server-sent events support through new annotation

controllers/nginx/configuration.md

@@ -50,6 +50,7 @@ The following annotations are supported:
 |[ingress.kubernetes.io/auth-tls-verify-depth](#certificate-authentication)|number|
 |[ingress.kubernetes.io/configuration-snippet](#configuration-snippet)|string|
 |[ingress.kubernetes.io/enable-cors](#enable-cors)|true or false|
+|[ingress.kubernetes.io/eventsource](#eventsource)|true or false|
 |[ingress.kubernetes.io/force-ssl-redirect](#server-side-https-enforcement-through-redirect)|true or false|
 |[ingress.kubernetes.io/limit-connections](#rate-limiting)|number|
 |[ingress.kubernetes.io/limit-rps](#rate-limiting)|number|
@@ -228,6 +229,10 @@ If the `service-upstream` annotation is specified the following things should be
 * Sticky Sessions will not work as only round-robin load balancing is supported. 
 * The `proxy_next_upstream` directive will not have any effect meaning on error the request will not be dispatched to another upstream.
 
+### Eventsource
+
+The annotation `ingress.kubernetes.io/eventsource` sets headers to be compatible with Server Sent Events. 
+
 ### Server-side HTTPS enforcement through redirect
 
 By default the controller redirects (301) to `HTTPS` if TLS is enabled for that ingress. If you want to disable that behaviour globally, you can use `ssl-redirect: "false"` in the NGINX config map.

controllers/nginx/rootfs/etc/nginx/template/nginx.tmpl

@@ -420,9 +420,16 @@ http {
             proxy_set_header ssl-client-cert        $ssl_client_cert;
             {{ end }}
 
+            {{ if $location.Eventsource }}
+            # Allow server sent events
+            proxy_set_header                        Connection        '';
+            proxy_cache                             off;
+            chunked_transfer_encoding               off;
+            {{ else }}
             # Allow websocket connections
             proxy_set_header                        Upgrade           $http_upgrade;
             proxy_set_header                        Connection        $connection_upgrade;
+            {{ end }}
 
             proxy_set_header X-Real-IP              $the_real_ip;
             proxy_set_header X-Forwarded-For        $the_real_ip;

core/pkg/ingress/annotations/eventsource/main.go

@@ -0,0 +1,38 @@
+/*
+Copyright 2017 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 eventsource
+
+import (
+	extensions "k8s.io/api/extensions/v1beta1"
+
+	"k8s.io/ingress/core/pkg/ingress/annotations/parser"
+)
+
+const (
+	annotation = "ingress.kubernetes.io/eventsource"
+)
+
+type eventsource struct {
+}
+
+func NewParser() parser.IngressAnnotation {
+	return eventsource{}
+}
+
+func (a eventsource) Parse(ing *extensions.Ingress) (interface{}, error) {
+	return parser.GetBoolAnnotation(annotation, ing)
+}

core/pkg/ingress/annotations/eventsource/main_test.go

@@ -0,0 +1,63 @@
+/*
+Copyright 2017 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 eventsource
+
+import (
+	"testing"
+
+	api "k8s.io/api/core/v1"
+	extensions "k8s.io/api/extensions/v1beta1"
+	meta_v1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+)
+
+const (
+	notEventsourceAnnotation = "ingress.kubernetes.io/not-eventsource"
+)
+
+func TestParse(t *testing.T) {
+	ap := NewParser()
+	if ap == nil {
+		t.Fatalf("expected a parser.IngressAnnotation but returned nil")
+	}
+
+	testCases := []struct {
+		annotations map[string]string
+		expected    bool
+	}{
+		{map[string]string{annotation: "true"}, true},
+		{map[string]string{annotation: "false"}, false},
+		{map[string]string{notEventsourceAnnotation: "true"}, false},
+		{map[string]string{}, false},
+		{nil, false},
+	}
+
+	ing := &extensions.Ingress{
+		ObjectMeta: meta_v1.ObjectMeta{
+			Name:      "foo",
+			Namespace: api.NamespaceDefault,
+		},
+		Spec: extensions.IngressSpec{},
+	}
+
+	for _, testCase := range testCases {
+		ing.SetAnnotations(testCase.annotations)
+		result, _ := ap.Parse(ing)
+		if result != testCase.expected {
+			t.Errorf("expected %t but returned %t, annotations: %s", testCase.expected, result, testCase.annotations)
+		}
+	}
+}

core/pkg/ingress/controller/annotations.go

@@ -23,6 +23,7 @@ import (
 	"k8s.io/ingress/core/pkg/ingress/annotations/authreq"
 	"k8s.io/ingress/core/pkg/ingress/annotations/authtls"
 	"k8s.io/ingress/core/pkg/ingress/annotations/cors"
+	"k8s.io/ingress/core/pkg/ingress/annotations/eventsource"
 	"k8s.io/ingress/core/pkg/ingress/annotations/healthcheck"
 	"k8s.io/ingress/core/pkg/ingress/annotations/ipwhitelist"
 	"k8s.io/ingress/core/pkg/ingress/annotations/parser"
@@ -58,6 +59,7 @@ func newAnnotationExtractor(cfg extractorConfig) annotationExtractor {
 			"ExternalAuth":         authreq.NewParser(),
 			"CertificateAuth":      authtls.NewParser(cfg),
 			"EnableCORS":           cors.NewParser(),
+			"Eventsource":          eventsource.NewParser(),
 			"HealthCheck":          healthcheck.NewParser(cfg),
 			"Whitelist":            ipwhitelist.NewParser(cfg),
 			"UsePortInRedirects":   portinredirect.NewParser(cfg),

core/pkg/ingress/controller/util_test.go

@@ -97,6 +97,7 @@ func TestMergeLocationAnnotations(t *testing.T) {
 		"BasicDigestAuth":    auth.BasicDigest{},
 		DeniedKeyName:        &fakeError{},
 		"EnableCORS":         true,
+		"Eventsource":        true,
 		"ExternalAuth":       authreq.External{},
 		"RateLimit":          ratelimit.RateLimit{},
 		"Redirect":           rewrite.Redirect{},

core/pkg/ingress/types.go

@@ -265,6 +265,9 @@ type Location struct {
 	// EnableCORS indicates if path must support CORS
 	// +optional
 	EnableCORS bool `json:"enableCors,omitempty"`
+	// Eventsource indicates the path is a server sent events endpoint
+	// +optional
+	Eventsource bool `json:"eventsource,omitempty"`
 	// ExternalAuth indicates the access to this location requires
 	// authentication using an external provider
 	// +optional

core/pkg/ingress/types_equals.go

@@ -353,6 +353,9 @@ func (l1 *Location) Equal(l2 *Location) bool {
 	if l1.EnableCORS != l2.EnableCORS {
 		return false
 	}
+	if l1.Eventsource != l2.Eventsource {
+		return false
+	}
 	if !(&l1.ExternalAuth).Equal(&l2.ExternalAuth) {
 		return false
 	}