Function HandlePluginCommand

pkg/cmd/plugin.go:109–154

HandlePluginCommand receives a pluginHandler and command-line arguments and attempts to find a plugin executable on the PATH that satisfies the given arguments.

(pluginHandler PluginHandler, cmdArgs []string, minArgs int)

// HandlePluginCommand receives a pluginHandler and command-line arguments and attempts to find
// a plugin executable on the PATH that satisfies the given arguments.
func HandlePluginCommand(pluginHandler PluginHandler, cmdArgs []string, minArgs int) error {
	var remainingArgs []string // all "non-flag" arguments
	for _, arg := range cmdArgs {
		if strings.HasPrefix(arg, "-") {
			break
		}
		remainingArgs = append(remainingArgs, strings.Replace(arg, "-", "_", -1))
	}

	if len(remainingArgs) == 0 {
		// the length of cmdArgs is at least 1
		return fmt.Errorf("flags cannot be placed before plugin name: %s", cmdArgs[0])
	}

	foundBinaryPath := ""

	// attempt to find binary, starting at longest possible name with given cmdArgs
	for len(remainingArgs) > 0 {
		path, found := pluginHandler.Lookup(strings.Join(remainingArgs, "-"))
		if !found {
			remainingArgs = remainingArgs[:len(remainingArgs)-1]
			if len(remainingArgs) < minArgs {
				// we shouldn't continue searching with shorter names.
				// this is especially for not searching kubectl-create plugin
				// when kubectl-create-foo plugin is not found.
				break
			}

			continue
		}

		foundBinaryPath = path
		break
	}

	if len(foundBinaryPath) == 0 {
		return nil
	}

	// invoke cmd binary relaying the current environment and args given
	if err := pluginHandler.Execute(foundBinaryPath, cmdArgs[len(remainingArgs):], os.Environ()); err != nil {
		return err
	}

	return nil
}

// IsSubcommandPluginAllowed returns the given command is allowed
// to use plugin as subcommand if the subcommand does not exist as builtin.