Alpine Docker image

[camo-f]

Hello,

Here is my Dockerfile to use Alpine Linux instead of Debian and build in a container. I ended up with an ~83MB image.

FROM node:11-alpine AS build

RUN apk add -U --no-cache build-base # Add git to run git commands in make
COPY . /salty-dog
WORKDIR /salty-dog
RUN make

FROM node:11-alpine

# copy config, which changes rarely
COPY docs/config-docker.yml /root/.salty-dog.yml

# copy package first, to invalidate other layers when version changes
COPY package.json /salty-dog/package.json

# copy chunks, largest to smallest (entrypoint)
COPY --from=build /salty-dog/out/vendor.js /salty-dog/out/vendor.js
COPY --from=build /salty-dog/out/main.js /salty-dog/out/main.js
COPY --from=build /salty-dog/out/index.js /salty-dog/out/index.js

# set up as global cli tool
WORKDIR /salty-dog
RUN yarn global add file:$(pwd)
ENV PATH="${PATH}:$(yarn global bin)"

COPY rules /salty-dog/rules

ENTRYPOINT [ "node", "/salty-dog/out/index.js" ]
CMD [ "--help" ]

It also implies minor changes to test-examples.sh to make it shell compliant.

Do you see any problem moving to Alpine ? If any, we may simply add a new image with a specific tag alpine.
I can make a PR if you want.

[ssube]

Hi, thanks for the suggestion! I have no problems adding an Alpine image, and your Dockerfile looks good - will give it a try later and fix up test-examples.sh as needed. I'd like to keep a stretch image (run a deb/ubuntu-based env as much as possible), so there will be a small CI tweak to build both and add the -alpine suffix, but I can make that.

Feel free to PR the Dockerfile by itself or with the script fixes, and I'll get it into CI and tag a release.

We may also be able to leave test-examples.sh as-is by reusing the bundle from the build-node job in CI, which has already run those tests. That won't help with local builds, however. 🤔

[camo-f]

It seems to work when building with Stretch and then running in Alpine. Is it what you're doing during CI ?
If we want to use Alpine for build, we need to add build-base package in the image since make is not installed by default.
If we can keep Stretch for build, updating test-examples was indeed not necessary, but it is minor changes.

For local builds with Docker :

# Stretch
docker run --rm -v "$(pwd):/salty-dog" -w /salty-dog node:11-stretch make
docker build -t salty-dog:stretch -f Dockerfile.stretch .
# Alpine
docker run --rm -v "$(pwd):/salty-dog" -w /salty-dog node:11-alpine sh -c "apk add build-base && make"
docker build -t salty-dog:alpine -f Dockerfile.alpine .

Maybe we could add the instructions to the readme ?

[ssube]

Yep, reusing the stretch-built files is exactly what I meant. Thanks for the PR, I've merged your changes and built an image from this branch: https://hub.docker.com/r/ssube/salty-dog/tags?page=1&name=alpine (it's tagged with branch-slug-alpine until I merge to master). Passes the tests and looks good to me, if you agree I will get it released.

[camo-f]

Seems ready for release to me. Thank you !

[ssube]

Merged, tagged, and built.