kubernetes: Ignore internal K8S annotations

builtin/providers/kubernetes/structures.go

@@ -2,6 +2,7 @@ package kubernetes
 
 import (
 	"fmt"
+	"net/url"
 	"strings"
 
 	"github.com/hashicorp/terraform/helper/schema"
@@ -65,7 +66,7 @@ func expandStringMap(m map[string]interface{}) map[string]string {
 
 func flattenMetadata(meta api.ObjectMeta) []map[string]interface{} {
 	m := make(map[string]interface{})
-	m["annotations"] = meta.Annotations
+	m["annotations"] = filterAnnotations(meta.Annotations)
 	m["generate_name"] = meta.GenerateName
 	m["labels"] = meta.Labels
 	m["name"] = meta.Name
@@ -80,3 +81,21 @@ func flattenMetadata(meta api.ObjectMeta) []map[string]interface{} {
 
 	return []map[string]interface{}{m}
 }
+
+func filterAnnotations(m map[string]string) map[string]string {
+	for k, _ := range m {
+		if isInternalAnnotationKey(k) {
+			delete(m, k)
+		}
+	}
+	return m
+}
+
+func isInternalAnnotationKey(annotationKey string) bool {
+	u, err := url.Parse("//" + annotationKey)
+	if err == nil && strings.HasSuffix(u.Hostname(), "kubernetes.io") {
+		return true
+	}
+
+	return false
+}

builtin/providers/kubernetes/structures_test.go

@@ -0,0 +1,32 @@
+package kubernetes
+
+import (
+	"fmt"
+	"testing"
+)
+
+func TestIsInternalAnnotationKey(t *testing.T) {
+	testCases := []struct {
+		Key      string
+		Expected bool
+	}{
+		{"", false},
+		{"anyKey", false},
+		{"any.hostname.io", false},
+		{"any.hostname.com/with/path", false},
+		{"any.kubernetes.io", true},
+		{"kubernetes.io", true},
+		{"pv.kubernetes.io/any/path", true},
+	}
+	for i, tc := range testCases {
+		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
+			isInternal := isInternalAnnotationKey(tc.Key)
+			if tc.Expected && isInternal != tc.Expected {
+				t.Fatalf("Expected %q to be internal", tc.Key)
+			}
+			if !tc.Expected && isInternal != tc.Expected {
+				t.Fatalf("Expected %q not to be internal", tc.Key)
+			}
+		})
+	}
+}