isle/go/daemon/network/config.go

package network

import (
	"errors"
	"fmt"
	"io/fs"
	"isle/daemon/daecommon"
	"isle/jsonutil"
	"isle/toolkit"
	"path/filepath"
)

func configPath(networkStateDir toolkit.Dir) string {
	return filepath.Join(networkStateDir.Path, "config.json")
}

// loadConfig loads the stored NetworkConfig and returns it, or returns the
// default NetworkConfig if none is stored.
func loadConfig(networkStateDir toolkit.Dir) (daecommon.NetworkConfig, error) {
	path := configPath(networkStateDir)

	var config daecommon.NetworkConfig
	if err := jsonutil.LoadFile(&config, path); errors.Is(err, fs.ErrNotExist) {
		return daecommon.NewNetworkConfig(nil), nil
	} else if err != nil {
		return daecommon.NetworkConfig{}, fmt.Errorf(
			"loading %q: %w", path, err,
		)
	}

	return config, nil
}

// loadStoreConfig writes the given NetworkConfig to the networkStateDir if the
// config is non-nil. If the config is nil then a config is read from
// networkStateDir, returning the zero value if no config was previously
// stored.
func loadStoreConfig(
	networkStateDir toolkit.Dir, config *daecommon.NetworkConfig,
) (
	daecommon.NetworkConfig, error,
) {
	if config == nil {
		return loadConfig(networkStateDir)
	}

	path := configPath(networkStateDir)
	if err := jsonutil.WriteFile(*config, path, 0600); err != nil {
		return daecommon.NetworkConfig{}, fmt.Errorf(
			"writing to %q: %w", path, err,
		)
	}

	return *config, nil
}