make quantity flag work with pflag package

pkg/api/resource/quantity.go

@@ -386,6 +386,7 @@ type qFlag struct {
 	dest *Quantity
 }
 
+// Sets the value of the internal Quantity. (used by flag & pflag)
 func (qf qFlag) Set(val string) error {
 	q, err := ParseQuantity(val)
 	if err != nil {
@@ -396,10 +397,16 @@ func (qf qFlag) Set(val string) error {
 	return nil
 }
 
+// Converts the value of the internal Quantity to a string. (used by flag & pflag)
 func (qf qFlag) String() string {
 	return qf.dest.String()
 }
 
+// States the type of flag this is (Quantity). (used by pflag)
+func (qf qFlag) Type() string {
+	return "quantity"
+}
+
 // QuantityFlag is a helper that makes a quantity flag (using standard flag package).
 // Will panic if defaultValue is not a valid quantity.
 func QuantityFlag(flagName, defaultValue, description string) *Quantity {

pkg/api/resource/quantity_test.go

@@ -22,6 +22,7 @@ import (
 	"testing"
 
 	fuzz "github.com/google/gofuzz"
+	"github.com/spf13/pflag"
 	"speter.net/go/exp/math/dec/inf"
 )
 
@@ -487,3 +488,10 @@ func TestQFlagSet(t *testing.T) {
 		t.Errorf("Unexpected result %v != %v", e, a)
 	}
 }
+
+func TestQFlagIsPFlag(t *testing.T) {
+	var pfv pflag.Value = qFlag{}
+	if e, a := "quantity", pfv.Type(); e != a {
+		t.Errorf("Unexpected result %v != %v", e, a)
+	}
+}