API Lock CLI OSS port (#12925)

* api lock in oss

* add namespace lock/unlock help

command/namespace_api_lock.go

@@ -0,0 +1,87 @@
+package command
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/hashicorp/vault/helper/namespace"
+	"github.com/mitchellh/cli"
+	"github.com/posener/complete"
+)
+
+var (
+	_ cli.Command             = (*NamespaceAPILockCommand)(nil)
+	_ cli.CommandAutocomplete = (*NamespaceAPILockCommand)(nil)
+)
+
+type NamespaceAPILockCommand struct {
+	*BaseCommand
+}
+
+func (c *NamespaceAPILockCommand) Synopsis() string {
+	return "Lock the API for particular namespaces"
+}
+
+func (c *NamespaceAPILockCommand) Help() string {
+	helpText := `
+Usage: vault namespace lock PATH
+
+	Lock the current namespace, and all descendants:
+
+		$ vault namespace lock
+
+	Lock a child namespace, and all of its descendants (e.g. ns1/ns2/):
+
+		$ vault namespace lock ns1/ns2
+
+` + c.Flags().Help()
+
+	return strings.TrimSpace(helpText)
+}
+
+func (c *NamespaceAPILockCommand) Flags() *FlagSets {
+	return c.flagSet(FlagSetHTTP | FlagSetOutputFormat)
+}
+
+func (c *NamespaceAPILockCommand) AutocompleteArgs() complete.Predictor {
+	return c.PredictVaultNamespaces()
+}
+
+func (c *NamespaceAPILockCommand) AutocompleteFlags() complete.Flags {
+	return c.Flags().Completions()
+}
+
+func (c *NamespaceAPILockCommand) Run(args []string) int {
+	f := c.Flags()
+
+	if err := f.Parse(args); err != nil {
+		c.UI.Error(err.Error())
+		return 1
+	}
+
+	args = f.Args()
+	if len(args) > 1 {
+		c.UI.Error(fmt.Sprintf("Too many arguments (expected 0 or 1, got %d)", len(args)))
+		return 1
+	}
+
+	// current namespace is already encoded in the :client:
+	client, err := c.Client()
+	if err != nil {
+		c.UI.Error(err.Error())
+		return 2
+	}
+
+	optionalChildNSPath := ""
+	if len(args) == 1 {
+		optionalChildNSPath = fmt.Sprintf("/%s", namespace.Canonicalize(args[0]))
+	}
+
+	resp, err := client.Logical().Write(fmt.Sprintf("sys/namespaces/api-lock/lock%s", optionalChildNSPath), nil)
+	if err != nil {
+		c.UI.Error(fmt.Sprintf("Error locking namespace: %v", err))
+		return 2
+	}
+
+	return OutputSecret(c.UI, resp)
+}