Improve docker image size with a 2 stages image

[chevdor]

This improves both build time and size of the docker image.
It also moves all the scripts under a scripts folder.

In order to optimize the build time, I split the build.sh script into a production build and a -demo one. This is however no longer used at all by the docker image building.

@pepyakin please let me know whether you find the split interesting to keep, otherwise, I will revert that part. I made sure the demos are still part of the CI.

[chevdor]

Short update on the progress here:

As it turns out, using the rust base image it not a good strategy as it results in a binary that misses libssl when using slim images.

• Test using phusion/baseimage:0.10.1 for the 2 stages => 274 MB
• Test using phusion/baseimage:0.10.1 for the build and the smaller ubuntu:18.10 as second stage => 103MB but libssl failure.
• Test using phusion/baseimage:0.10.1 for the build and alpine:latest for the runtime.

The latest is much much smaller and has no known vulnerability.

Failure with ubuntu:18.10 is:

polkadot: error while loading shared libraries: libssl.so.1.0.0: cannot open shared object file: No such file or directory

[chevdor]

The libssl issue is solvable with the following in the second stage when using ubuntu:18.10:

apt-get update
apt-get install -y  libssl1.0.0 libssl-dev
# cd /lib/x86_64-linux-gnu
# ln -s libssl.so.1.0.0 libssl.so.10
# ln -s libcrypto.so.1.0.0 libcrypto.so.10

it results in a running polkadot but failing to connect to telemetry.

[chevdor]

After lots of testing here is the conclusion (I will also fix this PR). The best I got was:

• a running polkadot with telemetry broken in 74MB compressed
• a running polkadot with telemetry functionnal in 88MB compressed (version below).

dockerfile

``` FROM phusion/baseimage:0.10.1 as builder LABEL maintainer "[email protected]" LABEL description="This is the build stage for Polkadot. Here we create the binary."

ARG PROFILE=release
WORKDIR /polkadot

COPY . /polkadot

RUN apt-get update &&
apt-get upgrade -y &&
apt-get install -y cmake pkg-config libssl-dev git

RUN curl https://sh.rustup.rs -sSf | sh -s -- -y &&
export PATH=$PATH:$HOME/.cargo/bin &&
# rustup update nightly &&
# rustup target add wasm32-unknown-unknown --toolchain nightly &&
# rustup update stable &&
# cargo install --git https://github.com/alexcrichton/wasm-gc &&
cargo build --$PROFILE

===== SECOND STAGE ======

FROM phusion/baseimage:0.10.0
LABEL maintainer "[email protected]"
LABEL description="This is the 2nd stage: a very small image where we copy the Polkadot binary."
ARG PROFILE=release
COPY --from=builder /polkadot/target/$PROFILE/polkadot /usr/local/bin

RUN mv /usr/share/ca* /tmp &&
rm -rf /usr/share/* &&
mv /tmp/ca-certificates /usr/share/ &&
rm -rf /usr/lib/python* &&
mkdir -p /root/.local/share/Polkadot &&
ln -s /root/.local/share/Polkadot /data

RUN rm -rf /usr/bin /usr/sbin

EXPOSE 30333 9933 9944
VOLUME ["/data"]

CMD ["/usr/local/bin/polkadot"]

</details>

[adrianbrink]

I think this can be changed to mv /usr/share/ca-certificates /tmp, since you only move back ca-certificates 2 lines below.

[chevdor]

yes indeed, same effect, I have been lazy on that one :)