add nostr-relay nixos module

modules/nixos/nostr-relay/default.nix

@@ -0,0 +1,57 @@
+{ config, lib, ... }:
+
+let
+  cfg = config.services.nostr-relay;
+  domain = config.networking.domain;
+  subdomain = cfg.reverseProxy.subdomain;
+  fqdn = if (cfg.reverseProxy.enable && subdomain != "") then "${subdomain}.${domain}" else domain;
+
+  inherit (lib)
+    mkDefault
+    mkIf
+    ;
+
+  inherit (lib.utils)
+    mkReverseProxyOption
+    ;
+in
+{
+  options.services.nostr-relay = {
+    reverseProxy = mkReverseProxyOption "Nostr Relay" "nostr";
+  };
+
+  config = mkIf cfg.enable {
+    services.nostr-rs-relay = {
+      settings = {
+        network = {
+          port = mkDefault 12849;
+          host = mkDefault (if cfg.reverseProxy.enable then "127.0.0.1" else "0.0.0.0");
+        };
+        limits = {
+          max_event_size = mkDefault 65536;
+          max_subscriptions = mkDefault 20;
+          max_filters = mkDefault 10;
+          max_subid_length = mkDefault 128;
+          max_event_tags = mkDefault 2000;
+          max_content_length = mkDefault 32768;
+        };
+        federation = {
+          enabled = mkDefault true;
+          max_message_size = mkDefault 1048576;
+        };
+        database = {
+          max_query_time_ms = mkDefault 5000;
+        };
+      };
+    };
+
+    services.nginx.virtualHosts = mkIf cfg.reverseProxy.enable {
+      "${fqdn}" = {
+        enableACME = cfg.reverseProxy.forceSSL;
+        forceSSL = cfg.reverseProxy.forceSSL;
+        locations."/".proxyPass =
+          "http://127.0.0.1:${toString config.services.nostr-rs-relay.settings.network.port}";
+      };
+    };
+  };
+}