[Cherry-pick] fix: Do not add request-termination on TLSRoute / TCPRoute (#7700) (#7720)

* fix: Do not add request-termination on TLSRoute / TCPRoute

* fix: add import of strings and check nil

* fix unit tests and golden test cases

* add changelog

---------

Co-authored-by: Victor Durand <contact@victordurand.fr>

Author: randmonkey

CHANGELOG.md

@@ -116,6 +116,10 @@ Adding a new version? You'll need three changes:
 
 ### Fixed
 
+- Add `request-termination` plugin to return `500` if there are no available
+  `backendRef` only when the service is translated from `HTTPRoute` or
+  `GRPCRoute`.
+  [#7720](https://github.com/Kong/kubernetes-ingress-controller/pull/7720)
 - Do not skip the gateway listeners without `Programmed` condition set to `True`
   when the gateway class does not contain `konghq.com/gateway-unmanaged`
   annotation in extracting certificates from listeners. This fixes the issue

internal/dataplane/testdata/golden/tcproute-example/default_golden.yaml

@@ -4,11 +4,6 @@ services:
   host: tcproute.tcp-namespace.echo-plaintext.0
   id: e2302e1e-0a75-5174-82f3-c0bc379a108a
   name: tcproute.tcp-namespace.echo-plaintext.0
-  plugins:
-  - config:
-      message: no existing backendRef provided
-      status_code: 500
-    name: request-termination
   protocol: tcp
   read_timeout: 60000
   retries: 5

internal/dataplane/testdata/golden/tcproute-example/expression-routes-on_golden.yaml

@@ -4,11 +4,6 @@ services:
   host: tcproute.tcp-namespace.echo-plaintext.0
   id: e2302e1e-0a75-5174-82f3-c0bc379a108a
   name: tcproute.tcp-namespace.echo-plaintext.0
-  plugins:
-  - config:
-      message: no existing backendRef provided
-      status_code: 500
-    name: request-termination
   protocol: tcp
   read_timeout: 60000
   retries: 5

internal/dataplane/testdata/golden/tlsroute-example/default_golden.yaml

@@ -4,11 +4,6 @@ services:
   host: tlsroute.tls-namespace.echo-tls.0
   id: 2a2aad7c-6331-5bcf-bd7c-d9516639f65d
   name: tlsroute.tls-namespace.echo-tls.0
-  plugins:
-  - config:
-      message: no existing backendRef provided
-      status_code: 500
-    name: request-termination
   protocol: tcp
   read_timeout: 60000
   retries: 5

internal/dataplane/testdata/golden/tlsroute-example/expression-routes-on_golden.yaml

@@ -4,11 +4,6 @@ services:
   host: tlsroute.tls-namespace.echo-tls.0
   id: 2a2aad7c-6331-5bcf-bd7c-d9516639f65d
   name: tlsroute.tls-namespace.echo-tls.0
-  plugins:
-  - config:
-      message: no existing backendRef provided
-      status_code: 500
-    name: request-termination
   protocol: tcp
   read_timeout: 60000
   retries: 5

internal/dataplane/testdata/golden/udproute-example/default_golden.yaml

@@ -4,11 +4,6 @@ services:
   host: udproute.udp-example.tftp.0
   id: 439fc57a-baff-51a3-9e1f-4e6af6b9dcae
   name: udproute.udp-example.tftp.0
-  plugins:
-  - config:
-      message: no existing backendRef provided
-      status_code: 500
-    name: request-termination
   protocol: udp
   read_timeout: 60000
   retries: 5

internal/dataplane/testdata/golden/udproute-example/expression-routes-on_golden.yaml

@@ -4,11 +4,6 @@ services:
   host: udproute.udp-example.tftp.0
   id: 439fc57a-baff-51a3-9e1f-4e6af6b9dcae
   name: udproute.udp-example.tftp.0
-  plugins:
-  - config:
-      message: no existing backendRef provided
-      status_code: 500
-    name: request-termination
   protocol: udp
   read_timeout: 60000
   retries: 5

internal/dataplane/translator/translate_utils.go

@@ -2,6 +2,7 @@ package translator
 
 import (
 	"fmt"
+	"strings"
 
 	"github.com/go-logr/logr"
 	"github.com/kong/go-kong/kong"
@@ -79,13 +80,16 @@ func generateKongServiceFromBackendRefWithName(
 		if service.Plugins == nil {
 			service.Plugins = make([]kong.Plugin, 0)
 		}
-		service.Plugins = append(service.Plugins, kong.Plugin{
-			Name: kong.String("request-termination"),
-			Config: kong.Configuration{
-				"status_code": 500,
-				"message":     "no existing backendRef provided",
-			},
-		})
+		if service.Protocol != nil &&
+			(strings.Contains(*service.Protocol, "http") || strings.Contains(*service.Protocol, "grpc")) {
+			service.Plugins = append(service.Plugins, kong.Plugin{
+				Name: kong.String("request-termination"),
+				Config: kong.Configuration{
+					"status_code": 500,
+					"message":     "no existing backendRef provided",
+				},
+			})
+		}
 	}
 
 	return service, nil

internal/dataplane/translator/translate_utils_test.go

@@ -290,14 +290,8 @@ func TestGenerateKongServiceFromBackendRef(t *testing.T) {
 				},
 				Namespace: "behbudiy",
 				Backends:  []kongstate.ServiceBackend{},
-				Plugins: []kong.Plugin{
-					{
-						Name: kong.String("request-termination"),
-						Config: kong.Configuration{
-							"status_code": 500,
-							"message":     "no existing backendRef provided",
-						},
-					},
+				Plugins:   []kong.Plugin{
+					// No request-termination plugin is added for services with protocol not containing `http` or `grpc`.
 				},
 				Parent: &gatewayapi.TCPRoute{
 					ObjectMeta: metav1.ObjectMeta{