[WIP] Try add blog as module to flake

flake.nix

@@ -34,5 +34,7 @@
             };
             defaultPackage = blog.english;
           }
-    );
+    ) // {
+      nixosModule = (import ./module.nix);
+    };
 }

module.nix

@@ -0,0 +1,60 @@
+{ lib, config, ... }:
+with lib;
+let
+  cfg = config.services.danilafe-blog;
+  sslForDomain = domain: (cfg.ssl == true) || (cfg.ssl."${domain}" or false);
+  anySsl = any (mapAttrsToList (domain: pkg: sslForDomain domain) cfg.domains);
+  virtualHost = domain: package: mkMerge [
+    {
+      services.nginx.virtualHosts."${domain}" = mkMerge [
+        {
+          root = package;
+        }
+        (mkIf (sslForDomain domain) {
+          addSSL = true;
+          enableACME = true;
+          acmeRoot = cfg.challengePath;
+        })
+      ];
+    }
+    (mkIf (sslForDomain domain) {
+      # Workaround for new configuration setting all of /var to be readonly.
+      # See https://github.com/NixOS/nixpkgs/issues/139310
+      systemd.services."acme-${cfg.domain}".serviceConfig = {
+        ReadWritePaths = [ cfg.challengePath ];
+      };
+    })
+  ];
+  virtualHosts = mapAttrsToList virtualHost cfg.domains;
+in
+  {
+    options.services.danilafe-blog = {
+      enable = mkEnableOption "Daniel's blog service";
+      ssl = mkOption {
+        type = types.either types.bool (types.attrsOf types.bool);
+        default = false;
+        description = "Enable SSL and ACME for all or some domains.";
+      };
+      domains = mkOption {
+        type = types.attrsOf types.package;
+        description = "Attribute set where keys are domains and values are packages to host there.";
+      };
+      challengePath = mkOption {
+        type = types.str;
+        description = "The location for ACME challenges";
+      };
+    };
+
+    config = mkIf cfg.enable (mkMerge (virtualHosts ++ [
+      {
+        # Always enable nginx.
+        services.nginx.enable = true;
+        services.nginx.recommendedGzipSettings = true;
+      }
+      (mkIf anySsl {
+        # If any domain uses SSL, enable ACME and accept terms.
+        security.acme.email = "danila.fedorin@gmail.com";
+        security.acme.acceptTerms = true;
+      })
+    ]));
+  }