docker: publish images to ghcr.io

[baloo]

Motivation

docker.com announced their intention to remove the free plan used by OSS. The nixos/nix image is essential to various CI runs to build with nix. To provide a continuity plan, this commit pushes the image to ghcr.io as well.

Context

Fixes #5778

Checklist for maintainers

Maintainers: tick if completed or explain if not relevant

• agreed on idea
• agreed on implementation strategy
• tests, as appropriate
  • functional tests - tests/**.sh
  • unit tests - src/*/tests
  • integration tests - tests/nixos/*
• documentation in the manual
• code and comments are self-explanatory
• commit message explains why the change was made
• new feature or incompatible change: updated release notes

Priorities

Add 👍 to pull requests you find important.

[SuperSandro2000]

You can get a token with enough permissions with

permissions:
  contents: read
  packages: write

[baloo]

You can get a token with enough permissions with

permissions:
  contents: read
  packages: write

I missed that! Thank you!

[baloo]

Made a test on my fork:
https://github.com/baloo/nix-1/actions/runs/4462632967/jobs/7837308039
https://github.com/baloo/nix-1/pkgs/container/nix-1
https://github.com/baloo/nix-1/blob/8800aa4530aec1f58601c63e7b4244a3b1248f3e/.github/workflows/ci.yml

That works as expected.

[fricklerhandwerk]

Triaged in the Nix team meeting 2023-03-23:

• The NixOS Foundation is in the process of applying to the Docker OSS program, so less of a priority
• postponed until there is more clarity on that application

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/2023-03-23-nix-team-meeting-minutes-43/26758/1

[baloo]

@fricklerhandwerk would there be any update on this?
I'm now hitting the rate limits of anonymous pulls as defined https://www.docker.com/increase-rate-limits/

There is the option of setting up authentication in the CI, but a more convenient mirror would be most welcome!

Thanks!

[fricklerhandwerk]

Discussed in 2023-10-13 Nix team meeting:

@baloo sorry for the long delay, we have a very long tail of PRs to deal with.

This won't push the release tags, as they are pushed manually via the release script. We'll merge this as is to move forward. Could you also please update the release script to make it complete?

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/2023-10-13-nix-team-meeting-minutes-94/34395/1

[baloo]

will do! Thank you for the merge!