nixos/httpd: always test the generated configuration

[zimbatm]

Motivation for this change

#34902 (comment)

not sure if that would work

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• 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 nox --run "nox-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)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.

---

[aanderse]

@zimbatm Currently apache is run as the root user so it can read ssl files which are root readable only which poses a problem for this PR (ie. files which won't be accessible when this apachectl command is run). Further to that the apache config file potentially depend on files/folders/users which don't exist yet (for example, your nixops server likely won't have a wwwrun user).

Very unfortunately I don't have any constructive ideas for this PR yet. I would love to see this problem solved, though.

[aanderse]

${httpd}/bin/apachectl configtest -f $out

[aanderse]

For future reference in case anyone sees this I'd like to correct my mistake I noticed. If specifying the config file you have to use ${httpd}/bin/httpd -t -f $out instead of the apachectl wrapper (which assumes a hard coded location for the config file).

[zimbatm]

good points. closing this for now

[grahamc]

This is a really big bummer, because this is such a nice idea.

[infinisil]

@volth How so?

[infinisil]

@volth

{
  nativeBuildInputs = [ httpd ];
  checkPhase = ''
    apachectl ...
  '';
}

should work though