FROM alpine:3.8

RUN apk add --no-cache openssh-client

COPY entrypoint.sh /
RUN chmod a+rx /entrypoint.sh
ENTRYPOINT ["/entrypoint.sh"]

COPY ssh_config /etc/ssh/ssh_config
RUN chmod a=r /etc/ssh/ssh_config

RUN adduser -S tunnel
COPY --chown=tunnel:nogroup known_hosts /home/tunnel/.ssh/known_hosts
USER tunnel

ENV BIND_ADDRESS bind-address
ENV BIND_PORT 22
CMD ssh -T -R $BIND_ADDRESS:$BIND_PORT:$DOCKER_HOST_ADDRESS:22 serveo.net