2-step docker build for arm/v6 and arm/v7

Dockerfile

@@ -1,10 +1,21 @@
-FROM python:3-alpine
+FROM python:3.12-alpine as builder
+
+RUN set -eux; \
+        apk add --no-cache \
+                gcc \
+                libc-dev \
+                libffi-dev
 
 WORKDIR /app
 
 COPY requirements.txt ./
 RUN pip install --no-cache-dir -r requirements.txt
 
+FROM python:3.12-alpine
+
+WORKDIR /app
+
+COPY --from=builder /usr/local/lib/python3.12/site-packages /usr/local/lib/python3.12/site-packages
 COPY knx2mqtt .
 
 CMD [ "python", "./knx2mqtt" ]