Add additional header when debug is enabled

docs/examples/customization/custom-errors/custom-default-backend.yaml

@@ -30,6 +30,11 @@ spec:
     spec:
       containers:
       - name: nginx-error-server
-        image: quay.io/kubernetes-ingress-controller/custom-error-pages-amd64:0.2
+        image: quay.io/kubernetes-ingress-controller/custom-error-pages-amd64:0.3
         ports:
         - containerPort: 8080
+        # Setting the environment variable DEBUG we can see the headers sent 
+        # by the ingress controller to the backend in the client response.
+        # env:
+        # - name: DEBUG
+        #   value: "true"

images/custom-error-pages/Makefile

@@ -3,7 +3,7 @@ all: all-container
 BUILDTAGS=
 
 # Use the 0.0 tag for testing, it shouldn't clobber any release builds
-TAG?=0.2
+TAG?=0.3
 REGISTRY?=quay.io/kubernetes-ingress-controller
 GOOS?=linux
 DOCKER?=docker
@@ -26,11 +26,11 @@ ARCH ?= $(shell go env GOARCH)
 GOARCH = ${ARCH}
 DUMB_ARCH = ${ARCH}
 
-BASEIMAGE?=alpine:3.6
+BASEIMAGE?=alpine:3.7
 
 ALL_ARCH = amd64 arm arm64 ppc64le
 
-QEMUVERSION=v2.9.1
+QEMUVERSION=v2.12.0
 
 IMGNAME = custom-error-pages
 IMAGE = $(REGISTRY)/$(IMGNAME)
@@ -74,7 +74,7 @@ ifeq ($(ARCH),amd64)
 else
 	# When cross-building, only the placeholder "CROSS_BUILD_" should be removed
 	# Register /usr/bin/qemu-ARCH-static as the handler for ARM binaries in the kernel
-	$(DOCKER) run --rm --privileged multiarch/qemu-user-static:register --reset
+	# $(DOCKER) run --rm --privileged multiarch/qemu-user-static:register --reset
 	curl -sSL https://github.com/multiarch/qemu-user-static/releases/download/$(QEMUVERSION)/x86_64_qemu-$(QEMUARCH)-static.tar.gz | tar -xz -C $(TEMP_DIR)/rootfs
 	$(SED_I) "s/CROSS_BUILD_//g" $(DOCKERFILE)
 endif
@@ -103,3 +103,8 @@ build: clean
 
 release: all-container all-push
 	echo "done"
+
+.PHONY: register-qemu
+register-qemu:
+	# Register /usr/bin/qemu-ARCH-static as the handler for binaries in multiple platforms
+	$(DOCKER) run --rm --privileged multiarch/qemu-user-static:register --reset

images/custom-error-pages/main.go

@@ -40,6 +40,21 @@ const (
 	// ContentType name of the header that defines the format of the reply
 	ContentType = "Content-Type"
 
+	// OriginalURI name of the header with the original URL from NGINX
+	OriginalURI = "X-Original-URI"
+
+	// Namespace name of the header that contains information about the Ingress namespace
+	Namespace = "X-Namespace"
+
+	// IngressName name of the header that contains the matched Ingress
+	IngressName = "X-Ingress-Name"
+
+	// ServiceName name of the header that contains the matched Service in the Ingress
+	ServiceName = "X-Service-Name"
+
+	// ServicePort name of the header that contains the matched Service port in the Ingress
+	ServicePort = "X-Service-Port"
+
 	// ErrFilesPathVar is the name of the environment variable indicating
 	// the location on disk of files served by the handler.
 	ErrFilesPathVar = "ERROR_FILES_PATH"
@@ -67,6 +82,17 @@ func errorHandler(path string) func(http.ResponseWriter, *http.Request) {
 		start := time.Now()
 		ext := "html"
 
+		if os.Getenv("DEBUG") != "" {
+			w.Header().Set(FormatHeader, r.Header.Get(FormatHeader))
+			w.Header().Set(CodeHeader, r.Header.Get(CodeHeader))
+			w.Header().Set(ContentType, r.Header.Get(ContentType))
+			w.Header().Set(OriginalURI, r.Header.Get(OriginalURI))
+			w.Header().Set(Namespace, r.Header.Get(Namespace))
+			w.Header().Set(IngressName, r.Header.Get(IngressName))
+			w.Header().Set(ServiceName, r.Header.Get(ServiceName))
+			w.Header().Set(ServicePort, r.Header.Get(ServicePort))
+		}
+
 		format := r.Header.Get(FormatHeader)
 		if format == "" {
 			format = "text/html"