Add websocket support

Author: ciarams87

internal/mode/static/nginx/config/maps_template.go

@@ -17,4 +17,11 @@ map $http_host $gw_api_compliant_host {
     '' $host;
     default $http_host;
 }
+
+# Set $connection_header variable to upgrade when the $http_upgrade header is set, otherwise, set it to close. This
+# allows support for websocket connections. See https://nginx.org/en/docs/http/websocket.html.
+map $http_upgrade $connection_upgrade {
+    default upgrade;
+    '' close;
+}
 `

internal/mode/static/nginx/config/maps_test.go

@@ -85,6 +85,7 @@ func TestExecuteMaps(t *testing.T) {
 		"~.* ${http_my_second_add_header},;":                                  1,
 		"map ${http_my_set_header} $my_set_header_header_var {":               0,
 		"map $http_host $gw_api_compliant_host {":                             1,
+		"map $http_upgrade $connection_upgrade {":                             1,
 	}
 
 	maps := string(executeMaps(conf))

internal/mode/static/nginx/config/servers_template.go

@@ -51,6 +51,8 @@ server {
         proxy_set_header {{ $h.Name }} "{{ $h.Value }}";
             {{- end }}
         proxy_set_header Host $gw_api_compliant_host;
+        proxy_set_header Upgrade $http_upgrade;
+        proxy_set_header Connection $connection_upgrade;
         proxy_pass {{ $l.ProxyPass }}$request_uri;
         {{- end }}
     }

internal/mode/static/nginx/config/validation/common.go

@@ -52,8 +52,8 @@ func validateEscapedStringNoVarExpansion(value string, examples []string) error
 }
 
 const (
-	invalidHostHeaderErrMsg string = "redefining the Host request header is not supported"
-	maxHeaderLength         int    = 256
+	invalidHeadersErrMsg string = "redefining the Host, Connection, or Upgrade request headers is not supported"
+	maxHeaderLength      int    = 256
 )
 
 func validateHeaderName(name string) error {
@@ -63,8 +63,8 @@ func validateHeaderName(name string) error {
 	if msg := k8svalidation.IsHTTPHeaderName(name); msg != nil {
 		return errors.New(msg[0])
 	}
-	if strings.ToLower(name) == "host" {
-		return errors.New(invalidHostHeaderErrMsg)
+	if strings.ToLower(name) == "host" || strings.ToLower(name) == "connection" || strings.ToLower(name) == "upgrade" {
+		return errors.New(invalidHeadersErrMsg)
 	}
 	return nil
 }

internal/mode/static/nginx/config/validation/common_test.go

@@ -64,6 +64,8 @@ func TestValidateValidHeaderName(t *testing.T) {
 		`$test`,
 		"Host",
 		"host",
+		"connection",
+		"upgrade",
 		"my-header[]",
 		"my-header&",
 		strings.Repeat("very-long-header", 16)+"1",

internal/mode/static/nginx/config/validation/http_filters_test.go

@@ -74,7 +74,7 @@ func TestValidateRequestHeaderName(t *testing.T) {
 		t,
 		validator.ValidateRequestHeaderName,
 		"Content-Encoding",
-		"Connection",
+		"MyBespokeHeader",
 	)
 
 	testInvalidValuesForSimpleValidator(t, validator.ValidateRequestHeaderName, "$Content-Encoding")

internal/mode/static/state/dataplane/configuration_test.go

@@ -1609,8 +1609,8 @@ func TestCreateFilters(t *testing.T) {
 		RequestHeaderModifier: &v1beta1.HTTPHeaderFilter{
 			Set: []v1beta1.HTTPHeader{
 				{
-					Name:  "Connection",
-					Value: "close",
+					Name:  "MyBespokeHeader",
+					Value: "my-value",
 				},
 			},
 		},

internal/mode/static/state/graph/httproute_test.go

@@ -1836,7 +1836,7 @@ func TestValidateFilterRequestHeaderModifier(t *testing.T) {
 				Type: v1beta1.HTTPRouteFilterRequestHeaderModifier,
 				RequestHeaderModifier: &v1beta1.HTTPHeaderFilter{
 					Set: []v1beta1.HTTPHeader{
-						{Name: "Connection", Value: "close"},
+						{Name: "MyBespokeHeader", Value: "my-value"},
 					},
 					Add: []v1beta1.HTTPHeader{
 						{Name: "Accept-Encoding", Value: "gzip"},