Add GRPC Buffer Size to the Configmap (#11155)

* feat: add grpc buffer size in the nginx template

* feat: add grpc buffer size in the configmap struct

* feat: add test for GRCP buffer size configuration in the configmap

* chore: add documentation for the grcp buffer size configuration

* fix: fix the copyright year of the test

* fix: fix import order

* fix: fix ignore for the linter - reason was missing

* chore: seems like we don't need to ignore the error handling

docs/user-guide/nginx-configuration/configmap.md

@@ -26,7 +26,7 @@ data:
 The following table shows a configuration option's name, type, and the default value:
 
 |name| type         | default                                                                                                                                                                                                                                                                                                                                                      |notes|
-|:---|:---|:------|:----|
+|:---|:-------------|:-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|:----|
 |[add-headers](#add-headers)| string       | ""                                                                                                                                                                                                                                                                                                                                                           ||
 |[allow-backend-server-header](#allow-backend-server-header)| bool         | "false"                                                                                                                                                                                                                                                                                                                                                      ||
 |[allow-cross-namespace-resources](#allow-cross-namespace-resources)| bool         | "true"                                                                                                                                                                                                                                                                                                                                                       ||
@@ -234,6 +234,7 @@ The following table shows a configuration option's name, type, and the default v
 |[ssl-reject-handshake](#ssl-reject-handshake)| bool         | "false"                                                                                                                                                                                                                                                                                                                                                      ||
 |[debug-connections](#debug-connections)| []string     | "127.0.0.1,1.1.1.1/24"                                                                                                                                                                                                                                                                                                                                       ||
 |[strict-validate-path-type](#strict-validate-path-type)| bool         | "false" (v1.7.x)                                                                                                                                                                                                                                                                                                                                             ||
+|[grpc-buffer-size-kb](#grpc-buffer-size-kb)| int          | 0                                                                                                                                                                                                                                                                                                                                                            ||
 
 ## add-headers
 
@@ -1432,3 +1433,10 @@ This means that Ingress objects that rely on paths containing regex characters s
 
 The cluster admin should establish validation rules using mechanisms like [Open Policy Agent](https://www.openpolicyagent.org/) to 
 validate that only authorized users can use `ImplementationSpecific` pathType and that only the authorized characters can be used.
+
+## grpc-buffer-size-kb
+
+Sets the configuration for the GRPC Buffer Size parameter. If not set it will use the default from NGINX.
+
+_References:_
+[https://nginx.org/en/docs/http/ngx_http_grpc_module.html#grpc_buffer_size](https://nginx.org/en/docs/http/ngx_http_grpc_module.html#grpc_buffer_size)

internal/ingress/controller/config/config.go

@@ -20,9 +20,8 @@ import (
 	"strconv"
 	"time"
 
-	"k8s.io/klog/v2"
-
 	apiv1 "k8s.io/api/core/v1"
+	"k8s.io/klog/v2"
 
 	"k8s.io/ingress-nginx/internal/ingress/defaults"
 	"k8s.io/ingress-nginx/pkg/apis/ingress"
@@ -752,6 +751,11 @@ type Configuration struct {
 	// alphanumeric chars, "-", "_", "/".In case of additional characters,
 	// like used on Rewrite configurations the user should use pathType as ImplementationSpecific
 	StrictValidatePathType bool `json:"strict-validate-path-type"`
+
+	// GRPCBufferSizeKb Sets the size of the buffer used for reading the response received
+	// from the gRPC server. The response is passed to the client synchronously,
+	// as soon as it is received.
+	GRPCBufferSizeKb int `json:"grpc-buffer-size-kb"`
 }
 
 // NewDefault returns the default nginx configuration
@@ -917,6 +921,7 @@ func NewDefault() Configuration {
 		GlobalRateLimitStatucCode:              429,
 		DebugConnections:                       []string{},
 		StrictValidatePathType:                 false, // TODO: This will be true in future releases
+		GRPCBufferSizeKb:                       0,
 	}
 
 	if klog.V(5).Enabled() {

rootfs/etc/nginx/template/nginx.tmpl

@@ -331,6 +331,10 @@ http {
     client_body_buffer_size         {{ $cfg.ClientBodyBufferSize }};
     client_body_timeout             {{ $cfg.ClientBodyTimeout }}s;
 
+    {{ if gt $cfg.GRPCBufferSizeKb 0 }}
+    grpc_buffer_size {{ $cfg.GRPCBufferSizeKb }}k;
+    {{ end }}
+
     {{ if and (ne $cfg.HTTP2MaxHeaderSize "") (ne $cfg.HTTP2MaxFieldSize "") }}
     http2_max_field_size            {{ $cfg.HTTP2MaxFieldSize }};
     http2_max_header_size           {{ $cfg.HTTP2MaxHeaderSize }};

test/e2e/settings/grpc.go

@@ -0,0 +1,110 @@
+/*
+Copyright 2024 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 settings
+
+import (
+	"context"
+	"crypto/tls"
+	"fmt"
+	"strings"
+
+	pb "github.com/moul/pb/grpcbin/go-grpc"
+	"github.com/onsi/ginkgo/v2"
+	"github.com/stretchr/testify/assert"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/intstr"
+
+	"k8s.io/ingress-nginx/test/e2e/framework"
+)
+
+const echoHost = "echo"
+
+var _ = framework.DescribeSetting("GRPC", func() {
+	f := framework.NewDefaultFramework("grpc-buffersize", framework.WithHTTPBunEnabled())
+
+	ginkgo.It("should set the correct GRPC Buffer Size", func() {
+		f.SetNginxConfigMapData(map[string]string{
+			"grpc-buffer-size-kb": "8",
+		})
+
+		f.WaitForNginxConfiguration(
+			func(cfg string) bool {
+				return strings.Contains(cfg, "grpc_buffer_size 8k")
+			})
+
+		f.NewGRPCBinDeployment()
+
+		host := echoHost
+
+		svc := &corev1.Service{
+			ObjectMeta: metav1.ObjectMeta{
+				Name:      "grpcbin-test",
+				Namespace: f.Namespace,
+			},
+			Spec: corev1.ServiceSpec{
+				ExternalName: fmt.Sprintf("grpcbin.%v.svc.cluster.local", f.Namespace),
+				Type:         corev1.ServiceTypeExternalName,
+				Ports: []corev1.ServicePort{
+					{
+						Name:       host,
+						Port:       9000,
+						TargetPort: intstr.FromInt(9000),
+						Protocol:   "TCP",
+					},
+				},
+			},
+		}
+		f.EnsureService(svc)
+
+		annotations := map[string]string{
+			"nginx.ingress.kubernetes.io/backend-protocol": "GRPC",
+		}
+
+		ing := framework.NewSingleIngressWithTLS(host, "/", host, []string{host}, f.Namespace, "grpcbin-test", 9000, annotations)
+
+		f.EnsureIngress(ing)
+
+		f.WaitForNginxServer(host,
+			func(server string) bool {
+				return strings.Contains(server, "grpc_pass grpc://upstream_balancer;")
+			})
+
+		conn, err := grpc.Dial(f.GetNginxIP()+":443",
+			grpc.WithTransportCredentials(
+				credentials.NewTLS(&tls.Config{
+					ServerName:         echoHost,
+					InsecureSkipVerify: true, //nolint:gosec // Ignore certificate validation in testing
+				}),
+			),
+		)
+		assert.Nil(ginkgo.GinkgoT(), err, "error creating a connection")
+		defer conn.Close()
+
+		client := pb.NewGRPCBinClient(conn)
+		ctx := context.Background()
+
+		res, err := client.HeadersUnary(ctx, &pb.EmptyMessage{})
+		assert.Nil(ginkgo.GinkgoT(), err)
+
+		metadata := res.GetMetadata()
+		assert.Equal(ginkgo.GinkgoT(), metadata["content-type"].Values[0], "application/grpc")
+		assert.Equal(ginkgo.GinkgoT(), metadata[":authority"].Values[0], host)
+	})
+})