bekkalokk: Automatically unpack pvv-nettsiden/gallery and generate thumbnails

hosts/bekkalokk/services/website/fetch-gallery.nix

@@ -1,5 +1,61 @@
 { pkgs, lib, config, ... }:
-{
+let
+  galleryDir = config.services.pvv-nettsiden.settings.GALLERY.DIR;
+  transferDir = "${config.services.pvv-nettsiden.settings.GALLERY.DIR}-transfer";
+in {
+  users.users.${config.services.pvv-nettsiden.user} = {
+    useDefaultShell = true;
 
+    # This is pushed from microbel:/var/www/www-gallery/build-gallery.sh
+    openssh.authorizedKeys.keys = [
+    ''command="${pkgs.rrsync}/bin/rrsync -wo ${transferDir}",restrict,no-agent-forwarding,no-port-forwarding,no-pty,no-X11-forwarding ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIIjHhC2dikhWs/gG+m7qP1eSohWzTehn4ToNzDSOImyR gallery-publish''
+    ];
+  };
+
+  systemd.paths.pvv-nettsiden-gallery-update = {
+    wantedBy = [ "multi-user.target" ];
+    pathConfig = {
+      PathChanged = "${transferDir}/gallery.tar.gz";
+      Unit = "pvv-nettsiden-gallery-update.service";
+      MakeDirectory = true;
+    };
+  };
+
+  systemd.services.pvv-nettsiden-gallery-update = {
+    path = with pkgs; [ imagemagick gnutar gzip ];
+
+    script = ''
+      tar ${lib.cli.toGNUCommandLineShell {} {
+        extract = true;
+        file = "${transferDir}/gallery.tar.gz";
+        directory = ".";
+      }}
+
+      # Delete files and directories that exists in the gallery that don't exist in the tarball
+      filesToRemove=$(uniq -u <(sort <(find . -not -path "./.thumbnails*") <(tar -tf ${transferDir}/gallery.tar.gz | sed 's|/$||')))
+      while IFS= read fname; do
+        rm -f $fname ||:
+        rm -f .thumbnails/$fname.png ||:
+      done <<< "$filesToRemove"
+
+      find . -type d -empty -delete
+
+      mkdir -p .thumbnails
+      images=$(find . -type f -not -path "./.thumbnails*")
+
+      while IFS= read fname; do
+        [ -f ".thumbnails/$fname.png" ] && continue ||:
+
+        echo "Creating thumbnail for $fname"
+        mkdir -p $(dirname ".thumbnails/$fname")
+        convert -define jpeg:size=200x200 "$fname" -thumbnail 500 ".thumbnails/$fname.png" ||:
+      done <<< "$images"
+    '';
+
+    serviceConfig = {
+      WorkingDirectory = galleryDir;
+      User = config.services.pvv-nettsiden.user;
+      Group = config.services.pvv-nettsiden.group;
+    };
+  };
 }
-