Make static mode compatible with provisioner

This commit adds two features for the static mode:
- Support configuring a single Gateway resource to watch.
- Support not reporting the GatewayClass status,
so that it doesn't conflict with the status updates done by
the provisioner.

Needed by nginxinc#634

cmd/gateway/commands.go

@@ -6,6 +6,7 @@ import (
 	"os"
 
 	"github.com/spf13/cobra"
+	"k8s.io/apimachinery/pkg/types"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"sigs.k8s.io/controller-runtime/pkg/log/zap"
 
@@ -36,7 +37,7 @@ var (
 )
 
 // stringValidatingValue is a string flag value with custom validation logic.
-// stringValidatingValue implements the pflag.Value interface.
+// it implements the pflag.Value interface.
 type stringValidatingValue struct {
 	validator func(v string) error
 	value     string
@@ -58,6 +59,34 @@ func (v *stringValidatingValue) Type() string {
 	return "string"
 }
 
+// namespacedNameValue is a string flag value that represents a namespaced name.
+// it implements the pflag.Value interface.
+type namespacedNameValue struct {
+	value types.NamespacedName
+}
+
+func (v *namespacedNameValue) String() string {
+	if (v.value == types.NamespacedName{}) {
+		// if we don't do that, the default value in the help message will be printed as "/"
+		return ""
+	}
+	return v.value.String()
+}
+
+func (v *namespacedNameValue) Set(param string) error {
+	nsname, err := parseNamespacedResourceName(param)
+	if err != nil {
+		return err
+	}
+
+	v.value = nsname
+	return nil
+}
+
+func (v *namespacedNameValue) Type() string {
+	return "string"
+}
+
 func createRootCommand() *cobra.Command {
 	rootCmd := &cobra.Command{
 		Use: "gateway",
@@ -84,7 +113,13 @@ func createRootCommand() *cobra.Command {
 }
 
 func createStaticModeCommand() *cobra.Command {
-	return &cobra.Command{
+	const gatewayFlag = "gateway"
+
+	// flag values
+	gateway := namespacedNameValue{}
+	var updateGCStatus bool
+
+	cmd := &cobra.Command{
 		Use:   "static-mode",
 		Short: "Configure NGINX in the scope of a single Gateway resource",
 		RunE: func(cmd *cobra.Command, args []string) error {
@@ -100,11 +135,18 @@ func createStaticModeCommand() *cobra.Command {
 				return fmt.Errorf("error validating POD_IP environment variable: %w", err)
 			}
 
+			var gwNsName *types.NamespacedName
+			if cmd.Flags().Changed(gatewayFlag) {
+				gwNsName = &gateway.value
+			}
+
 			conf := config.Config{
-				GatewayCtlrName:  gatewayCtlrName.value,
-				Logger:           logger,
-				GatewayClassName: gatewayClassName.value,
-				PodIP:            podIP,
+				GatewayCtlrName:          gatewayCtlrName.value,
+				Logger:                   logger,
+				GatewayClassName:         gatewayClassName.value,
+				PodIP:                    podIP,
+				GatewayNsName:            gwNsName,
+				UpdateGatewayClassStatus: updateGCStatus,
 			}
 
 			if err := manager.Start(conf); err != nil {
@@ -114,6 +156,25 @@ func createStaticModeCommand() *cobra.Command {
 			return nil
 		},
 	}
+
+	cmd.Flags().Var(
+		&gateway,
+		gatewayFlag,
+		"The namespaced name of the Gateway resource to use. "+
+			"Must be of the form: NAMESPACE/NAME. "+
+			"If not specified, the control plane will process all Gateways for the configured GatewayClass. "+
+			"However, among them, it will choose the oldest resource by creation timestamp. If the timestamps are "+
+			"equal, it will choose the resource that appears first in alphabetical order by {namespace}/{name}.",
+	)
+
+	cmd.Flags().BoolVar(
+		&updateGCStatus,
+		"update-gatewayclass-status",
+		true,
+		"Update the status of the GatewayClass resource.",
+	)
+
+	return cmd
 }
 
 func createProvisionerModeCommand() *cobra.Command {

cmd/gateway/commands_test.go

@@ -5,15 +5,40 @@ import (
 	"testing"
 
 	. "github.com/onsi/gomega"
+	"github.com/spf13/cobra"
 )
 
+type flagTestCase struct {
+	name              string
+	expectedErrPrefix string
+	args              []string
+	wantErr           bool
+}
+
+func testFlag(t *testing.T, cmd *cobra.Command, test flagTestCase) {
+	g := NewGomegaWithT(t)
+	// discard any output generated by cobra
+	cmd.SetOut(io.Discard)
+	cmd.SetErr(io.Discard)
+
+	// override RunE to avoid executing the command
+	cmd.RunE = func(cmd *cobra.Command, args []string) error {
+		return nil
+	}
+
+	cmd.SetArgs(test.args)
+	err := cmd.Execute()
+
+	if test.wantErr {
+		g.Expect(err).To(HaveOccurred())
+		g.Expect(err.Error()).To(HavePrefix(test.expectedErrPrefix))
+	} else {
+		g.Expect(err).NotTo(HaveOccurred())
+	}
+}
+
 func TestRootCmdFlagValidation(t *testing.T) {
-	tests := []struct {
-		name              string
-		expectedErrPrefix string
-		args              []string
-		wantErr           bool
-	}{
+	tests := []flagTestCase{
 		{
 			name: "valid flags",
 			args: []string{
@@ -79,22 +104,66 @@ func TestRootCmdFlagValidation(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.name, func(t *testing.T) {
-			g := NewGomegaWithT(t)
-
 			rootCmd := createRootCommand()
-			// discard any output generated by cobra
-			rootCmd.SetOut(io.Discard)
-			rootCmd.SetErr(io.Discard)
+			testFlag(t, rootCmd, test)
+		})
+	}
+}
 
-			rootCmd.SetArgs(test.args)
-			err := rootCmd.Execute()
+func TestStaticModeCmdFlagValidation(t *testing.T) {
+	tests := []flagTestCase{
+		{
+			name: "valid flags",
+			args: []string{
+				"--gateway=nginx-gateway/nginx",
+				"--update-gatewayclass-status=true",
+			},
+			wantErr: false,
+		},
+		{
+			name:    "valid flags, not set",
+			args:    nil,
+			wantErr: false,
+		},
+		{
+			name: "gateway is set to empty string",
+			args: []string{
+				"--gateway=",
+			},
+			wantErr:           true,
+			expectedErrPrefix: `invalid argument "" for "--gateway" flag: must be set`,
+		},
+		{
+			name: "gateway is invalid",
+			args: []string{
+				"--gateway=nginx-gateway", // no namespace
+			},
+			wantErr: true,
+			expectedErrPrefix: `invalid argument "nginx-gateway" for "--gateway" flag: invalid format; ` +
+				"must be NAMESPACE/NAME",
+		},
+		{
+			name: "update-gatewayclass-status is set to empty string",
+			args: []string{
+				"--update-gatewayclass-status=",
+			},
+			wantErr:           true,
+			expectedErrPrefix: `invalid argument "" for "--update-gatewayclass-status" flag: strconv.ParseBool`,
+		},
+		{
+			name: "update-gatewayclass-status is invalid",
+			args: []string{
+				"--update-gatewayclass-status=invalid", // not a boolean
+			},
+			wantErr:           true,
+			expectedErrPrefix: `invalid argument "invalid" for "--update-gatewayclass-status" flag: strconv.ParseBool`,
+		},
+	}
 
-			if test.wantErr {
-				g.Expect(err).To(HaveOccurred())
-				g.Expect(err.Error()).To(HavePrefix(test.expectedErrPrefix))
-			} else {
-				g.Expect(err).ToNot(HaveOccurred())
-			}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			cmd := createStaticModeCommand()
+			testFlag(t, cmd, test)
 		})
 	}
 }

cmd/gateway/validation.go

@@ -7,6 +7,7 @@ import (
 	"regexp"
 	"strings"
 
+	"k8s.io/apimachinery/pkg/types"
 	"k8s.io/apimachinery/pkg/util/validation"
 )
 
@@ -54,6 +55,40 @@ func validateResourceName(value string) error {
 	return nil
 }
 
+func validateNamespaceName(value string) error {
+	// used by Kubernetes to validate resource namespace names
+	messages := validation.IsDNS1123Label(value)
+	if len(messages) > 0 {
+		msg := strings.Join(messages, "; ")
+		return fmt.Errorf("invalid format: %s", msg)
+	}
+
+	return nil
+}
+
+func parseNamespacedResourceName(value string) (types.NamespacedName, error) {
+	if value == "" {
+		return types.NamespacedName{}, errors.New("must be set")
+	}
+
+	parts := strings.Split(value, "/")
+	if len(parts) != 2 {
+		return types.NamespacedName{}, errors.New("invalid format; must be NAMESPACE/NAME")
+	}
+
+	if err := validateNamespaceName(parts[0]); err != nil {
+		return types.NamespacedName{}, fmt.Errorf("invalid namespace name: %w", err)
+	}
+	if err := validateResourceName(parts[1]); err != nil {
+		return types.NamespacedName{}, fmt.Errorf("invalid resource name: %w", err)
+	}
+
+	return types.NamespacedName{
+		Namespace: parts[0],
+		Name:      parts[1],
+	}, nil
+}
+
 func validateIP(ip string) error {
 	if ip == "" {
 		return errors.New("IP address must be set")