Don't crash when using KEYS in sidetiq/web.

lib/sidetiq/views/locks.erb

@@ -13,6 +13,7 @@
     <%= erb File.read(File.join(view_path, '_home_nav.erb')) %>
 
     <div class="col-md-9">
+      <% if @locks_available %>
       <% if @locks.length > 0 %>
       <table class="table table-striped table-bordered table-white table-sidetiq">
         <thead>
@@ -44,7 +45,9 @@
       <% else %>
       <div class="alert alert-success">No locks set.</div>
       <% end %>
-    </div>
+      <% else %>
+      <div class="alert alert-danger">KEYS command is disabled in your redis instance, lock information is not available.</div>
+      <% end %>
   </div>
 </div>
 

lib/sidetiq/web.rb

@@ -13,7 +13,12 @@ module Sidetiq
       end
 
       app.get "/sidetiq/locks" do
-        @locks = Sidetiq::Lock::Redis.all.map(&:meta_data)
+        begin
+          @locks = Sidetiq::Lock::Redis.all.map(&:meta_data)
+          @locks_available = true
+        rescue Redis::CommandError
+          @locks_available = false
+        end
 
         erb File.read(File.join(VIEWS, 'locks.erb')), locals: {view_path: VIEWS}
       end