Add external authentication using auth_request

ingress/controllers/nginx/controller.go

@@ -42,6 +42,7 @@ import (
 
 	"k8s.io/contrib/ingress/controllers/nginx/nginx"
 	"k8s.io/contrib/ingress/controllers/nginx/nginx/auth"
+	"k8s.io/contrib/ingress/controllers/nginx/nginx/authreq"
 	"k8s.io/contrib/ingress/controllers/nginx/nginx/config"
 	"k8s.io/contrib/ingress/controllers/nginx/nginx/cors"
 	"k8s.io/contrib/ingress/controllers/nginx/nginx/healthcheck"
@@ -723,6 +724,12 @@ func (lbc *loadBalancerController) getUpstreamServers(ngxCfg config.Configuratio
 				glog.V(3).Infof("error reading CORS annotation in Ingress %v/%v: %v", ing.GetNamespace(), ing.GetName(), err)
 			}
 
+			ra, err := authreq.ParseAnnotations(ing)
+			glog.V(3).Infof("nginx auth request %v", ra)
+			if err != nil {
+				glog.V(3).Infof("error reading auth request annotation in Ingress %v/%v: %v", ing.GetNamespace(), ing.GetName(), err)
+			}
+
 			host := rule.Host
 			if host == "" {
 				host = defServerName

ingress/controllers/nginx/nginx/authreq/main.go

@@ -0,0 +1,82 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+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 authreq
+
+import (
+	"errors"
+	"fmt"
+	"net/url"
+	"strings"
+
+	"k8s.io/kubernetes/pkg/apis/extensions"
+)
+
+const (
+	// external URL that provides the authentication
+	authURL = "ingress.kubernetes.io/auth-url"
+)
+
+var (
+	// ErrMissingAnnotations is returned when the ingress rule
+	// does not contains annotations related with authentication
+	ErrMissingAnnotations = errors.New("missing authentication annotations")
+)
+
+type ingAnnotations map[string]string
+
+func (a ingAnnotations) url() (string, error) {
+	val, ok := a[authURL]
+	if !ok {
+		return "", ErrMissingAnnotations
+	}
+
+	return val, nil
+}
+
+// ParseAnnotations parses the annotations contained in the ingress
+// rule used to use an external URL as source for authentication
+func ParseAnnotations(ing *extensions.Ingress) (string, error) {
+	if ing.GetAnnotations() == nil {
+		return "", ErrMissingAnnotations
+	}
+
+	str, err := ingAnnotations(ing.GetAnnotations()).url()
+	if err != nil {
+		return "", err
+	}
+
+	if str == "" {
+		return "", fmt.Errorf("an empty string is not a valid URL")
+	}
+
+	ur, err := url.Parse(str)
+	if err != nil {
+		return "", err
+	}
+	if ur.Scheme == "" {
+		return "", fmt.Errorf("url scheme is empty")
+	}
+	if ur.Host == "" {
+		return "", fmt.Errorf("url host is empty")
+	}
+
+	if strings.Index(ur.Host, "..") != -1 {
+		return "", fmt.Errorf("invalid url host")
+	}
+
+	return str, nil
+}

ingress/controllers/nginx/nginx/authreq/main_test.go

@@ -0,0 +1,99 @@
+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+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 authreq
+
+import (
+	"testing"
+
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/apis/extensions"
+	"k8s.io/kubernetes/pkg/util/intstr"
+)
+
+func buildIngress() *extensions.Ingress {
+	defaultBackend := extensions.IngressBackend{
+		ServiceName: "default-backend",
+		ServicePort: intstr.FromInt(80),
+	}
+
+	return &extensions.Ingress{
+		ObjectMeta: api.ObjectMeta{
+			Name:      "foo",
+			Namespace: api.NamespaceDefault,
+		},
+		Spec: extensions.IngressSpec{
+			Backend: &extensions.IngressBackend{
+				ServiceName: "default-backend",
+				ServicePort: intstr.FromInt(80),
+			},
+			Rules: []extensions.IngressRule{
+				{
+					Host: "foo.bar.com",
+					IngressRuleValue: extensions.IngressRuleValue{
+						HTTP: &extensions.HTTPIngressRuleValue{
+							Paths: []extensions.HTTPIngressPath{
+								{
+									Path:    "/foo",
+									Backend: defaultBackend,
+								},
+							},
+						},
+					},
+				},
+			},
+		},
+	}
+}
+
+func TestAnnotations(t *testing.T) {
+	ing := buildIngress()
+
+	_, err := ingAnnotations(ing.GetAnnotations()).url()
+	if err == nil {
+		t.Error("Expected a validation error")
+	}
+
+	data := map[string]string{}
+	ing.SetAnnotations(data)
+
+	tests := []struct {
+		title  string
+		url    string
+		expErr bool
+	}{
+		{"empty", "", true},
+		{"no scheme", "bar", true},
+		{"invalid host", "http://", true},
+		{"invalid host (multiple dots)", "http://foo..bar.com", true},
+		{"valid URL", "http://bar.foo.com/external-auth", false},
+	}
+
+	for _, test := range tests {
+		t.Run(test.title, func(t *testing.T) {
+			data[authURL] = test.url
+			u, err := ParseAnnotations(ing)
+
+			if test.expErr && err == nil {
+				t.Errorf("expected error but retuned nil")
+			}
+
+			if !test.expErr && u != test.url {
+				t.Errorf("expected \"%v\" but \"%v\" was returned", test.url, u)
+			}
+		})
+	}
+}