using functional interfaces for future cleaners and validators of other record types

Signed-off-by: hfuss <[email protected]>

Author: onelapahead

endpoint/endpoint.go

@@ -255,15 +255,17 @@ func NewEndpoint(dnsName, recordType string, targets ...string) *Endpoint {
 // NewEndpointWithTTL initialization method to be used to create an endpoint with a TTL struct
 func NewEndpointWithTTL(dnsName, recordType string, ttl TTL, targets ...string) *Endpoint {
 	cleanTargets := make([]string, len(targets))
-	for idx, target := range targets {
+	var cleaner endpointTargetCleaner
+	switch recordType {
+	case RecordTypeTXT, RecordTypeNAPTR:
 		// Only trim trailing dots for domain name record types, not for TXT or NAPTR records
 		// TXT records can contain arbitrary text including multiple dots
-		switch recordType {
-		case RecordTypeTXT, RecordTypeNAPTR:
-			cleanTargets[idx] = target
-		default:
-			cleanTargets[idx] = strings.TrimSuffix(target, ".")
-		}
+		cleaner = &arbitraryTextEndpointTargetCleaner{}
+	default:
+		cleaner = &defaultEndpointTargetCleaner{}
+	}
+	for idx, target := range targets {
+		cleanTargets[idx] = cleaner.Clean(target)
 	}
 
 	for label := range strings.SplitSeq(dnsName, ".") {

endpoint/target_cleaner.go

@@ -0,0 +1,41 @@
+/*
+Copyright 2017 The Kubernetes 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 endpoint
+
+import "strings"
+
+// endpointTargetCleaner is essentially a function that cleans a target string for a given record.
+// It returns the cleaned target string, which is used to create an endpoint. Different record types have different cleaning rules.
+type endpointTargetCleaner interface {
+	Clean(target string) string
+}
+
+// defaultEndpointTargetCleaner is a function that cleans a target string for a given record, trimming trailing dots which are not allowed
+// for most record types.
+type defaultEndpointTargetCleaner struct{}
+
+func (v *defaultEndpointTargetCleaner) Clean(target string) string {
+	return strings.TrimSuffix(target, ".")
+}
+
+// arbitraryTextEndpointTargetCleaner is a function that cleans a target string for a given record, preserving arbitrary text including trailing dots.
+// This is used for TXT and NAPTR records.
+type arbitraryTextEndpointTargetCleaner struct{}
+
+func (v *arbitraryTextEndpointTargetCleaner) Clean(target string) string {
+	return target
+}

endpoint/target_cleaner_test.go

@@ -0,0 +1,35 @@
+/*
+Copyright 2017 The Kubernetes 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 endpoint
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDefaultEndpointTargetCleaner(t *testing.T) {
+	cleaner := &defaultEndpointTargetCleaner{}
+	assert.Equal(t, "example.com", cleaner.Clean("example.com."))
+	assert.Equal(t, "example.com", cleaner.Clean("example.com"))
+}
+
+func TestArbitraryTextEndpointTargetCleaner(t *testing.T) {
+	cleaner := &arbitraryTextEndpointTargetCleaner{}
+	assert.Equal(t, "example.com.", cleaner.Clean("example.com."))
+	assert.Equal(t, "example.com", cleaner.Clean("example.com"))
+}

source/crd.go

@@ -185,13 +185,18 @@ func (cs *crdSource) Endpoints(ctx context.Context) ([]*endpoint.Endpoint, error
 			if (ep.RecordType == endpoint.RecordTypeCNAME || ep.RecordType == endpoint.RecordTypeA || ep.RecordType == endpoint.RecordTypeAAAA) && len(ep.Targets) < 1 {
 				log.Debugf("Endpoint %s with DNSName %s has an empty list of targets, allowing it to pass through for default-targets processing", dnsEndpoint.Name, ep.DNSName)
 			}
-			isNAPTR := ep.RecordType == endpoint.RecordTypeNAPTR
-			isTXT := ep.RecordType == endpoint.RecordTypeTXT
+
+			var validator endpointTargetValidator
+			switch ep.RecordType {
+			case endpoint.RecordTypeTXT, endpoint.RecordTypeNAPTR:
+				validator = &arbitraryTextEndpointTargetValidator{}
+			default:
+				validator = &defaultEndpointTargetValidator{}
+			}
+
 			illegalTarget := false
 			for _, target := range ep.Targets {
-				hasDot := strings.HasSuffix(target, ".")
-				// Skip dot validation for TXT records as they can contain arbitrary text
-				if !isTXT && ((isNAPTR && !hasDot) || (!isNAPTR && hasDot)) {
+				if validator.IsInvalid(target) {
 					illegalTarget = true
 					break
 				}

source/endpoints.go

@@ -15,6 +15,7 @@ package source
 
 import (
 	"fmt"
+	"strings"
 
 	"k8s.io/apimachinery/pkg/labels"
 	coreinformers "k8s.io/client-go/informers/core/v1"
@@ -110,3 +111,25 @@ func EndpointTargetsFromServices(svcInformer coreinformers.ServiceInformer, name
 	}
 	return endpoint.NewTargets(targets...), nil
 }
+
+// endpointTargetValidator is a function that validates a target string for a given record type
+// It returns true if the target is _invalid_, and false if it is valid.
+type endpointTargetValidator interface {
+	IsInvalid(target string) bool
+}
+
+// defaultEndpointTargetValidator is a function that validates a target string for a given record type, trimming trailing dots which are not allowed
+// for most record types.
+type defaultEndpointTargetValidator struct{}
+
+func (v *defaultEndpointTargetValidator) IsInvalid(target string) bool {
+	return strings.HasSuffix(target, ".")
+}
+
+// arbitraryTextTargetValidator is a function that validates a target string for a given record type, allowing arbitrary text including trailing dots.
+// This is used for TXT and NAPTR records.
+type arbitraryTextEndpointTargetValidator struct{}
+
+func (v *arbitraryTextEndpointTargetValidator) IsInvalid(target string) bool {
+	return false
+}

source/endpoints_test.go

@@ -344,3 +344,15 @@ func TestEndpointTargetsFromServicesWithFixtures(t *testing.T) {
 	assert.NoError(t, err)
 	assert.Equal(t, 2, targets.Len())
 }
+
+func TestDefaultEndpointTargetValidator(t *testing.T) {
+	validator := &defaultEndpointTargetValidator{}
+	assert.True(t, validator.IsInvalid("example.com."))
+	assert.False(t, validator.IsInvalid("example.com"))
+}
+
+func TestArbitraryTextEndpointTargetValidator(t *testing.T) {
+	validator := &arbitraryTextEndpointTargetValidator{}
+	assert.False(t, validator.IsInvalid("example.com."))
+	assert.False(t, validator.IsInvalid("example.com"))
+}