nixos/caddy: validate at build-time

[Stunkymonkey]

its nice to validate the config before reloading/restarting. same as nginx

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 25.05 Release Notes (or backporting 24.11 and 25.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

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[sephii]

We used to have this done in the build phase (which, in my opinion, is a better place to have it) before it was removed in 27b7132 (because the way it was done caused an import from derivation, but I think it can be easily adapted). How about doing the check in the build phase?

[Stunkymonkey]

@sephii doing this while building is an ever better idea. To catch the errors as early as possible. I am marking my MR as draft and ping you again if I have something. Thanks for the fast response.

[Stunkymonkey]

@sephii validating is a bit weird. caddy validate results into:

       > 2025/01/27 21:46:30.999 INFO    using config from file  {"file": "/nix/store/kz8lm6k81lsmziphpq0mfhdrv4nx049v-Caddyfile-formatted/Caddyfile"}
       > 2025/01/27 21:46:31.009 INFO    adapted config to JSON  {"adapter": "caddyfile"}
       > Error: setting up custom log 'log1': opening log writer using &logging.FileWriter{Filename:"/var/log/caddy/access-http:__localhost:8081.log", Mode:0x0, Roll:(*bool)(nil), RollSizeMB:0, RollCompress:(*bool)(nil), RollLocalTime:false, RollKeep:0, RollKeepDays:0}: mkdir /var: permission denied

it always wants to start and log the events, which can not work... so then i discovered caddy adapt, which validates the config itself. But somehow the json-test is not working any more, because of:

       last 1 log lines:
       > Error: Unexpected '{' on a new line; did you mean to place the '{' on the previous line?, at /nix/store/f2927acpq53srgy3sl722ssqj4yrn60k-caddy.json:10
       For full logs, run 'nix log /nix/store/b6ccpz1rfqvnj4ysdm4qmf5m4wb7r4vd-validate-caddy-config.drv'.

but the config is a valid json... not sure why caddy does this: https://github.com/caddyserver/caddy/blob/9996d6a70ba76a94dfc90548f25fbac0ce9da497/caddyconfig/caddyfile/parse.go#L656

[sephii]

Sorry I’m very busy these days. I’ll give it a look soon, maybe next week!

[Stunkymonkey]

@sephii no problem. thanks for reaching out.

[Stunkymonkey]

I am currently stuck here caddyserver/caddy#6788 (comment) .

[mohammed90]

caddy adapt, which validates the config itself

That's not what adapt does. It doesn't validate config. It only converts it from whatever format the specified adapter accepts to JSON. The validation is something separate.

[Stunkymonkey]

@sephii i finally managed to put something together. please take your time.