show RemoteVolumes/EcVolumes only if it is not empty

weed/server/volume_server_ui/templates.go

@@ -25,6 +25,7 @@ var funcMap = template.FuncMap{
 	"join":                 join,
 	"bytesToHumanReadable": util.BytesToHumanReadable,
 	"percentFrom":          percentFrom,
+	"isNotEmpty":           util.IsNotEmpty,
 }
 
 //go:embed volume.html

weed/server/volume_server_ui/volume.html

@@ -133,6 +133,7 @@
         </table>
     </div>
 
+    {{ if isNotEmpty .RemoteVolumes }}
     <div class="row">
         <h2>Remote Volumes</h2>
         <table class="table table-striped">
@@ -162,7 +163,9 @@
             </tbody>
         </table>
     </div>
+    {{ end }}
 
+    {{ if isNotEmpty .EcVolumes }}
     <div class="row">
         <h2>Erasure Coding Shards</h2>
         <table class="table table-striped">
@@ -188,7 +191,7 @@
             </tbody>
         </table>
     </div>
-
+    {{ end }}
 </div>
 </body>
 </html>

weed/util/reflect.go

@@ -0,0 +1,40 @@
+package util
+
+import "reflect"
+
+// IsNotEmpty returns true if the given value is not zero or empty.
+func IsNotEmpty(given interface{}) bool {
+	return !IsEmpty(given)
+}
+
+// IsEmpty returns true if the given value has the zero value for its type.
+func IsEmpty(given interface{}) bool {
+	g := reflect.ValueOf(given)
+	if !g.IsValid() {
+		return true
+	}
+
+	if g.Kind() == reflect.Ptr {
+		g = g.Elem()
+	}
+
+	// Basically adapted from text/template.isTrue
+	switch g.Kind() {
+	case reflect.Array, reflect.Slice, reflect.Map, reflect.String:
+		return g.Len() == 0
+	case reflect.Bool:
+		return !g.Bool()
+	case reflect.Complex64, reflect.Complex128:
+		return g.Complex() == 0
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return g.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+		return g.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return g.Float() == 0
+	case reflect.Struct:
+		return g.IsZero()
+	default:
+		return g.IsNil()
+	}
+}