Filter out entire endpoint if it ends up without targets after filtering in targetFilterSource

source/targetfiltersource.go

@@ -19,6 +19,8 @@ package source
 import (
 	"context"
 
+	log "github.com/sirupsen/logrus"
+
 	"sigs.k8s.io/external-dns/endpoint"
 )
 
@@ -52,6 +54,12 @@ func (ms *targetFilterSource) Endpoints(ctx context.Context) ([]*endpoint.Endpoi
 			}
 		}
 
+		// If all targets are filtered out, skip the endpoint.
+		if len(filteredTargets) == 0 {
+			log.WithField("endpoint", ep).Debugf("Skipping endpoint because all targets were filtered out")
+			continue
+		}
+
 		ep.Targets = filteredTargets
 
 		result = append(result, ep)

source/targetfiltersource_test.go

@@ -0,0 +1,146 @@
+/*
+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 source
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"golang.org/x/net/context"
+
+	"sigs.k8s.io/external-dns/endpoint"
+)
+
+type mockTargetNetFilter struct {
+	targets map[string]bool
+}
+
+func NewMockTargetNetFilter(targets []string) endpoint.TargetFilterInterface {
+	targetMap := make(map[string]bool)
+	for _, target := range targets {
+		targetMap[target] = true
+	}
+	return &mockTargetNetFilter{targets: targetMap}
+}
+
+func (m *mockTargetNetFilter) Match(target string) bool {
+	return m.targets[target]
+}
+
+// echoSource is a Source that returns the endpoints passed in on creation.
+type echoSource struct {
+	endpoints []*endpoint.Endpoint
+}
+
+func (e *echoSource) AddEventHandler(ctx context.Context, handler func()) {
+}
+
+// Endpoints returns all of the endpoints passed in on creation
+func (e *echoSource) Endpoints(ctx context.Context) ([]*endpoint.Endpoint, error) {
+	return e.endpoints, nil
+}
+
+// NewEchoSource creates a new echoSource.
+func NewEchoSource(endpoints []*endpoint.Endpoint) Source {
+	return &echoSource{endpoints: endpoints}
+}
+
+func TestEchoSourceReturnGivenSources(t *testing.T) {
+	startEndpoints := []*endpoint.Endpoint{{
+		DNSName:    "foo.bar.com",
+		RecordType: "A",
+		Targets:    endpoint.Targets{"1.2.3.4"},
+		RecordTTL:  endpoint.TTL(300),
+		Labels:     endpoint.Labels{},
+	}}
+	e := NewEchoSource(startEndpoints)
+
+	endpoints, err := e.Endpoints(context.Background())
+	if err != nil {
+		t.Errorf("Expected no error but got %s", err.Error())
+	}
+
+	for i, endpoint := range endpoints {
+		if endpoint != startEndpoints[i] {
+			t.Errorf("Expected %s but got %s", startEndpoints[i], endpoint)
+		}
+	}
+}
+
+func TestTargetFilterSource(t *testing.T) {
+	t.Parallel()
+
+	t.Run("Interface", TestTargetFilterSourceImplementsSource)
+	t.Run("Endpoints", TestTargetFilterSourceEndpoints)
+}
+
+// TestTargetFilterSourceImplementsSource tests that targetFilterSource is a valid Source.
+func TestTargetFilterSourceImplementsSource(t *testing.T) {
+	var _ Source = &targetFilterSource{}
+}
+
+func TestTargetFilterSourceEndpoints(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		title     string
+		filters   endpoint.TargetFilterInterface
+		endpoints []*endpoint.Endpoint
+		expected  []*endpoint.Endpoint
+	}{
+		{
+			title:   "filter exclusion all",
+			filters: NewMockTargetNetFilter([]string{}),
+			endpoints: []*endpoint.Endpoint{
+				endpoint.NewEndpoint("foo", "A", "1.2.3.4"),
+				endpoint.NewEndpoint("foo", "A", "1.2.3.5"),
+				endpoint.NewEndpoint("foo", "A", "1.2.3.6"),
+				endpoint.NewEndpoint("foo", "A", "1.3.4.5"),
+				endpoint.NewEndpoint("foo", "A", "1.4.4.5")},
+			expected: []*endpoint.Endpoint{},
+		},
+		{
+			title:   "filter exclude internal net",
+			filters: NewMockTargetNetFilter([]string{"8.8.8.8"}),
+			endpoints: []*endpoint.Endpoint{
+				endpoint.NewEndpoint("foo", "A", "10.0.0.1"),
+				endpoint.NewEndpoint("foo", "A", "8.8.8.8")},
+			expected: []*endpoint.Endpoint{endpoint.NewEndpoint("foo", "A", "8.8.8.8")},
+		},
+		{
+			title:   "filter only internal",
+			filters: NewMockTargetNetFilter([]string{"10.0.0.1"}),
+			endpoints: []*endpoint.Endpoint{
+				endpoint.NewEndpoint("foo", "A", "10.0.0.1"),
+				endpoint.NewEndpoint("foo", "A", "8.8.8.8")},
+			expected: []*endpoint.Endpoint{endpoint.NewEndpoint("foo", "A", "10.0.0.1")},
+		},
+	}
+	for _, tt := range tests {
+		tt := tt
+		t.Run(tt.title, func(t *testing.T) {
+			t.Parallel()
+
+			echo := NewEchoSource(tt.endpoints)
+			src := NewTargetFilterSource(echo, tt.filters)
+
+			endpoints, err := src.Endpoints(context.Background())
+			require.NoError(t, err, "failed to get Endpoints")
+			validateEndpoints(t, endpoints, tt.expected)
+		})
+	}
+}