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

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() {