Fix Docker builds on Raspberry Pi

[rjanja]

Summary

Docker build on Raspberry Pi is failing on Alpine 3.13:

Step 7/11 : RUN apk add tzdata
 ---> Running in ec28ac240ffc
fetch https://dl-cdn.alpinelinux.org/alpine/v3.13/main/armv7/APKINDEX.tar.gz
ERROR: https://dl-cdn.alpinelinux.org/alpine/v3.13/main: temporary error (try again later)
WARNING: Ignoring https://dl-cdn.alpinelinux.org/alpine/v3.13/main: No such file or directory
fetch https://dl-cdn.alpinelinux.org/alpine/v3.13/community/armv7/APKINDEX.tar.gz
ERROR: https://dl-cdn.alpinelinux.org/alpine/v3.13/community: temporary error (try again later)
WARNING: Ignoring https://dl-cdn.alpinelinux.org/alpine/v3.13/community: No such file or directory
ERROR: unable to select packages:
  tzdata (no such package):
    required by: world[tzdata]
The command '/bin/sh -c apk add tzdata' returned a non-zero code: 1

While I thought it was related to network settings or container permissions, it turned out to be an effect of alpinelinux/docker-alpine#135.

From the Alpine 3.13 release notes:

Alpine Linux 3.13.0 requires the host Docker to be version 19.03.9 (which contains backported moby commit 89fabf0) or greater and the host libseccomp to be version 2.4.2 (which contains backported libseccomp commit bf747eb) or greater

On Raspbian buster, libseccomp is at 2.3.3-4. I'm not sure if there are prebuilt packages available for >=2.4.2 but that would be another option for resolving this.

Approach

This PR adds a build argument for image name and defaults it to what it was, and updates docs for Raspberry Pi docker build to use a currently-working Alpine version.

Feedback

• Should image name argument include the entire image name, not just something under the python namespace?

P.S. thank you for your work on this! I have not even had a chance to run it yet but am excited to try it! 🎉

[Odianosen25]

Thanks for this @rjanja, if we are going to do this, then allow for the whole image to improve on flexibility.

Regards

[rjanja]

Thanks for this @rjanja, if we are going to do this, then allow for the whole image to improve on flexibility.

Thanks for the quick review! I've updated the PR to allow the entire image name to be specified.