1# https://docs.docker.com/engine/reference/builder/#from 2# "The FROM instruction initializes a new build stage and sets the 3# Base Image for subsequent instructions." 4FROM erlang:20.3.8.1-alpine as builder 5# https://docs.docker.com/engine/reference/builder/#label 6# "The LABEL instruction adds metadata to an image." 7LABEL stage=builder 8 9# Install git for fetching non-hex depenencies. Also allows rebar3 10# to find it's own git version. 11# Add any other Alpine libraries needed to compile the project here. 12# See https://wiki.alpinelinux.org/wiki/Local_APK_cache for details 13# on the local cache and need for the symlink 14RUN ln -s /var/cache/apk /etc/apk/cache && \ 15 apk update && \ 16 apk add --update openssh-client git 17 18# WORKDIR is located in the image 19# https://docs.docker.com/engine/reference/builder/#workdir 20WORKDIR /root/rebar3 21 22# copy the entire src over and build 23COPY . . 24RUN ./bootstrap 25 26# this is the final runner layer, notice how it diverges from the original erlang 27# alpine layer, this means this layer won't have any of the other stuff that was 28# generated previously (deps, build, etc) 29FROM erlang:20.3.8.1-alpine as runner 30 31# copy the generated `rebar3` binary over here 32COPY --from=builder /root/rebar3/_build/prod/bin/rebar3 . 33 34# and install it 35RUN HOME=/opt ./rebar3 local install \ 36 && rm -f /usr/local/bin/rebar3 \ 37 && ln /opt/.cache/rebar3/bin/rebar3 /usr/local/bin/rebar3 \ 38 && rm -rf rebar3 39 40# simply print out the version for visibility 41ENTRYPOINT ["/usr/local/bin/rebar3"] 42CMD ["--version"] 43 44