Set appropriate delete option for server version

Annoyingly, delete options `OrphanDependents` and `PropagationPolicy`
are mutually exclusive.  This change compares the k8s server version
to see if the server is going to look for the newer PropagationPolicy.

Fixes a78be141 (aka PR #59)

cmd/delete.go

@@ -41,8 +41,6 @@ var deleteCmd = &cobra.Command{
 	Short: "Delete Kubernetes resources described in local config",
 	RunE: func(cmd *cobra.Command, args []string) error {
 		flags := cmd.Flags()
-		boolFalse := false
-		deletePolicyForeground := metav1.DeletePropagationForeground
 
 		gracePeriod, err := flags.GetInt64(flagGracePeriod)
 		if err != nil {
@@ -64,13 +62,22 @@ var deleteCmd = &cobra.Command{
 			return err
 		}
 
+		version, err := utils.FetchVersion(disco)
+		if err != nil {
+			return err
+		}
+
 		sort.Sort(sort.Reverse(utils.DependencyOrder(objs)))
 
-		deleteOpts := metav1.DeleteOptions{
+		deleteOpts := metav1.DeleteOptions{}
+		if version.Compare(1, 6) < 0 {
 			// 1.5.x option
-			OrphanDependents: &boolFalse,
+			boolFalse := false
+			deleteOpts.OrphanDependents = &boolFalse
+		} else {
 			// 1.6.x option (NB: Background is broken)
-			PropagationPolicy: &deletePolicyForeground,
+			fg := metav1.DeletePropagationForeground
+			deleteOpts.PropagationPolicy = &fg
 		}
 		if gracePeriod >= 0 {
 			deleteOpts.GracePeriodSeconds = &gracePeriod

utils/meta.go

+package utils
+
+import (
+	"fmt"
+	"strconv"
+
+	"k8s.io/apimachinery/pkg/version"
+	"k8s.io/client-go/discovery"
+)
+
+// ServerVersion captures k8s major.minor version in a parsed form
+type ServerVersion struct {
+	Major int
+	Minor int
+}
+
+// ParseVersion parses version.Info into a ServerVersion struct
+func ParseVersion(v *version.Info) (ret ServerVersion, err error) {
+	ret.Major, err = strconv.Atoi(v.Major)
+	if err != nil {
+		return
+	}
+	ret.Minor, err = strconv.Atoi(v.Minor)
+	if err != nil {
+		return
+	}
+	return
+}
+
+// FetchVersion fetches version information from discovery client, and parses
+func FetchVersion(v discovery.ServerVersionInterface) (ret ServerVersion, err error) {
+	version, err := v.ServerVersion()
+	if err != nil {
+		return ServerVersion{}, err
+	}
+	return ParseVersion(version)
+}
+
+// Compare returns -1/0/+1 iff v is less than / equal / greater than major.minor
+func (v ServerVersion) Compare(major, minor int) int {
+	a := v.Major
+	b := major
+
+	if a == b {
+		a = v.Minor
+		b = minor
+	}
+
+	var res int
+	if a > b {
+		res = 1
+	} else if a == b {
+		res = 0
+	} else {
+		res = -1
+	}
+	return res
+}
+
+func (v ServerVersion) String() string {
+	return fmt.Sprintf("%d.%d", v.Major, v.Minor)
+}

utils/meta_test.go

+package utils
+
+import (
+	"testing"
+
+	"k8s.io/apimachinery/pkg/version"
+)
+
+func TestParseVersion(t *testing.T) {
+	tests := []struct {
+		input    version.Info
+		expected ServerVersion
+		error    bool
+	}{
+		{
+			input:    version.Info{Major: "1", Minor: "6"},
+			expected: ServerVersion{Major: 1, Minor: 6},
+		},
+		{
+			input:    version.Info{Major: "1", Minor: "70"},
+			expected: ServerVersion{Major: 1, Minor: 70},
+		},
+		{
+			input: version.Info{Major: "1", Minor: "6x"},
+			error: true,
+		},
+	}
+
+	for _, test := range tests {
+		v, err := ParseVersion(&test.input)
+		if test.error {
+			if err == nil {
+				t.Errorf("test %s should have failed and did not", test.input)
+			}
+			continue
+		}
+		if err != nil {
+			t.Errorf("test %v failed: %v", test.input, err)
+			continue
+		}
+		if v != test.expected {
+			t.Errorf("Expected %v, got %v", test.expected, v)
+		}
+	}
+}
+
+func TestVersionCompare(t *testing.T) {
+	v := ServerVersion{Major: 2, Minor: 3}
+	tests := []struct {
+		major, minor, result int
+	}{
+		{major: 1, minor: 0, result: 1},
+		{major: 2, minor: 0, result: 1},
+		{major: 2, minor: 2, result: 1},
+		{major: 2, minor: 3, result: 0},
+		{major: 2, minor: 4, result: -1},
+		{major: 3, minor: 0, result: -1},
+	}
+	for _, test := range tests {
+		res := v.Compare(test.major, test.minor)
+		if res != test.result {
+			t.Errorf("%d.%d => Expected %d, got %d", test.major, test.minor, test.result, res)
+		}
+	}
+}