feat: add methods annotation for Ingress resource

Add a new "konghq.com/methods" annotation for Ingress resources. This
annotation sets the "methods" property of a Kong route.

From #609

internal/ingress/annotations/annotations.go

@@ -42,6 +42,7 @@ const (
 	preserveHostKey      = "/preserve-host"
 	regexPriorityKey     = "/regex-priority"
 	hostHeaderKey        = "/host-header"
+	methodsKey           = "/methods"
 
 	// DefaultIngressClass defines the default class used
 	// by Kong's ingress controller.
@@ -189,3 +190,12 @@ func ExtractRegexPriority(anns map[string]string) string {
 func ExtractHostHeader(anns map[string]string) string {
 	return valueFromAnnotation(hostHeaderKey, anns)
 }
+
+// ExtractMethods extracts the methods annotation value.
+func ExtractMethods(anns map[string]string) []string {
+	val := valueFromAnnotation(methodsKey, anns)
+	if val == "" {
+		return []string{}
+	}
+	return strings.Split(val, ",")
+}

internal/ingress/annotations/annotations_test.go

@@ -672,3 +672,54 @@ func TestExtractHostHeader(t *testing.T) {
 		})
 	}
 }
+
+func TestExtractMethods(t *testing.T) {
+	type args struct {
+		anns map[string]string
+	}
+	tests := []struct {
+		name string
+		args args
+		want []string
+	}{
+		{
+			name: "empty",
+			want: []string{},
+		},
+		{
+			name: "legacy annotation",
+			args: args{
+				anns: map[string]string{
+					"configuration.konghq.com/methods": "POST,GET",
+				},
+			},
+			want: []string{"POST", "GET"},
+		},
+		{
+			name: "new annotation",
+			args: args{
+				anns: map[string]string{
+					"konghq.com/methods": "POST,GET",
+				},
+			},
+			want: []string{"POST", "GET"},
+		},
+		{
+			name: "annotation priority",
+			args: args{
+				anns: map[string]string{
+					"configuration.konghq.com/methods": "GET,POST",
+					"konghq.com/methods":               "POST,PUT",
+				},
+			},
+			want: []string{"POST", "PUT"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := ExtractMethods(tt.args.anns); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("ExtractMethods() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}

internal/ingress/controller/parser/parser.go

@@ -126,6 +126,7 @@ var supportedCreds = sets.NewString(
 )
 
 var validProtocols = regexp.MustCompile(`\Ahttps$|\Ahttp$|\Agrpc$|\Agrpcs|\Atcp|\Atls$`)
+var validMethods = regexp.MustCompile(`\A[A-Z]+$`)
 
 // New returns a new parser backed with store.
 func New(store store.Storer) Parser {
@@ -943,7 +944,22 @@ func overrideRouteByKongIngress(route *Route,
 
 	r := kongIngress.Route
 	if len(r.Methods) != 0 {
-		route.Methods = cloneStringPointerSlice(r.Methods...)
+		invalid := false
+		var methods []*string
+		for _, method := range r.Methods {
+			sanitizedMethod := strings.TrimSpace(strings.ToUpper(*method))
+			if validMethods.MatchString(sanitizedMethod) {
+				methods = append(methods, kong.String(sanitizedMethod))
+			} else {
+				// if any method is invalid (not an uppercase alpha string),
+				// discard everything
+				glog.Errorf("invalid method found while processing '%v': %v", route.Route.Name, *method)
+				invalid = true
+			}
+		}
+		if !invalid {
+			route.Methods = methods
+		}
 	}
 	if len(r.Headers) != 0 {
 		route.Headers = r.Headers
@@ -1078,6 +1094,27 @@ func overrideRouteRegexPriority(route *kong.Route, anns map[string]string) {
 	route.RegexPriority = kong.Int(regexPriority)
 }
 
+func overrideRouteMethods(route *kong.Route, anns map[string]string) {
+	annMethods := annotations.ExtractMethods(anns)
+	if len(annMethods) == 0 {
+		return
+	}
+	var methods []*string
+	for _, method := range annMethods {
+		sanitizedMethod := strings.TrimSpace(strings.ToUpper(method))
+		if validMethods.MatchString(sanitizedMethod) {
+			methods = append(methods, kong.String(sanitizedMethod))
+		} else {
+			// if any method is invalid (not an uppercase alpha string),
+			// discard everything
+			glog.Errorf("invalid method found while processing '%v': %v", route.Name, method)
+			return
+		}
+	}
+
+	route.Methods = methods
+}
+
 // overrideRouteByAnnotation sets Route protocols via annotation
 func overrideRouteByAnnotation(route *Route) {
 	anns := route.Ingress.Annotations
@@ -1089,6 +1126,7 @@ func overrideRouteByAnnotation(route *Route) {
 	overrideRouteHTTPSRedirectCode(&route.Route, anns)
 	overrideRoutePreserveHost(&route.Route, anns)
 	overrideRouteRegexPriority(&route.Route, anns)
+	overrideRouteMethods(&route.Route, anns)
 }
 
 // overrideRoute sets Route fields by KongIngress first, then by annotation

internal/ingress/controller/parser/parser_test.go

@@ -1198,6 +1198,86 @@ func TestKongServiceAnnotations(t *testing.T) {
 			RegexPriority: kong.Int(0),
 		}, state.Services[0].Routes[0].Route)
 	})
+
+	t.Run("methods annotation is correctly processed",
+		func(t *testing.T) {
+			ingresses := []*networking.Ingress{
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:      "bar",
+						Namespace: "default",
+						Annotations: map[string]string{
+							"konghq.com/methods": "POST,GET",
+						},
+					},
+					Spec: networking.IngressSpec{
+						Rules: []networking.IngressRule{
+							{
+								Host: "example.com",
+								IngressRuleValue: networking.IngressRuleValue{
+									HTTP: &networking.HTTPIngressRuleValue{
+										Paths: []networking.HTTPIngressPath{
+											{
+												Path: "/",
+												Backend: networking.IngressBackend{
+													ServiceName: "foo-svc",
+													ServicePort: intstr.FromInt(80),
+												},
+											},
+										},
+									},
+								},
+							},
+						},
+					},
+				},
+			}
+
+			services := []*corev1.Service{
+				{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:      "foo-svc",
+						Namespace: "default",
+					},
+				},
+			}
+			store, err := store.NewFakeStore(store.FakeObjects{
+				Ingresses: ingresses,
+				Services:  services,
+			})
+			assert.Nil(err)
+			parser := New(store)
+			state, err := parser.Build()
+			assert.Nil(err)
+			assert.NotNil(state)
+
+			assert.Equal(1, len(state.Services),
+				"expected one service to be rendered")
+			assert.Equal(kong.Service{
+				Name:           kong.String("default.foo-svc.80"),
+				Host:           kong.String("foo-svc.default.80.svc"),
+				Path:           kong.String("/"),
+				Port:           kong.Int(80),
+				ConnectTimeout: kong.Int(60000),
+				ReadTimeout:    kong.Int(60000),
+				WriteTimeout:   kong.Int(60000),
+				Retries:        kong.Int(5),
+				Protocol:       kong.String("http"),
+			}, state.Services[0].Service)
+
+			assert.Equal(1, len(state.Services[0].Routes),
+				"expected one route to be rendered")
+			assert.Equal(kong.Route{
+				Name:          kong.String("default.bar.00"),
+				StripPath:     kong.Bool(false),
+				RegexPriority: kong.Int(0),
+				Hosts:         kong.StringSlice("example.com"),
+				PreserveHost:  kong.Bool(true),
+				Paths:         kong.StringSlice("/"),
+				Protocols:     kong.StringSlice("http", "https"),
+				Methods:       kong.StringSlice("POST", "GET"),
+			}, state.Services[0].Routes[0].Route)
+		})
 }
 
 func TestDefaultBackend(t *testing.T) {
@@ -2813,6 +2893,41 @@ func TestOverrideRoute(t *testing.T) {
 				},
 			},
 		},
+		{
+			Route{
+				Route: kong.Route{
+					Hosts: kong.StringSlice("foo.com", "bar.com"),
+				},
+			},
+			configurationv1.KongIngress{
+				Route: &kong.Route{
+					Methods: kong.StringSlice("GET   ", "post"),
+				},
+			},
+			Route{
+				Route: kong.Route{
+					Hosts:   kong.StringSlice("foo.com", "bar.com"),
+					Methods: kong.StringSlice("GET", "POST"),
+				},
+			},
+		},
+		{
+			Route{
+				Route: kong.Route{
+					Hosts: kong.StringSlice("foo.com", "bar.com"),
+				},
+			},
+			configurationv1.KongIngress{
+				Route: &kong.Route{
+					Methods: kong.StringSlice("GET", "-1"),
+				},
+			},
+			Route{
+				Route: kong.Route{
+					Hosts: kong.StringSlice("foo.com", "bar.com"),
+				},
+			},
+		},
 		{
 			Route{
 				Route: kong.Route{
@@ -4655,6 +4770,57 @@ func Test_overrideRouteRegexPriority(t *testing.T) {
 	}
 }
 
+func Test_overrideRouteMethods(t *testing.T) {
+	type args struct {
+		route *kong.Route
+		anns  map[string]string
+	}
+	tests := []struct {
+		name string
+		args args
+		want *kong.Route
+	}{
+		{},
+		{
+			name: "basic empty route",
+			args: args{
+				route: &kong.Route{},
+			},
+			want: &kong.Route{},
+		},
+		{
+			name: "basic sanity",
+			args: args{
+				route: &kong.Route{},
+				anns: map[string]string{
+					"konghq.com/methods": "POST,GET",
+				},
+			},
+			want: &kong.Route{
+				Methods: kong.StringSlice("POST", "GET"),
+			},
+		},
+		{
+			name: "non-string",
+			args: args{
+				route: &kong.Route{},
+				anns: map[string]string{
+					"konghq.com/methods": "-10,GET",
+				},
+			},
+			want: &kong.Route{},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			overrideRouteMethods(tt.args.route, tt.args.anns)
+			if !reflect.DeepEqual(tt.args.route, tt.want) {
+				t.Errorf("overrideRouteMethods() got = %v, want %v", tt.args.route, tt.want)
+			}
+		})
+	}
+}
+
 func Test_knativeSelectSplit(t *testing.T) {
 	type args struct {
 		splits []knative.IngressBackendSplit