Update python.md

Author: MichaelCurrin

recipes/containers/docker/python.md

@@ -40,6 +40,31 @@ container:
 	docker run --rm myapp
 ```
 
+Multi-stage build, to avoid dev tools in the final image.
+
+
+```dockerfile
+FROM python:3.9-slim-buster as builder
+
+WORKDIR /app
+
+COPY requirements.txt .
+RUN pip install --no-cache-dir -r requirements.txt
+
+COPY . .
+
+FROM python:3.9-slim-buster
+
+WORKDIR /app
+
+COPY --from=builder /usr/local/lib/python3.9/site-packages /usr/local/lib/python3.9/site-packages
+COPY --from=builder /app .
+
+EXPOSE 8000
+
+CMD ["python", "app.py"]
+```
+
 
 ## CLI only