Encrypt tar gz file in Dockerfile

README.md

build it

docker build --build-arg KEY=myKey -t encrypted 

Run it

instance=$(docker run -v $(pwd):/code -e DEST=/code -e KEY=myKey -w /code -d encrypted)
docker exec -it $instance ls /code

Dockerfile

FROM alpine:3.12
RUN apk add --update --no-cache openssl
WORKDIR /src
COPY . .
WORKDIR /dest
ARG KEY
ENV KEY=${KEY}
# compress them &&
RUN tar -C /src -cvzf clear.tgz . &&\
     openssl enc -aes-256-cbc -in clear.tgz -out notclear.tgz.enc -pass env:KEY && \
     rm -rf /src && unset KEY && rm -rf clear.tgz
COPY entrypoint /bin/entrypoint
ENTRYPOINT ["sh", "/bin/entrypoint"]

entrypoint

#!/bin/sh
if [ -d "${DEST}" ]; then
 openssl enc -aes-256-cbc -d -in /dest/notclear.tgz.enc -out /dest/notclear.tgz -pass env:PROT
 tar -C ${DEST} -xzvf /dest/notclear.tgz
fi

if [ $# -eq 0 ]; then
 echo "CMD is empty ${@}"
 exec tail -f /dev/null
else
 echo "CMD is considered ${@}"
 exec $@

fi