Reduced image size furtherly. Now 329MB and based on python:alpine.

docker/Dockerfile

@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1
 
-FROM alpine:latest
+FROM python:alpine
 
 ENV TZ=Europe/Berlin
 ENV UNBUFFERED=1
@@ -11,9 +11,17 @@ VOLUME /app
 COPY . .
 
 RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone; \
-    /bin/sh -c 'apk update && apk add --no-cache gcc musl-dev python3-dev py3-pip libffi-dev openssl-dev cargo zlib-dev jpeg-dev speex ffmpeg htop; \
-    pip install update pip && pip install -r requirements.txt ; \
-    apk del zlib-dev jpeg-dev gcc musl-dev python3-dev libffi-dev openssl-dev cargo;'
+    apk --no-cache update && apk add --no-cache  --virtual .build-deps \
+    gcc \
+    cargo \
+    libffi-dev \
+    openssl-dev \
+    zlib-dev \
+    jpeg-dev ; \
+    apk add --no-cache ffmpeg speex; \
+    pip install --no-cache-dir upgrade pip; \
+    pip install --no-cache-dir -r requirements.txt ; \
+    apk del --no-cache .build-deps;