Adds CustomHTTPErrors ingress annotation and test

Adds per-server/location error-catch functionality to nginx template

Adds documentation

Reduces template duplication with helper function for CUSTOM_ERRORS data

Updates documentation

Adds e2e test for customerrors

Removes AllCustomHTTPErrors, replaces with template function with deduplication and adds e2e test of deduplication

Fixes copy-paste error in test, adds additional test cases

Reverts noop change in controller.go (unused now)

test/e2e/annotations/customhttperrors.go

@@ -0,0 +1,119 @@
+/*
+Copyright 2018 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 annotations
+
+import (
+	"fmt"
+	"strings"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	"k8s.io/ingress-nginx/test/e2e/framework"
+)
+
+var _ = framework.IngressNginxDescribe("Annotations - custom-http-errors", func() {
+	f := framework.NewDefaultFramework("custom-http-errors")
+
+	BeforeEach(func() {
+		f.NewEchoDeploymentWithReplicas(2)
+	})
+
+	AfterEach(func() {
+	})
+
+	It("should set proxy_intercept_errors", func() {
+		host := "customerrors.foo.com"
+
+		errorCodes := []string{"404", "500"}
+
+		annotations := map[string]string{
+			"nginx.ingress.kubernetes.io/custom-http-errors": strings.Join(errorCodes, ","),
+		}
+
+		ing := framework.NewSingleIngress(host, "/", host, f.IngressController.Namespace, "http-svc", 80, &annotations)
+		f.EnsureIngress(ing)
+
+		f.WaitForNginxServer(host,
+			func(server string) bool {
+				return Expect(server).Should(ContainSubstring("proxy_intercept_errors on;"))
+			})
+	})
+
+	It("should create error routes", func() {
+		host := "customerrors.foo.com"
+		errorCodes := []string{"404", "500"}
+
+		annotations := map[string]string{
+			"nginx.ingress.kubernetes.io/custom-http-errors": strings.Join(errorCodes, ","),
+		}
+
+		ing := framework.NewSingleIngress(host, "/test", host, f.IngressController.Namespace, "http-svc", 80, &annotations)
+		f.EnsureIngress(ing)
+
+		for _, code := range errorCodes {
+			f.WaitForNginxServer(host,
+				func(server string) bool {
+					return Expect(server).Should(ContainSubstring(fmt.Sprintf("@custom_%s", code)))
+				})
+		}
+	})
+
+	It("should set up error_page routing", func() {
+		host := "customerrors.foo.com"
+		errorCodes := []string{"404", "500"}
+
+		annotations := map[string]string{
+			"nginx.ingress.kubernetes.io/custom-http-errors": strings.Join(errorCodes, ","),
+		}
+
+		ing := framework.NewSingleIngress(host, "/test", host, f.IngressController.Namespace, "http-svc", 80, &annotations)
+		f.EnsureIngress(ing)
+
+		for _, code := range errorCodes {
+			f.WaitForNginxServer(host,
+				func(server string) bool {
+					return Expect(server).Should(ContainSubstring(fmt.Sprintf("error_page %s = @custom_%s", code, code)))
+				})
+		}
+	})
+
+	It("should create only one of each error route", func() {
+		host := "customerrors.foo.com"
+		errorCodes := [][]string{{"404", "500"}, {"400", "404"}}
+
+		for i, codeSet := range errorCodes {
+			annotations := map[string]string{
+				"nginx.ingress.kubernetes.io/custom-http-errors": strings.Join(codeSet, ","),
+			}
+
+			ing := framework.NewSingleIngress(
+				fmt.Sprintf("%s-%d", host, i), fmt.Sprintf("/test-%d", i),
+				host, f.IngressController.Namespace, "http-svc", 80, &annotations)
+			f.EnsureIngress(ing)
+		}
+
+		for _, codeSet := range errorCodes {
+			for _, code := range codeSet {
+				f.WaitForNginxServer(host,
+					func(server string) bool {
+						count := strings.Count(server, fmt.Sprintf("location @custom_%s", code))
+						return Expect(count).Should(Equal(1))
+					})
+			}
+		}
+	})
+})