add --cache flag

Default state dir moves from os.UserConfigDir to os.UserCacheDir

Author: markferry

README.md

@@ -60,15 +60,18 @@ Details about cross-compiling go-librespot are described [here](/CROSS_COMPILE.m
 
 ## Configuration
 
-The default directory for configuration files is `~/.config/go-librespot`. On macOS devices, this is
-`~/Library/Application Support/go-librespot`. You can change this directory with the
-`--config_dir` flag. The configuration directory contains:
+The main configuration files is `~/.config/go-librespot/config.yaml`. On macOS devices, this is
+`~/Library/Application Support/go-librespot/config.yaml`. It does not exist by default.
 
-- `config.yml`: The main configuration (does not exist by default)
-- `state.json`: The player state and credentials
-- `lockfile`: A lockfile to prevent running multiple instances on the same configuration
+You can change this path with the `--config` flag.
+
+Cache files are stored in `~/.cache/go-librespot` (`~/Library/Caches/go-librespot` on macOS).
 
-You may also specify a custom config file with the `--config` flag.
+You can change this directory with the `--cache` flag.
+
+The cache directory contains:
+- `state.json`: The player state and credentials
+- `lockfile`: A lockfile to prevent multiple instances using the same state
 
 The full configuration schema is available [here](/config_schema.json), only the main options are detailed below.
 

cmd/daemon/main.go

@@ -79,7 +79,7 @@ func NewApp(cfg *Config) (app *App, err error) {
 	}
 
 	app.state.SetLogger(app.log)
-	if err := app.state.Read(cfg.ConfigDir); err != nil {
+	if err := app.state.Read(cfg.CacheDir); err != nil {
 		return nil, err
 	}
 
@@ -368,7 +368,7 @@ func (app *App) withAppPlayer(ctx context.Context, appPlayerFunc func(context.Co
 }
 
 type Config struct {
-	ConfigDir string `koanf:"config_dir"`
+	CacheDir string `koanf:"cache"`
 	ConfigPath string `koanf:"config"`
 
 	// We need to keep this object around, otherwise it gets GC'd and the
@@ -425,8 +425,19 @@ type Config struct {
 	} `koanf:"credentials"`
 }
 
+// backwards compatibility for config_dir flag
+func aliasNormalizeFunc(f *flag.FlagSet, name string) flag.NormalizedName {
+	switch name {
+	case "config_dir":
+		name = "cache"
+		break
+	}
+	return flag.NormalizedName(name)
+}
+
 func loadConfig(cfg *Config) error {
 	f := flag.NewFlagSet("config", flag.ContinueOnError)
+	f.SetNormalizeFunc(aliasNormalizeFunc)
 	f.Usage = func() {
 		fmt.Println(f.FlagUsages())
 		os.Exit(0)
@@ -435,26 +446,30 @@ func loadConfig(cfg *Config) error {
 	if err != nil {
 		return err
 	}
-	defaultConfigDir := filepath.Join(userConfigDir, "go-librespot")
-	f.StringVar(&cfg.ConfigDir, "config_dir", defaultConfigDir, "the configuration directory")
-
-	defaultConfigPath := filepath.Join(defaultConfigDir, "config.yaml")
+	defaultConfigPath := filepath.Join(userConfigDir, "go-librespot", "config.yaml")
 	f.StringVar(&cfg.ConfigPath, "config", defaultConfigPath, "the configuration file")
 
+	userCacheDir, err := os.UserCacheDir()
+	if err != nil {
+		return err
+	}
+	defaultCachePath := filepath.Join(userCacheDir, "go-librespot")
+	f.StringVar(&cfg.CacheDir, "cache", defaultCachePath, "the cache directory")
+
 	err = f.Parse(os.Args[1:])
 	if err != nil {
 		return err
 	}
 
 	// Make config directory if needed.
-	err = os.MkdirAll(cfg.ConfigDir, 0o700)
+	err = os.MkdirAll(cfg.CacheDir, 0o700)
 	if err != nil {
 		return fmt.Errorf("failed creating config directory: %w", err)
 	}
 
 	// Lock the config directory (to ensure multiple instances won't clobber
 	// each others state).
-	lockFilePath := filepath.Join(cfg.ConfigDir, "lockfile")
+	lockFilePath := filepath.Join(cfg.CacheDir, "lockfile")
 	cfg.configLock = flock.New(lockFilePath)
 	if locked, err := cfg.configLock.TryLock(); err != nil {
 		return fmt.Errorf("could not lock config directory: %w", err)
@@ -487,7 +502,8 @@ func loadConfig(cfg *Config) error {
 	// load file configuration (if available)
 	var configPath string
 	if _, err := os.Stat(cfg.ConfigPath); os.IsNotExist(err) {
-		configPath = filepath.Join(cfg.ConfigDir, "config.yml")
+		// postel: allow .yml in place of .yaml
+		configPath = strings.TrimSuffix(cfg.ConfigPath, filepath.Ext(cfg.ConfigPath)) + ".yml"
 	} else {
 		configPath = cfg.ConfigPath
 	}