ejemplo de dockerfile
FROM ubuntu:18.04
COPY . /app
RUN make /app
CMD python /app/app.py
docker ARG
$ docker build --build-arg some_variable_name=a_value
dockerfile env variabes
FROM busybox
ENV foo /bar
WORKDIR ${foo} # WORKDIR /bar
ADD . $foo # ADD . /bar
COPY \$foo /quux # COPY $foo /quux