ARG DISTRO=alpine:3.14.2 FROM $DISTRO # python3 shared with most images RUN apk add --no-cache \ python3 py3-pip bash \ && pip3 install --upgrade pip # Image specific layers under this line RUN apk add --no-cache fetchmail ca-certificates openssl \ && pip3 install requests COPY fetchmail.py /fetchmail.py USER fetchmail CMD ["/fetchmail.py"]