pkg/config: use modern Go stdlib for sorting and string operations (#5210)

- slices.SortedFunc + maps.Values + cmp.Compare instead of manual
  map-to-slice collection + sort.Slice (source/aggregator.go)
- strings.CutSuffix instead of HasSuffix+TrimSuffix, and deduplicate
  error handling in BandwidthQuantity.UnmarshalString (types/types.go)

pkg/config/types/types.go

@@ -70,24 +70,18 @@ func (q *BandwidthQuantity) UnmarshalString(s string) error {
 		f    float64
 		err  error
 	)
-	switch {
-	case strings.HasSuffix(s, "MB"):
+	if fstr, ok := strings.CutSuffix(s, "MB"); ok {
 		base = MB
-		fstr := strings.TrimSuffix(s, "MB")
 		f, err = strconv.ParseFloat(fstr, 64)
-		if err != nil {
-			return err
-		}
-	case strings.HasSuffix(s, "KB"):
+	} else if fstr, ok := strings.CutSuffix(s, "KB"); ok {
 		base = KB
-		fstr := strings.TrimSuffix(s, "KB")
 		f, err = strconv.ParseFloat(fstr, 64)
-		if err != nil {
-			return err
-		}
-	default:
+	} else {
 		return errors.New("unit not support")
 	}
+	if err != nil {
+		return err
+	}
 
 	q.s = s
 	q.i = int64(f * float64(base))

pkg/config/types/types_test.go

@@ -39,6 +39,31 @@ func TestBandwidthQuantity(t *testing.T) {
 	require.Equal(`{"b":"1KB","int":5}`, string(buf))
 }
 
+func TestBandwidthQuantity_MB(t *testing.T) {
+	require := require.New(t)
+
+	var w Wrap
+	err := json.Unmarshal([]byte(`{"b":"2MB","int":1}`), &w)
+	require.NoError(err)
+	require.EqualValues(2*MB, w.B.Bytes())
+
+	buf, err := json.Marshal(&w)
+	require.NoError(err)
+	require.Equal(`{"b":"2MB","int":1}`, string(buf))
+}
+
+func TestBandwidthQuantity_InvalidUnit(t *testing.T) {
+	var w Wrap
+	err := json.Unmarshal([]byte(`{"b":"1GB","int":1}`), &w)
+	require.Error(t, err)
+}
+
+func TestBandwidthQuantity_InvalidNumber(t *testing.T) {
+	var w Wrap
+	err := json.Unmarshal([]byte(`{"b":"abcKB","int":1}`), &w)
+	require.Error(t, err)
+}
+
 func TestPortsRangeSlice2String(t *testing.T) {
 	require := require.New(t)