Add Last Update widget to Homepage via record-update script

record-update parses nvd diff after switch and writes latest.json;
Homepage polls a local-only nginx listener and renders date/changes/
closure/kernel via a customapi widget.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

common.nix

@@ -74,7 +74,7 @@
 
   # Shell aliases (work in both bash and fish)
   environment.shellAliases = {
-    update = "bash -c 'OLD_SYSTEM=$(readlink /run/current-system) && sudo nixos-rebuild build $@ --flake github:ediblerope/nixos-config && sudo nixos-rebuild switch $@ --flake github:ediblerope/nixos-config && nvd diff $OLD_SYSTEM /run/current-system && command -v matugen &>/dev/null && matugen image ~/.local/share/backgrounds/wallpaper.png --source-color-index 0 -m dark || true' --";
+    update = "bash -c 'OLD_SYSTEM=$(readlink /run/current-system) && sudo nixos-rebuild build $@ --flake github:ediblerope/nixos-config && sudo nixos-rebuild switch $@ --flake github:ediblerope/nixos-config && nvd diff $OLD_SYSTEM /run/current-system && (command -v record-update &>/dev/null && record-update $OLD_SYSTEM /run/current-system || true) && command -v matugen &>/dev/null && matugen image ~/.local/share/backgrounds/wallpaper.png --source-color-index 0 -m dark || true' --";
     clean = "sudo nix-collect-garbage -d";
     ll = "ls -alh";
     clear = "command clear";

hosts/FredOS-Mediaserver.nix

@@ -22,6 +22,10 @@
         export PATH="${pkgs.jellyfin-ffmpeg}/bin:${pkgs.coreutils}/bin:${pkgs.findutils}/bin:${pkgs.gnugrep}/bin:${pkgs.gawk}/bin:${pkgs.bc}/bin:${pkgs.curl}/bin:$PATH"
         exec ${pkgs.bash}/bin/bash ${../scripts/transcode-hevc.sh} "$@"
       '')
+      (pkgs.writeShellScriptBin "record-update" ''
+        export PATH="${pkgs.nvd}/bin:${pkgs.coreutils}/bin:${pkgs.gnugrep}/bin:${pkgs.gnused}/bin:$PATH"
+        exec ${pkgs.bash}/bin/bash ${../scripts/record-update.sh} "$@"
+      '')
     ];
 
     # Basic networking

scripts/record-update.sh

@@ -0,0 +1,41 @@
+#!/usr/bin/env bash
+# Parse `nvd diff <old> <new>` output and write a JSON summary
+# consumed by the Homepage dashboard's customapi widget.
+set -euo pipefail
+
+OLD="${1:-}"
+NEW="${2:-/run/current-system}"
+OUT_DIR="/var/lib/homepage-updates"
+OUT_FILE="$OUT_DIR/latest.json"
+
+if [ -z "$OLD" ]; then
+  echo "usage: record-update <old-system> [new-system]" >&2
+  exit 1
+fi
+
+mkdir -p "$OUT_DIR"
+
+DIFF=$(nvd diff "$OLD" "$NEW" 2>&1 || true)
+
+CHANGES=$(printf '%s\n' "$DIFF" | grep -cE '^\[[UAR][.*]\]' || true)
+CLOSURE=$(printf '%s\n' "$DIFF" | grep -oE 'disk usage [+-][0-9.]+[A-Za-z]*B?' | head -1 | sed 's/disk usage //')
+CLOSURE="${CLOSURE:-+0B}"
+
+KERNEL=$(uname -r)
+DATE=$(date '+%Y-%m-%d %H:%M')
+
+if [ "$CHANGES" = "0" ]; then
+  LABEL="No changes"
+else
+  LABEL="$CHANGES package changes"
+fi
+
+cat > "$OUT_FILE.tmp" <<EOF
+{
+  "date": "$DATE",
+  "changes": "$LABEL",
+  "closure": "$CLOSURE",
+  "kernel": "$KERNEL"
+}
+EOF
+mv "$OUT_FILE.tmp" "$OUT_FILE"

services/homepage.nix

@@ -65,6 +65,7 @@ in
     systemd.tmpfiles.rules = [
       "d /var/lib/homepage-custom-css 0755 fred users -"
       "f /var/lib/homepage-custom-css/custom.css 0644 fred users -"
+      "d /var/lib/homepage-updates 0755 fred users -"
     ];
 
     systemd.services.homepage-dashboard.serviceConfig.BindPaths = [
@@ -257,6 +258,25 @@ in
                 icon = "go2rtc.png";
               };
             }
+            {
+              "Last Update" = {
+                description = "Most recent nixos-rebuild switch";
+                icon = "mdi-history";
+                widget = {
+                  type = "customapi";
+                  url = "http://127.0.0.1:8083/latest.json";
+                  refreshInterval = 60000;
+                  method = "GET";
+                  display = "list";
+                  mappings = [
+                    { field = "date";    label = "Date"; }
+                    { field = "changes"; label = "Changes"; }
+                    { field = "closure"; label = "Closure"; }
+                    { field = "kernel";  label = "Kernel"; }
+                  ];
+                };
+              };
+            }
           ];
         }
       ];

services/nginx.nix

@@ -107,6 +107,16 @@ in
         # --- Protected by Authelia ---
         "camera.nordhammer.it"   = protectedProxy 1984;
         "homepage.nordhammer.it" = protectedProxy 8082;
+
+        # --- Local-only: serves update history JSON to Homepage's customapi widget ---
+        "homepage-updates.local" = {
+          listen = [ { addr = "127.0.0.1"; port = 8083; } ];
+          locations."/".root = "/var/lib/homepage-updates";
+          extraConfig = ''
+            default_type application/json;
+            add_header Access-Control-Allow-Origin *;
+          '';
+        };
       };
     };