fix(awssd): use namespace-aware parsing for dotted service names

parseHostname splits at the first dot, which breaks when Cloud Map
service names contain dots (e.g. consumer-gen-mcp.elb in namespace
dev.local). The naive split produces namespace=elb.dev.local instead
of namespace=dev.local, causing the record to be silently skipped.

Change parseHostname to accept known namespaces and use longest-suffix
matching, falling back to the original first-dot split when no
namespace matches for backward compatibility.

Fixes #6364
Ref #5714

Signed-off-by: Andrew Moes <andrew.moes@rewardstyle.com>
Made-with: Cursor

Author: am-ltk

provider/awssd/aws_sd.go

@@ -310,7 +310,7 @@ func (p *AWSSDProvider) submitCreates(ctx context.Context, namespaces []*sdtypes
 		}
 
 		for _, ch := range changeList {
-			_, srvName := p.parseHostname(ch.DNSName)
+			_, srvName := p.parseHostname(ch.DNSName, namespaces)
 
 			srv := services[srvName]
 			if srv == nil {
@@ -350,7 +350,7 @@ func (p *AWSSDProvider) submitDeletes(ctx context.Context, namespaces []*sdtypes
 
 		for _, ch := range changeList {
 			hostname := ch.DNSName
-			_, srvName := p.parseHostname(hostname)
+			_, srvName := p.parseHostname(hostname, namespaces)
 
 			srv := services[srvName]
 			if srv == nil {
@@ -605,7 +605,7 @@ func (p *AWSSDProvider) changesByNamespaceID(namespaces []*sdtypes.NamespaceSumm
 	for _, c := range changes {
 		// trim the trailing dot from hostname if any
 		hostname := strings.TrimSuffix(c.DNSName, ".")
-		nsName, _ := p.parseHostname(hostname)
+		nsName, _ := p.parseHostname(hostname, namespaces)
 
 		matchingNamespaces := matchingNamespaces(nsName, namespaces)
 		if len(matchingNamespaces) == 0 {
@@ -640,8 +640,26 @@ func matchingNamespaces(hostname string, namespaces []*sdtypes.NamespaceSummary)
 	return matchingNamespaces
 }
 
-// parseHostname parse hostname to namespace (domain) and service
-func (p *AWSSDProvider) parseHostname(hostname string) (string, string) {
+// parseHostname parses hostname into namespace (domain) and service name.
+// When known namespaces are provided, it uses longest-suffix matching to
+// correctly handle service names that contain dots (e.g. "foo.bar.dev.local"
+// with namespace "dev.local" yields service "foo.bar"). Falls back to the
+// original first-dot split when no namespace suffix matches.
+func (p *AWSSDProvider) parseHostname(hostname string, namespaces []*sdtypes.NamespaceSummary) (string, string) {
+	var bestNS, bestSrv string
+	for _, ns := range namespaces {
+		suffix := "." + aws.ToString(ns.Name)
+		if strings.HasSuffix(hostname, suffix) {
+			candidate := strings.TrimSuffix(hostname, suffix)
+			if bestNS == "" || len(aws.ToString(ns.Name)) > len(bestNS) {
+				bestNS = aws.ToString(ns.Name)
+				bestSrv = candidate
+			}
+		}
+	}
+	if bestNS != "" {
+		return bestNS, bestSrv
+	}
 	parts := strings.Split(hostname, ".")
 	return strings.Join(parts[1:], "."), parts[0]
 }

provider/awssd/aws_sd_test.go

@@ -280,6 +280,56 @@ func TestAWSSDProvider_ApplyChanges_Update(t *testing.T) {
 	assert.Equal(t, "1.2.3.5", api.deregistered[0], "wrong target de-registered")
 }
 
+func TestAWSSDProvider_ApplyChanges_DottedServiceName(t *testing.T) {
+	namespaces := map[string]*sdtypes.Namespace{
+		"dev-local": {
+			Id:   aws.String("dev-local"),
+			Name: aws.String("dev.local"),
+			Type: sdtypes.NamespaceTypeDnsPrivate,
+		},
+	}
+
+	api := &AWSSDClientStub{
+		namespaces: namespaces,
+		services:   make(map[string]map[string]*sdtypes.Service),
+		instances:  make(map[string]map[string]*sdtypes.Instance),
+	}
+
+	createEndpoints := []*endpoint.Endpoint{
+		{DNSName: "consumer-gen-mcp.elb.dev.local", Targets: endpoint.Targets{"1.2.3.4"}, RecordType: endpoint.RecordTypeA, RecordTTL: 60},
+	}
+
+	provider := newTestAWSSDProvider(api, endpoint.NewDomainFilter([]string{"dev.local"}), "", "")
+
+	ctx := t.Context()
+
+	err := provider.ApplyChanges(ctx, &plan.Changes{
+		Create: createEndpoints,
+	})
+	require.NoError(t, err)
+
+	// service must be created with the dotted name "consumer-gen-mcp.elb"
+	assert.Len(t, api.services["dev-local"], 1)
+	existingServices, err := provider.ListServicesByNamespaceID(ctx, namespaces["dev-local"].Id)
+	require.NoError(t, err)
+	assert.NotNil(t, existingServices["consumer-gen-mcp.elb"], "service should be named 'consumer-gen-mcp.elb'")
+
+	// verify the record round-trips through Records()
+	endpoints, err := provider.Records(ctx)
+	require.NoError(t, err)
+	assert.True(t, testutils.SameEndpoints(createEndpoints, endpoints),
+		"expected and actual endpoints don't match, expected=%v, actual=%v", createEndpoints, endpoints)
+
+	// apply deletes
+	err = provider.ApplyChanges(ctx, &plan.Changes{
+		Delete: createEndpoints,
+	})
+	require.NoError(t, err)
+
+	endpoints, _ = provider.Records(ctx)
+	assert.Empty(t, endpoints)
+}
+
 func TestAWSSDProvider_ListNamespaces(t *testing.T) {
 	namespaces := map[string]*sdtypes.Namespace{
 		"private": {
@@ -1042,3 +1092,84 @@ func TestAWSSDProvider_awsTags(t *testing.T) {
 		require.ElementsMatch(t, test.Expectation, awsTags(test.Input))
 	}
 }
+
+func TestAWSSDProvider_parseHostname(t *testing.T) {
+	tests := []struct {
+		name       string
+		hostname   string
+		namespaces []*sdtypes.NamespaceSummary
+		wantNS     string
+		wantSrv    string
+	}{
+		{
+			name:     "simple service name",
+			hostname: "foo.dev.local",
+			namespaces: []*sdtypes.NamespaceSummary{
+				{Name: aws.String("dev.local")},
+			},
+			wantNS:  "dev.local",
+			wantSrv: "foo",
+		},
+		{
+			name:     "dotted service name",
+			hostname: "foo.bar.dev.local",
+			namespaces: []*sdtypes.NamespaceSummary{
+				{Name: aws.String("dev.local")},
+			},
+			wantNS:  "dev.local",
+			wantSrv: "foo.bar",
+		},
+		{
+			name:     "SRV-style hostname",
+			hostname: "_tcp.backend.mynet.internal",
+			namespaces: []*sdtypes.NamespaceSummary{
+				{Name: aws.String("mynet.internal")},
+			},
+			wantNS:  "mynet.internal",
+			wantSrv: "_tcp.backend",
+		},
+		{
+			name:     "longest namespace match wins",
+			hostname: "foo.a.b.c",
+			namespaces: []*sdtypes.NamespaceSummary{
+				{Name: aws.String("b.c")},
+				{Name: aws.String("a.b.c")},
+			},
+			wantNS:  "a.b.c",
+			wantSrv: "foo",
+		},
+		{
+			name:     "no matching namespace falls back to first-dot split",
+			hostname: "foo.unknown.tld",
+			namespaces: []*sdtypes.NamespaceSummary{
+				{Name: aws.String("dev.local")},
+			},
+			wantNS:  "unknown.tld",
+			wantSrv: "foo",
+		},
+		{
+			name:       "empty namespaces falls back to first-dot split",
+			hostname:   "foo.bar.baz",
+			namespaces: []*sdtypes.NamespaceSummary{},
+			wantNS:     "bar.baz",
+			wantSrv:    "foo",
+		},
+		{
+			name:       "nil namespaces falls back to first-dot split",
+			hostname:   "foo.bar.baz",
+			namespaces: nil,
+			wantNS:     "bar.baz",
+			wantSrv:    "foo",
+		},
+	}
+
+	provider := &AWSSDProvider{}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			gotNS, gotSrv := provider.parseHostname(tc.hostname, tc.namespaces)
+			assert.Equal(t, tc.wantNS, gotNS)
+			assert.Equal(t, tc.wantSrv, gotSrv)
+		})
+	}
+}