config: Make fs.ConfigFileGet return an exists flag

fs/config.go

@@ -15,7 +15,7 @@ var (
 	//
 	// This is a function pointer to decouple the config
 	// implementation from the fs
-	ConfigFileGet = func(section, key string, defaultVal ...string) string { return "" }
+	ConfigFileGet = func(section, key string) (string, bool) { return "", false }
 
 	// CountError counts an error.  If any errors have been
 	// counted then it will exit with a non zero error code.

fs/config/config.go

@@ -82,7 +82,7 @@ var (
 
 func init() {
 	// Set the function pointer up in fs
-	fs.ConfigFileGet = FileGet
+	fs.ConfigFileGet = FileGetFlag
 }
 
 func getConfigData() *goconfig.ConfigFile {
@@ -1108,6 +1108,19 @@ func Authorize(args []string) {
 	fs.Config(name)
 }
 
+// FileGetFlag gets the config key under section returning the
+// the value and true if found and or ("", false) otherwise
+//
+// It looks up defaults in the environment if they are present
+func FileGetFlag(section, key string) (string, bool) {
+	newValue, err := getConfigData().GetValue(section, key)
+	if err == nil {
+		return newValue, true
+	}
+	envKey := fs.ConfigToEnv(section, key)
+	return os.LookupEnv(envKey)
+}
+
 // FileGet gets the config key under section returning the
 // default or empty string if not set.
 //

fs/fs.go

@@ -790,9 +790,10 @@ func MustFind(name string) *RegInfo {
 func ParseRemote(path string) (fsInfo *RegInfo, configName, fsPath string, err error) {
 	configName, fsPath = fspath.Parse(path)
 	var fsName string
+	var ok bool
 	if configName != "" {
-		fsName = ConfigFileGet(configName, "type")
-		if fsName == "" {
+		fsName, ok = ConfigFileGet(configName, "type")
+		if !ok {
 			return nil, "", "", ErrorNotFoundInConfigFile
 		}
 	} else {