List available auth methods in command output (#400)

Makefile

@@ -45,7 +45,7 @@ release:
 	$(call build,tcld,windows,amd64,.exe)
 
 tools:
-	@go install github.com/golangci/golangci-lint/cmd/golangci-lint@v1.51.2
+	@go install github.com/golangci/golangci-lint/cmd/golangci-lint@v1.60.1
 	@go install github.com/golang/mock/mockgen@latest
 
 lint:

app/namespace.go

@@ -48,6 +48,15 @@ const (
 	AuthMethodAPIKeyOrMTLS = "api_key_or_mtls"
 )
 
+var (
+	AuthMethods = []string{
+		AuthMethodRestricted,
+		AuthMethodMTLS,
+		AuthMethodAPIKey,
+		AuthMethodAPIKeyOrMTLS,
+	}
+)
+
 var (
 	CaCertificateFlag = &cli.StringFlag{
 		Name:    CaCertificateFlagName,
@@ -927,7 +936,8 @@ func NewNamespaceCommand(getNamespaceClientFn GetNamespaceClientFn) (CommandOut,
 						ResourceVersionFlag,
 						&cli.StringFlag{
 							Name:     authMethodFlagName,
-							Usage:    "The authentication method used for the namespace (e.g. 'mtls', 'api_key')",
+							Aliases:  []string{"am"},
+							Usage:    fmt.Sprintf("The authentication method used for the namespace (i.e. %s)", formatAuthMethods()),
 							Required: true,
 						},
 					},
@@ -1997,6 +2007,14 @@ func compareCodecSpec(existing, replacement *namespace.CodecServerPropertySpec)
 	return diff.Diff(string(existingBytes), string(replacementBytes)), nil
 }
 
+func formatAuthMethods() string {
+	var methods []string
+	for _, m := range AuthMethods {
+		methods = append(methods, fmt.Sprintf("'%s'", m))
+	}
+	return strings.Join(methods, ", ")
+}
+
 func disruptiveChange(old namespace.AuthMethod, new namespace.AuthMethod) bool {
 	return old != namespace.AUTH_METHOD_RESTRICTED && new != namespace.AUTH_METHOD_API_KEY_OR_MTLS
 }