config: use config notifier to call UpdateDefaults()

There are calls to config.UpdateDefaults in pkg/crc/api/ to reload the
configuration settings every time a config is set/unset. This ensures the
default cpus/memory values are correct when the preset changes.

Then there is code in pkg/crc/config.Set()/Unset() to reset the cpus/memory
values when the preset changes if they are out of spec.

This commit groups in UpdateDefaults all the work that is needed when
the preset changes. It moves the Set/Unset UpdateDefaults calls from
pkg/crc/api to pkg/crc/config

This should fix crc-org#3652

pkg/crc/api/handlers.go

@@ -191,7 +191,6 @@ func (h *Handler) SetConfig(c *context) error {
 	if len(multiError.Errors) != 0 {
 		return multiError
 	}
-	crcConfig.UpdateDefaults(h.Config)
 	return c.JSON(http.StatusOK, client.SetOrUnsetConfigResult{
 		Properties: successProps,
 	})
@@ -220,7 +219,6 @@ func (h *Handler) UnsetConfig(c *context) error {
 	if len(multiError.Errors) != 0 {
 		return multiError
 	}
-	crcConfig.UpdateDefaults(h.Config)
 	return c.JSON(http.StatusOK, client.SetOrUnsetConfigResult{
 		Properties: successProps,
 	})

pkg/crc/config/settings.go

@@ -136,15 +136,7 @@ func RegisterSettings(cfg *Config) {
 }
 
 func presetChanged(cfg *Config, _ string, _ interface{}) {
-	// The `memory` and `cpus` values are preset-dependent.
-	// When they are lower than the preset requirements, this code
-	// automatically resets them to their default value.
-	if err := revalidateSettingsValue(cfg, Memory); err != nil {
-		logging.Debugf("error validating Memory config value: %v", err)
-	}
-	if err := revalidateSettingsValue(cfg, CPUs); err != nil {
-		logging.Debugf("error validating CPUs config value: %v", err)
-	}
+	UpdateDefaults(cfg)
 }
 
 func defaultCPUs(cfg Storage) int {
@@ -189,8 +181,20 @@ func revalidateSettingsValue(cfg *Config, key string) error {
 	return nil
 }
 
-func UpdateDefaults(cfg *Config) {
+func UpdateDefaults(cfg *Config) error {
 	RegisterSettings(cfg)
+
+	// The `memory` and `cpus` values are preset-dependent.
+	// When they are lower than the preset requirements, this code
+	// automatically resets them to their default value.
+	if err := revalidateSettingsValue(cfg, Memory); err != nil {
+		return err
+	}
+	if err := revalidateSettingsValue(cfg, CPUs); err != nil {
+		return err
+	}
+
+	return nil
 }
 
 func BundleHelpMsg(cfg *Config) string {