Urbit Alpine with optional swapfile setup

Dockerfile

FROM alpine:latest

EXPOSE 80/tcp
EXPOSE 34343/udp

COPY ./bin/start-urbit /bin/start-urbit
COPY ./bin/get-urbit-code /bin/get-urbit-code
COPY ./bin/reset-urbit-code /bin/reset-urbit-code

RUN apk add --no-cache curl bash libcap libc6-compat
RUN cd /bin && curl -L https://urbit.org/install/linux64/latest | tar xzk --strip=1
RUN setcap 'cap_net_bind_service=+ep' /bin/urbit

RUN mkdir -p /urbit
RUN mkdir -p /tmp
WORKDIR /urbit

CMD if [[ ! -z "$SWAP" ]]; then fallocate -l $(($(stat -f -c "(%a*%s/10)*7" .))) _swapfile && mkswap _swapfile && swapon _swapfile && ls -hla; fi; free -m; /bin/start-urbit