:3.9-slim-bullseye AS PREBUILD
+FROM python:3.9-slim-bookworm AS builder
+
+COPY requirements.txt .
 
 # Install dependencies
-RUN apt-get update && apt-get -y upgrade && apt-get install -y git-core
+RUN apt-get update && apt-get install -y --no-install-recommends git && \
+    rm -rf /var/lib/apt/lists/* && \
+    python3 -m venv /opt/netbox-sync/venv && \
+    /opt/netbox-sync/venv/bin/python3 -m pip install --upgrade pip && \
+    /opt/netbox-sync/venv/bin/pip install -r requirements.txt && \
+    /opt/netbox-sync/venv/bin/pip install --upgrade git+https://github.com/vmware/vsphere-automation-sdk-python.git
 
-COPY requirements.txt /tmp/requirements.txt
+FROM python:3.9-slim-bookworm AS netbox-sync
 
-RUN pip3 install --upgrade pip && \
-    pip3 install wheel && \
-    pip3 install -r /tmp/requirements.txt && \
-    pip3 install --upgrade git+https://github.com/vmware/vsphere-automation-sdk-python.git
+# Copy installed packages
+COPY --from=builder /opt/netbox-sync/venv /opt/netbox-sync/venv
 
-
-FROM python:3.9-slim-bullseye
-
-# Install dependencies
-RUN apt-get update && apt-get -y upgrade
-
-# Run the application
-WORKDIR /app
-
-RUN set -eux; \
-  addgroup --gid 1000 netbox-sync; \
-  adduser --uid 1000 --ingroup netbox-sync --shell /bin/sh --home /home/netbox-sync --disabled-password \
-          --gecos "netbox-sync,0815,2342,9001" netbox-sync
-
-# Prepare the application
-COPY Dockerfile LICENSE.txt netbox-sync.py README.md requirements.txt settings-example.ini /app/
-COPY module /app/module
-
-RUN chown -R netbox-sync:netbox-sync /app
-
-# disable upgrading setup tools due to bug in setuptools and automation sdk
-# once this is fixed, switch back to: pip3 install --upgrade pip setuptools
-COPY --from=PREBUILD /usr/local /usr/local
+# Add netbox-sync user
+RUN groupadd --gid 1000 netbox-sync && \
+    useradd --uid 1000 --gid netbox-sync --shell /bin/sh \ 
+    --no-create-home --system netbox-sync
 
 USER netbox-sync
 
+# Prepare the application
+WORKDIR /app
+COPY --chown=netbox-sync:netbox-sync . .
+
+# Use virtual env packages and allow timezone setup
+ENV PATH=/opt/netbox-sync/venv/bin:$PATH
+ENV TZ=Europe/Berlin
+
 ENTRYPOINT ["python3", "netbox-sync.py"]