nixos/dendrite: remove

[mjlbach]

Motivation for this change

There are some usability problems around the module re: dynamic user's ability to access protected files (you currently need to copy these into the persistent state directory). I said I'd fix it before the 21.05 branch off, but I could not due to some issues I ran into with systemd.

@dotlambda I'm not going to be able to get LoadCredential working before systemd 248 likely. There are other workarounds to improve the ergonomics of DynamicUser with the TLS/federation keys but not sure if we could get those in before 21.05. I can make a PR un-reverting this which includes the tests/etc.

Things done

Remove dendrite, dendrite module, dendrite tests.

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

[dotlambda]

That's sad :(
Did you come across any particular issues when trying systemd credentials?

I think there's no need to remove the package, just the module.

What's @NixOS/nixos-release-managers opinion on this? The rationale is that shipping a broken module is bad because we might have to introduce breaking changes to fix it. That said, the module is working except for tlsKey and tlsCert options.

[dotlambda]

@mjlbach Please add a short rationale to the commit message.

[mjlbach]

@dotlambda you should write whatever rationale you want here, and I'll add it to the commit message.

Re: LoadCredential, I'm running into the same issue as @happysalada does here systemd/systemd#19604

[mohe2015]

I'm not using this currently but what about only removing on the release branch (which is not created yet afaik) and keeping in unstable?

[dotlambda]

I'm not using this currently but what about only removing on the release branch (which is not created yet afaik) and keeping in unstable?

That sounds like a good option.

@dotlambda you should write whatever rationale you want here, and I'll add it to the commit message.

I guess something like "The options tlsKey and tlsCert are broken and fixing them might require breaking changes. Thus the module should not be included in a stable release."

Re: LoadCredential, I'm running into the same issue as @happysalada does here systemd/systemd#19604

You could try rebasing your changes on #123476 and see if that works.

[mjlbach]

That sounds like a good option.

Ok! I'll file this same PR with that message into 21.05 after branch-off.

Re: systemd 248, sg, I will try this weekend to get everything running and if it works we can fix the module on nixpkgs-unstable.

[mohe2015]

@mjlbach branchoff has happened so you may want to do this now.

[mjlbach]

Just did :)