write nixos-module for declaration of systemd service

flake.nix

@@ -10,8 +10,11 @@
     pkgs = nixpkgs.legacyPackages.${system};
 
     reactApp = pkgs.buildNpmPackage {
-      name = "react frontend";
+      name = "React Frontend";
       version = "0.1.0";
+      src = "./.";
+
+      npmDepsHash = "";
 
       # TODO: Configure npm building of frontend
 
@@ -20,7 +23,67 @@
     nixosModule = {config, lib, pkgs, ...}:
       let opts = config.services.blog-service; in
     {
-      # TODO: Write out options for frontend service (port hosting, nginx, backend ports?)
+      enableFrontend = lib.mkEnableOption "Enable Frontend of blog";
+
+      port = lib.mkOption {
+        type = lib.types.port;
+        description = "Port to host frontend";
+      };
+
+      credentialsFile = lib.mkOption {
+        type = lib.types.path;
+        description = "File containing secret environment variables";
+      };
+
+      default-nginx = {
+        enableNginx = lib.mkEnableOption "Enable nginx reverse proxy";
+        domainName = lib.mkOption {
+          type = lib.types.string;
+          description = "Domain name to host service";
+        };
+      };
+
+      config = lib.mkIf opts.enableFrontend {
+        systemd.services.blog-service = {
+          description = "Frontend of self-hosted blog";
+          wantedby = ["multi-user.target"];
+          after = ["network.target"];
+
+          environment = {
+            PORT = toString opts.port;
+          };
+
+          serviceConfig = {
+            ExecStart = "${reactApp}/bin/blog-service";
+            Restart = "always";
+            Type = "simple";
+            DynamicUser = "yes";
+            WorkingDirectory = "${reactApp}";
+            EnvironmentFile = "${opts.credentialsFile}";
+          };
+        };
+
+        services.nginx = lib.mkIf opts.default-nginx.enableNginx {
+          enable = true;
+          virtualHosts."${opts.default-nginx.domainName}" = {
+            forceSSL = true;
+            useACMEHost = let
+              b = builtins;
+              s = lib.strings;
+              fl = s.splitString "." "${opts.default-nginx.domainName}";
+                in b.concatStringsSep "." [ (b.elemAt fl (b.length fl - 2)) (b.elemAt fl (b.length fl - 1)) ];
+            
+            locations."/" = {
+              proxyPass = "http://localhost:${toString opts.port}";
+            };
+          };
+        };
+
+        networking.firewall.allowedTCPPorts = lib.mkMerge [
+          (lib.mkIf opts.enableFrontend [ opts.port ])
+          (lib.mkIf opts.default-nginx.enableNginx [ 80 443 ])
+        ];
+      };
     };
 
   in {