Create Dockerfile.arm32v7

[anthonyraymond]

Description of change

Since the Dockerfile use the alpine image of Node, It's not multi-arch compliant. So here is a Dockerfile for arm32v7 platform (like raspberry).

A better option IMO would be to base the Dockerfile on node:8 instead of node:8-alpine, it will make it multi-arch compliant automatically. But i may understand if you don't wish to double the image size.

EDIT: i deliberately choosed stretch version to allow libopenzwave installation (if needed)

[Pierre-Gilles]

Nice work! One question: why Arm32v7 and not arm32v6? Here you're excluding all Raspberry Pi B/Zero!

[anthonyraymond]

Hi 😄

If you want arm32v6 the regular Dockerfile is the way to go,

Node is an official docker image, it means that from a unique base image (in this case node:8-alpine) you can build from multiple architecture (amd64, arm32v6, arm32v7, arm64v8, i386, ppc64le, s390x).
If you try to build the Dockerfile from an arm32v6 arch it will automatically download arm32v6/node:8-alpine base image.

This is the wonderfull theory of docker's multi-arch official image. But in the real world, it does not always work. In our case arm32v6/node:8-alpine will works, but the arm32v7/node does not have a 8-alpine tag so...

In this very case it's kinda weird since Debian and Alpine didn't quite understood on what is arm32v6 and arm32v7. See gliderlabs/docker-alpine#298 (comment)
This is the reason why arm32v7 does not have an alpine tag

[VonOx]

This is build problem or usage problem of current alpine image ?

Can you add nmap package ? ( Used by some module )

[VonOx]

After some reading, i have understood. This PR is a workaround

I think we need to use manifest to build multiarch images ( Gladys for ALL 😄 ) , but this require some learning/work/test.

For reference: https://docs.docker.com/registry/spec/manifest-v2-2/#manifest-list

[Pierre-Gilles]

I'm merging this in the meantime, this is a great PR :) We'll investigate for a multiarch image in the future!

Thanks!