fix(efs): Ignore AWS system tags

Signed-off-by: Maximilian Blatt (external expert on behalf of DB Netz) <[email protected]>

pkg/controller/efs/utils/tags.go

@@ -18,6 +18,7 @@ package utils
 
 import (
 	"sort"
+	"strings"
 
 	svcsdk "github.com/aws/aws-sdk-go/service/efs"
 	"github.com/aws/aws-sdk-go/service/efs/efsiface"
@@ -98,6 +99,12 @@ func DiffTags(spec []*svcapitypes.Tag, current []*svcsdk.Tag) (addTags []*svcsdk
 	specMap := make(map[string]string, len(spec))
 	for _, t := range spec {
 		key := awsclient.StringValue(t.Key)
+
+		// Ignore "aws:" internal tags since they cannot be added or removed.
+		if strings.HasPrefix(key, "aws:") {
+			continue
+		}
+
 		val := awsclient.StringValue(t.Value)
 		specMap[key] = awsclient.StringValue(t.Value)
 
@@ -119,6 +126,12 @@ func DiffTags(spec []*svcapitypes.Tag, current []*svcsdk.Tag) (addTags []*svcsdk
 
 	for _, t := range current {
 		key := awsclient.StringValue(t.Key)
+
+		// Ignore "aws:" internal tags since they cannot be added or removed.
+		if strings.HasPrefix(key, "aws:") {
+			continue
+		}
+
 		if _, exists := specMap[key]; !exists {
 			removeTags = append(removeTags, awsclient.String(key))
 		}

pkg/controller/efs/utils/tags_test.go

@@ -0,0 +1,87 @@
+/*
+Copyright 2023 The Crossplane Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package utils
+
+import (
+	"testing"
+
+	svcsdk "github.com/aws/aws-sdk-go/service/efs"
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
+
+	svcapitypes "github.com/crossplane-contrib/provider-aws/apis/efs/v1alpha1"
+	awsclient "github.com/crossplane-contrib/provider-aws/pkg/clients"
+)
+
+func TestDiffTags(t *testing.T) {
+	type args struct {
+		spec    []*svcapitypes.Tag
+		current []*svcsdk.Tag
+	}
+	type want struct {
+		add    []*svcsdk.Tag
+		remove []*string
+	}
+
+	sdkTag := func(k, v string) *svcsdk.Tag {
+		return &svcsdk.Tag{Key: &k, Value: &v}
+	}
+
+	apiTag := func(k, v string) *svcapitypes.Tag {
+		return &svcapitypes.Tag{Key: &k, Value: &v}
+	}
+
+	cases := map[string]struct {
+		args args
+		want want
+	}{
+		"DoNotAddOrRemoveAWSystemTags": {
+			args: args{
+				spec: []*svcapitypes.Tag{
+					apiTag("foo", "bar"),
+					apiTag("testAdd", "val"),
+					apiTag("aws:some-system-tag", "enabled"),
+				},
+				current: []*svcsdk.Tag{
+					sdkTag("foo", "bar"),
+					sdkTag("testRemove", "val2"),
+					sdkTag("aws:elasticfilesystem:default-backup", "enabled"),
+				},
+			},
+			want: want{
+				add: []*svcsdk.Tag{
+					sdkTag("testAdd", "val"),
+				},
+				remove: []*string{
+					awsclient.String("testRemove"),
+				},
+			},
+		},
+	}
+
+	for name, tc := range cases {
+		t.Run(name, func(t *testing.T) {
+			add, remove := DiffTags(tc.args.spec, tc.args.current)
+			if diff := cmp.Diff(tc.want.add, add); diff != "" {
+				t.Errorf("add: -want, +got:\n%s", diff)
+			}
+			if diff := cmp.Diff(tc.want.remove, remove, cmpopts.SortSlices(func(a, b string) bool { return a > b })); diff != "" {
+				t.Errorf("remove: -want, +got:\n%s", diff)
+			}
+		})
+	}
+}