auto backend protocol for HTTP/HTTPS (#6985)

* add auto backend protocol for HTTP/HTTPS

* e2e test for AUTO_HTTP backend protocol

* unit  test for AUTO_HTTP backend protocol

Co-authored-by: Luca Del Monte <luca.delmonte5@gmail.com>

internal/ingress/annotations/backendprotocol/main.go

@@ -31,7 +31,7 @@ import (
 const HTTP = "HTTP"
 
 var (
-	validProtocols = regexp.MustCompile(`^(HTTP|HTTPS|AJP|GRPC|GRPCS|FCGI)$`)
+	validProtocols = regexp.MustCompile(`^(AUTO_HTTP|HTTP|HTTPS|AJP|GRPC|GRPCS|FCGI)$`)
 )
 
 type backendProtocol struct {

internal/ingress/controller/template/template.go

@@ -617,6 +617,8 @@ func buildProxyPass(host string, b interface{}, loc interface{}) string {
 	proxyPass := "proxy_pass"
 
 	switch location.BackendProtocol {
+	case "AUTO_HTTP":
+		proto = "$scheme://"
 	case "HTTPS":
 		proto = "https://"
 	case "GRPC":

internal/ingress/controller/template/template_test.go

@@ -59,20 +59,22 @@ func init() {
 var (
 	// TODO: add tests for SSLPassthrough
 	tmplFuncTestcases = map[string]struct {
-		Path             string
+		Path              string
-		Target           string
+		Target            string
-		Location         string
+		Location          string
-		ProxyPass        string
+		ProxyPass         string
-		Sticky           bool
+		AutoHttpProxyPass string
-		XForwardedPrefix string
+		Sticky            bool
-		SecureBackend    bool
+		XForwardedPrefix  string
-		enforceRegex     bool
+		SecureBackend     bool
+		enforceRegex      bool
 	}{
 		"when secure backend enabled": {
 			"/",
 			"/",
 			"/",
 			"proxy_pass https://upstream_balancer;",
+			"proxy_pass https://upstream_balancer;",
 			false,
 			"",
 			true,
@@ -83,6 +85,7 @@ var (
 			"/",
 			"/",
 			"proxy_pass https://upstream_balancer;",
+			"proxy_pass https://upstream_balancer;",
 			false,
 			"",
 			true,
@@ -93,6 +96,7 @@ var (
 			"/",
 			"/",
 			"proxy_pass https://upstream_balancer;",
+			"proxy_pass https://upstream_balancer;",
 			true,
 			"",
 			true,
@@ -103,6 +107,7 @@ var (
 			"/",
 			"/",
 			"proxy_pass http://upstream_balancer;",
+			"proxy_pass $scheme://upstream_balancer;",
 			false,
 			"",
 			false,
@@ -113,6 +118,7 @@ var (
 			"/",
 			"/",
 			"proxy_pass http://upstream_balancer;",
+			"proxy_pass $scheme://upstream_balancer;",
 			false,
 			"",
 			false,
@@ -125,6 +131,9 @@ var (
 			`
 rewrite "(?i)/" /jenkins break;
 proxy_pass http://upstream_balancer;`,
+			`
+rewrite "(?i)/" /jenkins break;
+proxy_pass $scheme://upstream_balancer;`,
 			false,
 			"",
 			false,
@@ -137,6 +146,9 @@ proxy_pass http://upstream_balancer;`,
 			`
 rewrite "(?i)/" /something break;
 proxy_pass http://upstream_balancer;`,
+			`
+rewrite "(?i)/" /something break;
+proxy_pass $scheme://upstream_balancer;`,
 			true,
 			"",
 			false,
@@ -149,6 +161,9 @@ proxy_pass http://upstream_balancer;`,
 			`
 rewrite "(?i)/" /something break;
 proxy_pass http://upstream_balancer;`,
+			`
+rewrite "(?i)/" /something break;
+proxy_pass $scheme://upstream_balancer;`,
 			true,
 			"",
 			false,
@@ -162,6 +177,10 @@ proxy_pass http://upstream_balancer;`,
 rewrite "(?i)/there" /something break;
 proxy_set_header X-Forwarded-Prefix "/there";
 proxy_pass http://upstream_balancer;`,
+			`
+rewrite "(?i)/there" /something break;
+proxy_set_header X-Forwarded-Prefix "/there";
+proxy_pass $scheme://upstream_balancer;`,
 			true,
 			"/there",
 			false,
@@ -172,6 +191,7 @@ proxy_pass http://upstream_balancer;`,
 			"/something",
 			`~* "^/something"`,
 			"proxy_pass http://upstream_balancer;",
+			"proxy_pass $scheme://upstream_balancer;",
 			false,
 			"",
 			false,
@@ -344,6 +364,48 @@ func TestBuildProxyPass(t *testing.T) {
 	}
 }
 
+func TestBuildProxyPassAutoHttp(t *testing.T) {
+	defaultBackend := "upstream-name"
+	defaultHost := "example.com"
+
+	for k, tc := range tmplFuncTestcases {
+		loc := &ingress.Location{
+			Path:             tc.Path,
+			Rewrite:          rewrite.Config{Target: tc.Target},
+			Backend:          defaultBackend,
+			XForwardedPrefix: tc.XForwardedPrefix,
+		}
+
+		if tc.SecureBackend {
+			loc.BackendProtocol = "HTTPS"
+		} else {
+			loc.BackendProtocol = "AUTO_HTTP"
+		}
+
+		backend := &ingress.Backend{
+			Name: defaultBackend,
+		}
+
+		if tc.Sticky {
+			backend.SessionAffinity = ingress.SessionAffinityConfig{
+				AffinityType: "cookie",
+				CookieSessionAffinity: ingress.CookieSessionAffinity{
+					Locations: map[string][]string{
+						defaultHost: {tc.Path},
+					},
+				},
+			}
+		}
+
+		backends := []*ingress.Backend{backend}
+
+		pp := buildProxyPass(defaultHost, backends, loc)
+		if !strings.EqualFold(tc.AutoHttpProxyPass, pp) {
+			t.Errorf("%s: expected \n'%v'\nbut returned \n'%v'", k, tc.ProxyPass, pp)
+		}
+	}
+}
+
 func TestBuildAuthLocation(t *testing.T) {
 	invalidType := &ingress.Ingress{}
 	expected := ""
@@ -899,13 +961,14 @@ func TestEscapeLiteralDollar(t *testing.T) {
 
 func TestOpentracingPropagateContext(t *testing.T) {
 	tests := map[*ingress.Location]string{
-		{BackendProtocol: "HTTP"}:  "opentracing_propagate_context;",
+		{BackendProtocol: "HTTP"}:      "opentracing_propagate_context;",
-		{BackendProtocol: "HTTPS"}: "opentracing_propagate_context;",
+		{BackendProtocol: "HTTPS"}:     "opentracing_propagate_context;",
-		{BackendProtocol: "GRPC"}:  "opentracing_grpc_propagate_context;",
+		{BackendProtocol: "AUTO_HTTP"}: "opentracing_propagate_context;",
-		{BackendProtocol: "GRPCS"}: "opentracing_grpc_propagate_context;",
+		{BackendProtocol: "GRPC"}:      "opentracing_grpc_propagate_context;",
-		{BackendProtocol: "AJP"}:   "opentracing_propagate_context;",
+		{BackendProtocol: "GRPCS"}:     "opentracing_grpc_propagate_context;",
-		{BackendProtocol: "FCGI"}:  "opentracing_propagate_context;",
+		{BackendProtocol: "AJP"}:       "opentracing_propagate_context;",
-		nil:                        "",
+		{BackendProtocol: "FCGI"}:      "opentracing_propagate_context;",
+		nil:                            "",
 	}
 
 	for loc, expectedDirective := range tests {

test/e2e/annotations/backendprotocol.go

@@ -46,6 +46,21 @@ var _ = framework.DescribeAnnotation("backend-protocol", func() {
 			})
 	})
 
+	ginkgo.It("should set backend protocol to $scheme:// and use proxy_pass", func() {
+		host := "backendprotocol.foo.com"
+		annotations := map[string]string{
+			"nginx.ingress.kubernetes.io/backend-protocol": "AUTO_HTTP",
+		}
+
+		ing := framework.NewSingleIngress(host, "/", host, f.Namespace, framework.EchoService, 80, annotations)
+		f.EnsureIngress(ing)
+
+		f.WaitForNginxServer(host,
+			func(server string) bool {
+				return strings.Contains(server, "proxy_pass $scheme://upstream_balancer;")
+			})
+	})
+
 	ginkgo.It("should set backend protocol to grpc:// and use grpc_pass", func() {
 		host := "backendprotocol.foo.com"
 		annotations := map[string]string{