nixos/grafana: listen on localhost by default (again)

nixos/doc/manual/from_md/release-notes/rl-2305.section.xml

@@ -339,6 +339,14 @@
           NixOS manual.
         </para>
       </listitem>
+      <listitem>
+        <para>
+          <literal>services.grafana</literal> listens only on localhost
+          by default again. This was changed to upstreams default of
+          <literal>0.0.0.0</literal> by accident in the freeform setting
+          conversion.
+        </para>
+      </listitem>
       <listitem>
         <para>
           A new <literal>virtualisation.rosetta</literal> module was

nixos/doc/manual/release-notes/rl-2305.section.md

@@ -95,6 +95,8 @@ In addition to numerous new and upgraded packages, this release has the followin
 
 - `nixos/lib/make-disk-image.nix` can now mutate EFI variables, run user-provided EFI firmware or variable templates. This is now extensively documented in the NixOS manual.
 
+- `services.grafana` listens only on localhost by default again. This was changed to upstreams default of `0.0.0.0` by accident in the freeform setting conversion.
+
 - A new `virtualisation.rosetta` module was added to allow running `x86_64` binaries through [Rosetta](https://developer.apple.com/documentation/apple-silicon/about-the-rosetta-translation-environment) inside virtualised NixOS guests on Apple silicon. This feature works by default with the [UTM](https://docs.getutm.app/) virtualisation [package](https://search.nixos.org/packages?channel=unstable&show=utm&from=0&size=1&sort=relevance&type=packages&query=utm).
 
 - The new option `users.motdFile` allows configuring a Message Of The Day that can be updated dynamically.

nixos/modules/services/monitoring/grafana.nix

@@ -364,9 +364,15 @@ in {
             };
 
             http_addr = mkOption {
-              description = lib.mdDoc "Listening address.";
-              default = "";
               type = types.str;
+              default = "127.0.0.1";
+              description = lib.mdDoc ''
+                Listening address.
+
+                ::: {.note}
+                This setting intentionally varies from upstream's default to be a bit more secure by default.
+                :::
+              '';
             };
 
             http_port = mkOption {