support for plugins for navbar items

Netdisco/lib/App/Netdisco/Web.pm

@@ -13,7 +13,26 @@ use App::Netdisco::Web::AuthN;
 use App::Netdisco::Web::Search;
 use App::Netdisco::Web::Device;
 use App::Netdisco::Web::PortControl;
-use App::Netdisco::Web::Inventory;
+
+sub _load_web_plugins {
+  my $plugin_list = shift;
+
+  foreach my $plugin (@$plugin_list) {
+      $plugin = 'App::Netdisco::Web::Plugin::'. $plugin
+        unless $plugin =~ m/^\+/;
+      $plugin =~ s/^\+//;
+
+      eval "require $plugin";
+  }
+}
+
+if (setting('web_plugins') and ref [] eq ref setting('web_plugins')) {
+    _load_web_plugins( setting('web_plugins') );
+}
+
+if (setting('extra_web_plugins') and ref [] eq ref setting('extra_web_plugins')) {
+    _load_web_plugins( setting('extra_web_plugins') );
+}
 
 hook 'before_template' => sub {
     my $tokens = shift;

Netdisco/lib/App/Netdisco/Web/Plugin.pm

@@ -0,0 +1,27 @@
+package App::Netdisco::Web::Plugin;
+
+use Dancer ':syntax';
+use Dancer::Plugin;
+
+set('navbar_items' => []);
+
+register 'register_navbar_item' => sub {
+  my ($self, $config) = plugin_args(@_);
+
+  die "bad config to register_navbar_item\n"
+    unless length $config->{id}
+       and length $config->{path}
+       and length $config->{label};
+
+  foreach my $item (@{ setting('navbar_items') }) {
+      if ($item->{id} eq $config->{id}) {
+          $item = $config;
+          return;
+      }
+  }
+
+  push @{ setting('navbar_items') }, $config;
+};
+
+register_plugin;
+true;

Netdisco/lib/App/Netdisco/Web/Plugin/Inventory.pm

@@ -1,8 +1,16 @@
-package App::Netdisco::Web::Inventory;
+package App::Netdisco::Web::Plugin::Inventory;
 
 use Dancer ':syntax';
 use Dancer::Plugin::DBIC;
 
+use App::Netdisco::Web::Plugin;
+
+register_navbar_item({
+  id    => 'inventory',
+  path  => '/inventory',
+  label => 'Inventory',
+});
+
 get '/inventory' => sub {
     my $models = schema('netdisco')->resultset('Device')->get_models();
     my $releases = schema('netdisco')->resultset('Device')->get_releases();