host: add deault implementation for system.build.isoImage target (per…

[blaggacao]

… host)

This is a more generic implementation to ISO builds, similar to what nixpkgs/flake.nix does with lib.nixosSystem for VMs.

In a follow up PR, I'll implement netboot and sd card flashing (in principle)
as prototyped here: numtide/flake-utils@d1ff2f0

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Looks promising:

$ nix build .#nixosConfigurations.NixOS.config.system.build.iso
$ nix build .#nixosConfigurations.ci.config.system.build.iso
$ ls result/iso
nixos-NixOS-20.09pre-git-x86_64-linux.iso
# ... still waiting for results from ci build
# ... wait a minute: wouldn't this be a strategy for ci targets, too? (it looks like so) ... going to stop it

The wireless conflict (2nd commit) comes from the installation device profile

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EDIT: I fixed flk iso NixOS in latest force-push

[blaggacao]

preview idea for possible sd + netboot support: blaggacao#1

[nrdxp]

This looks great. Anything else you want to implement, or is it ready for merge?

[blaggacao]

This is ready for merge, going forward you might put a close eye on what would be necessary here: https://github.com/nrdxp/nixflk/pull/102/files#diff-9e2394d5d965447692e8b09d0235b8fdd8426071c2537d0e4a7e4786d9fcf97eR32-R33

Please also build on your machine to check if everything works (it worked over here).

I'm still fighting with sd-images for similar reasons (option overrides) on blaggacao#1 (while netboot seems good).

I might open another PR with netboot support, soonish though.

[nrdxp]

I'll give it a test drive and see if everything works out. If so I'll go ahead and merge.

[nrdxp]

Basically just wondering if we can break out the logic in lib/default.nix instead of clutter the head of hosts/default.nix. Other than that, everything seems to work wonderfully.

[blaggacao]

For future reference / inspiration: https://github.com/nix-community/nixos-generators, specifically: nix-community/nixos-generators#85

[nrdxp]

Oh, also please update the README.md to reflect the new changes.

[blaggacao]

Can you review again:

• Readme updated (force push)
• moved to ./lib

[nrdxp]

Sent a PR with some small style fixups to keep the line limit under control. Other than that, this looks ready to merge!