10
Does a docker image minimizer like this exist?
(self.docker)
I am looking for something that can take a Dockerfile, like the following as an input:
FROM --platform=linux/amd64 debian:latest
ENV DEBIAN_FRONTEND=noninteractive
RUN apt update && apt install -y curl unzip libsecret-1-0 jq
COPY entrypoint.sh .
ENTRYPOINT [ "/entrypoint.sh" ]
And produce a a multi-stage Dockerfile where the last stage is built from scratch, with the dependencies for the script in the ENTRYPOINT (or CMD) copied over, like this:
FROM --platform=linux/amd64 debian:latest as builder
ENV DEBIAN_FRONTEND=noninteractive
RUN apt update && apt install -y curl unzip libsecret-1-0 jq
FROM --platform=linux/amd64 scratch as app
SHELL ["/bin/bash"]
# the binaries executed in entrypoint.sh
COPY --from=builder /bin/bash /bin/bash
COPY --from=builder /usr/bin/curl /usr/bin/curl
COPY --from=builder /usr/bin/jq /usr/bin/jq
COPY --from=builder /usr/bin/sleep /usr/bin/sleep
# shared libraries of the binaries
COPY --from=builder /lib/x86_64-linux-gnu/libjq.so.1 /lib/x86_64-linux-gnu/libjq.so.1
COPY --from=builder /lib/x86_64-linux-gnu/libcurl.so.4 /lib/x86_64-linux-gnu/libcurl.so.4
COPY --from=builder /lib/x86_64-linux-gnu/libz.so.1 /lib/x86_64-linux-gnu/libz.so.1
# ...a bunch of other shared libs...
# entrypoint
COPY entrypoint.sh /entrypoint.sh
ENTRYPOINT [ "/entrypoint.sh" ]
I've had pretty decent success creating images like this manually (using ldd to find the dependencies) based on this blog. To my knowledge, there's nothing out there that automates producing an image built from scratch, specifically. If something like this doesn't exist, I'm willing to build it myself.
Other than the example uses provided in the article, does anyone have any interesting ideas for how this could be used? The
RUST_LOG=debugone looks like it'll be particularly useful as an easy way to see what network requests a given binary might be making.