webring/host_config/default.nix

{ self, moduleWithSystem, ... }: {
  flake.nixosModules.code-server = moduleWithSystem (
    { ... }: # Note: only explicit parameters are passed to this.
    { pkgs, modulesPath, lib, ... }: {
      imports = [
        self.inputs.disko.nixosModules.disko
        (modulesPath + "/installer/scan/not-detected.nix")
        (modulesPath + "/profiles/headless.nix")
        (modulesPath + "/profiles/minimal.nix")
        (modulesPath + "/profiles/qemu-guest.nix")
        ./code_server_disk.nix
      ];

      system.stateVersion = "24.11";

      boot.kernelParams = [ "zfs.zfs_arc_max=536870912" ];
      boot.zfs.extraPools = [ "zroot" ];
      boot.initrd.postMountCommands = lib.mkAfter ''
        zfs rollback -r zroot/root@blank
      '';

      services.zfs.autoScrub.enable = true;
      boot.loader.grub = {
        enable = true;
        # No need to set devices, disko will add all devices that have an EF02 partition to the list already.
        # devices = [];
        efiSupport = true;
        efiInstallAsRemovable = true;
      };

      fileSystems = {
        "/var/lib/systemd" = {
          device = "/persisted/var/lib/systemd";
          options = [ "bind" ];
        };
        "/var/lib/forgejo" = {
          device = "/persisted/var/lib/forgejo";
          options = [ "bind" ];
        };
      };

      networking.hostId = "9f1dfd86"; # Required by ZFS.
      networking.useNetworkd = true;
      networking.firewall.logRefusedConnections = false;

      nix.gc.automatic = true;
      nix.gc.dates = "02:15";

      services.cloud-init = {
        enable = true;
        network.enable = true;
        settings = {
          datasource_list = [ "Hetzner" ];

          # The NixOS cloud-init settings declares the entire `system_info` with `lib.mkDefault`, so we need to copy the defaults from it here and make the changes we want to make.
          system_info = {
            paths = {
              cloud_dir = "/persisted/var/lib/cloud";
            };
            distro = "nixos";
            network = {
              renderers = [ "networkd" ];
              activators = [ "networkd" ];
            };
          };

          cloud_init_modules = [
            "migrator"
            "seed_random"
            "bootcmd"
          ];

          cloud_config_modules = [
            "ssh-import-id"
            "timezone"
            "runcmd"
            "ssh"
          ];

          cloud_final_modules = [
            "keys-to-console"
            "final-message"
            "power-state-change"
          ];
        };
      };

      services.openssh = {
        enable = true;
        hostKeys = [
          {
            path = "/persisted/etc/ssh/ssh_host_ed25519_key";
            type = "ed25519";
          }
        ];
        settings = {
          PasswordAuthentication = false;
        };
        extraConfig = ''
          HostCertificate /persisted/etc/ssh/ssh_host_ed25519_key-cert.pub
          TrustedUserCAKeys /persisted/etc/ssh/user_cas.pub
        '';
      };

      users.users.root = {
        home = lib.mkForce "/persisted/root";
      };

      networking.firewall.allowedTCPPorts = [ 80 443 ];
      # UDP allowed for HTTP/3.
      networking.firewall.allowedUDPPorts = [ 80 443 ];

      services.caddy = {
        enable = true;

        globalConfig = ''
          # Comment this if building the prod image. The following is only useful for testing.
          # local_certs
          skip_install_trust
        '';

        virtualHosts."code.akols.com".extraConfig = ''
          encode zstd gzip
          reverse_proxy http://127.0.0.1:3000
        '';
      };

      services.forgejo = {
        enable = true;

        package = pkgs.forgejo;
        lfs.enable = true;

        settings = {
          service = {
            DISABLE_REGISTRATION = true;
          };

          database = {
            SQLITE_JOURNAL_MODE = "WAL";
          };

          cache = {
            ADAPTER = "twoqueue";
            HOST = "{\"size\":100,\"recent_ratio\":0.25,\"ghost_ratio\":0.5}";
          };

          server = {
            HTTP_ADDR = "127.0.0.1";
            HTTP_PORT = 3000;
            DOMAIN = "code.akols.com";
            ROOT_URL = "https://code.akols.com";
          };

          session = {
            COOKIE_SECURE = true;
          };

          security = {
            LOGIN_REMEMBER_DAYS = 365;
          };
        };
      };
    }
  );
}