feat(customresourcestate): Support percentages

Author: mrueg

docs/customresourcestate-metrics.md

@@ -255,6 +255,7 @@ Supported types are:
   * `"true"` and `"yes"` are mapped to `1.0` and `"false"` and `"no"` are mapped to `0.0` (all case insensitive)
   * RFC3339 times are parsed to float timestamp  
   * Quantities like "250m" or "512Gi" are parsed to float using https://github.com/kubernetes/apimachinery/blob/master/pkg/api/resource/quantity.go
+  * Percentages ending with a "%" are parsed to float
   * finally the string is parsed to float using https://pkg.go.dev/strconv#ParseFloat which should support all common number formats. If that fails an error is yielded
 
 ##### Example for status conditions on Kubernetes Controllers

pkg/customresourcestate/registry_factory.go

@@ -27,6 +27,7 @@ import (
 
 	"k8s.io/apimachinery/pkg/api/resource"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/util/validation"
 	"k8s.io/klog/v2"
 
 	"k8s.io/kube-state-metrics/v2/pkg/metric"
@@ -707,6 +708,12 @@ func toFloat64(value interface{}, nilIsZero bool) (float64, error) {
 		if t, e := resource.ParseQuantity(value.(string)); e == nil {
 			return t.AsApproximateFloat64(), nil
 		}
+		// The string contains a percentage with a suffix "%"
+		if e := validation.IsValidPercent(value.(string)); len(e) == 0 {
+			t, e := strconv.ParseFloat(strings.TrimRight(value.(string), "%"), 64)
+			return t / 100, e
+		}
+
 		return strconv.ParseFloat(value.(string), 64)
 	case byte:
 		v = float64(vv)

pkg/customresourcestate/registry_factory_test.go

@@ -67,6 +67,7 @@ func init() {
 			"uptime":            43.21,
 			"quantity_milli":    "250m",
 			"quantity_binarySI": "5Gi",
+			"percentage":        "28%",
 			"condition_values": Array{
 				Obj{
 					"name":  "a",
@@ -97,6 +98,7 @@ func init() {
 				"qux": "quxx",
 				"bar": "baz",
 			},
+			"percentage":        "39%",
 			"creationTimestamp": "2022-06-28T00:00:00Z",
 		},
 	})
@@ -241,6 +243,24 @@ func Test_values(t *testing.T) {
 		}, wantResult: []eachValue{
 			newEachValue(t, 5.36870912e+09),
 		}},
+		{name: "percentage", each: &compiledGauge{
+			compiledCommon: compiledCommon{
+				path: mustCompilePath(t, "status", "percentage"),
+			},
+		}, wantResult: []eachValue{
+			newEachValue(t, 0.28),
+		}},
+		{name: "path-relative valueFrom percentage", each: &compiledGauge{
+			compiledCommon: compiledCommon{
+				path: mustCompilePath(t, "metadata"),
+				labelFromPath: map[string]valuePath{
+					"name": mustCompilePath(t, "name"),
+				},
+			},
+			ValueFrom: mustCompilePath(t, "percentage"),
+		}, wantResult: []eachValue{
+			newEachValue(t, 0.39, "name", "foo"),
+		}},
 		{name: "boolean_string", each: &compiledGauge{
 			compiledCommon: compiledCommon{
 				path: mustCompilePath(t, "spec", "paused"),