Add override for proxy_intercept_errors when using Custom HTTP Errors (#9497)

* added proxy-intercept-errors config option

* fixed error when comparing locations

* fixed missing location config from annotation
added e2e test

* reversed logic for proxy-intercept-errors to disable-proxy-intercept-errors

* reversed logic to disable-proxy-intercept-errors

* reversed logic

* default has to be false

* put comment in same line as return

* run gofmt

* fixing wrong Boilerplate header

* updated code to new IngressAnnotation interface

* fixes to satisfy PR comments

* synced with upstream; fixed typo

* gofumpt disableproxyintercepterrors.go

* gofumpt

internal/ingress/annotations/disableproxyintercepterrors/main.go

@@ -0,0 +1,76 @@
+/*
+Copyright 2023 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 disableproxyintercepterrors
+
+import (
+	networking "k8s.io/api/networking/v1"
+
+	"k8s.io/ingress-nginx/internal/ingress/annotations/parser"
+	"k8s.io/ingress-nginx/internal/ingress/errors"
+	"k8s.io/ingress-nginx/internal/ingress/resolver"
+)
+
+const (
+	disableProxyInterceptErrorsAnnotation = "disable-proxy-intercept-errors"
+)
+
+var disableProxyInterceptErrorsAnnotations = parser.Annotation{
+	Group: "backend",
+	Annotations: parser.AnnotationFields{
+		disableProxyInterceptErrorsAnnotation: {
+			Validator: parser.ValidateBool,
+			Scope:     parser.AnnotationScopeLocation,
+			Risk:      parser.AnnotationRiskLow,
+			Documentation: `This annotation allows to disable NGINX proxy-intercept-errors when custom-http-errors are set.
+			If a default backend annotation is specified on the ingress, the errors will be routed to that annotation's default backend service (instead of the global default backend).
+			Different ingresses can specify different sets of errors codes and there are UseCases where NGINX shall not intercept all errors returned from upstream.`,
+		},
+	},
+}
+
+type disableProxyInterceptErrors struct {
+	r                resolver.Resolver
+	annotationConfig parser.Annotation
+}
+
+func (pie disableProxyInterceptErrors) GetDocumentation() parser.AnnotationFields {
+	return pie.annotationConfig.Annotations
+}
+
+func (pie disableProxyInterceptErrors) Validate(anns map[string]string) error {
+	maxrisk := parser.StringRiskToRisk(pie.r.GetSecurityConfiguration().AnnotationsRiskLevel)
+	return parser.CheckAnnotationRisk(anns, maxrisk, disableProxyInterceptErrorsAnnotations.Annotations)
+}
+
+// NewParser creates a new disableProxyInterceptErrors annotation parser
+func NewParser(r resolver.Resolver) parser.IngressAnnotation {
+	return disableProxyInterceptErrors{
+		r:                r,
+		annotationConfig: disableProxyInterceptErrorsAnnotations,
+	}
+}
+
+func (pie disableProxyInterceptErrors) Parse(ing *networking.Ingress) (interface{}, error) {
+	val, err := parser.GetBoolAnnotation(disableProxyInterceptErrorsAnnotation, ing, pie.annotationConfig.Annotations)
+
+	// A missing annotation is not a problem, just use the default
+	if err == errors.ErrMissingAnnotations {
+		return false, nil // default is false
+	}
+
+	return val, nil
+}