F - oldest first sorting

reaper/options.go

@@ -6,6 +6,7 @@ import (
 	v1 "k8s.io/api/core/v1"
 	"math/rand"
 	"os"
+	"sort"
 	"strconv"
 	"strings"
 	"time"
@@ -178,6 +179,18 @@ func podSortingStrategy() (func([]v1.Pod), error) {
 		return func(pods []v1.Pod) {
 			rand.Shuffle(len(pods), func(i, j int) { pods[i], pods[j] = pods[j], pods[i] })
 		}, nil
+	case "oldest-first":
+		return func(pods []v1.Pod) {
+			sort.Slice(pods, func(i, j int) bool {
+				if pods[i].Status.StartTime == nil {
+					return false
+				}
+				if pods[j].Status.StartTime == nil {
+					return true
+				}
+				return pods[i].Status.StartTime.Unix() < pods[j].Status.StartTime.Unix()
+			})
+		}, nil
 	default:
 		return nil, errors.New("unknown pod sorting strategy")
 	}

reaper/options_test.go

@@ -19,15 +19,32 @@ func init() {
 	logrus.SetOutput(ioutil.Discard)
 }
 
+func epocPlus(duration time.Duration) *metav1.Time {
+	t := metav1.NewTime(time.Unix(0, 0).Add(duration))
+	return &t
+}
 func testPodList() []v1.Pod {
 	return []v1.Pod{
 		{
+			Status: v1.PodStatus{
+				StartTime: epocPlus(2 * time.Minute),
+			},
 			ObjectMeta: metav1.ObjectMeta{
 				Name:        "bearded-dragon",
 				Annotations: map[string]string{"example/key": "lizard"},
 			},
 		},
 		{
+			Status: v1.PodStatus{},
+			ObjectMeta: metav1.ObjectMeta{
+				Name:        "nil-start-time",
+				Annotations: map[string]string{"example/key": "lizard"},
+			},
+		},
+		{
+			Status: v1.PodStatus{
+				StartTime: epocPlus(1 * time.Minute),
+			},
 			ObjectMeta: metav1.ObjectMeta{
 				Name:        "corgi",
 				Annotations: map[string]string{"example/key": "not-lizard"},
@@ -297,6 +314,18 @@ func TestOptions(t *testing.T) {
 			sorter(subject)
 			assert.NotEqual(t, testPodList(), subject)
 		})
+		t.Run("oldest-first", func(t *testing.T) {
+			os.Clearenv()
+			os.Setenv(envPodSortingStrategy, "oldest-first")
+			sorter, err := podSortingStrategy()
+			assert.NotNil(t, sorter)
+			assert.NoError(t, err)
+			subject := testPodList()
+			sorter(subject)
+			assert.Equal(t, "corgi", subject[0].ObjectMeta.Name)
+			assert.Equal(t, "bearded-dragon", subject[1].ObjectMeta.Name)
+			assert.Equal(t, "nil-start-time", subject[2].ObjectMeta.Name)
+		})
 	})
 }