Add command registration helpers

This patch adds helper methods to the CLI to register cobra commands.

Signed-off-by: Alano Terblanche <[email protected]>

Author: Benehiko

internal/commands/commands.go

@@ -0,0 +1,46 @@
+package commands
+
+import (
+	"os"
+	"slices"
+	"sync"
+
+	"github.com/docker/cli/cli/command"
+	"github.com/spf13/cobra"
+)
+
+var (
+	commands []func(command.Cli) *cobra.Command
+	l        sync.RWMutex
+)
+
+func RegisterCommand(f func(command.Cli) *cobra.Command) {
+	l.Lock()
+	defer l.Unlock()
+	commands = append(commands, f)
+}
+
+// MaybeHideLegacy checks the `DOCKER_HIDE_LEGACY_COMMANDS` environment variable and if
+// it has been set and is non-empty, the legacy command will be hidden.
+// Legacy commands are `docker ps`, `docker exec`, etc.
+func MaybeHideLegacy(f func(command.Cli) *cobra.Command) func(command.Cli) *cobra.Command {
+	return func(c command.Cli) *cobra.Command {
+		cmd := f(c)
+		// If the environment variable with name "DOCKER_HIDE_LEGACY_COMMANDS" is not empty,
+		// these legacy commands (such as `docker ps`, `docker exec`, etc)
+		// will not be shown in output console.
+		if os.Getenv("DOCKER_HIDE_LEGACY_COMMANDS") == "" {
+			return cmd
+		}
+		cmdCopy := *cmd
+		cmdCopy.Hidden = true
+		cmdCopy.Aliases = []string{}
+		return &cmdCopy
+	}
+}
+
+func Commands() []func(command.Cli) *cobra.Command {
+	l.RLock()
+	defer l.RUnlock()
+	return slices.Clone(commands)
+}