Cleanup json-related code with additions

`detailsFormat` key removed from config
`MarshalIntoFormat` renamed into `marshalIntoFormat` with better
description
`MarshalIntoYaml` introduced as `marshalIntoFormat` wrapper for common
usage

pkg/config/app_config.go

@@ -130,10 +130,6 @@ type GuiConfig struct {
 	// When true, increases vertical space used by focused side panel,
 	// creating an accordion effect
 	ExpandFocusedSidePanel bool `yaml:"expandFocusedSidePanel"`
-
-	// DetailsFormat determines in which format will be printed container stats and configs
-	// By default "yaml", available values "json", "yaml"
-	DetailsFormat string `yaml:"detailsFormat,omitempty"`
 }
 
 // CommandTemplatesConfig determines what commands actually get called when we
@@ -366,7 +362,6 @@ func GetDefaultConfig() UserConfig {
 			SidePanelWidth:         0.3333,
 			ShowBottomLine:         true,
 			ExpandFocusedSidePanel: false,
-			DetailsFormat:          "yaml",
 		},
 		ConfirmOnQuit: false,
 		Logs: LogsConfig{

pkg/gui/containers_panel.go

@@ -199,7 +199,7 @@ func (gui *Gui) containerConfigStr(container *commands.Container) string {
 		output += "none\n"
 	}
 
-	data, err := utils.MarshalIntoFormat(&container.Details, gui.Config.UserConfig.Gui.DetailsFormat)
+	data, err := utils.MarshalIntoYaml(&container.Details)
 	if err != nil {
 		return fmt.Sprintf("Error marshalling container details: %v", err)
 	}

pkg/gui/presentation/container_stats.go

@@ -37,7 +37,7 @@ func RenderStats(userConfig *config.UserConfig, container *commands.Container, v
 	dataReceived := fmt.Sprintf("Traffic received: %s", utils.FormatDecimalBytes(stats.ClientStats.Networks.Eth0.RxBytes))
 	dataSent := fmt.Sprintf("Traffic sent: %s", utils.FormatDecimalBytes(stats.ClientStats.Networks.Eth0.TxBytes))
 
-	originalStats, err := utils.MarshalIntoFormat(stats, userConfig.Gui.DetailsFormat)
+	originalStats, err := utils.MarshalIntoYaml(stats)
 	if err != nil {
 		return "", err
 	}

pkg/utils/utils.go

@@ -385,7 +385,14 @@ func OpensMenuStyle(str string) string {
 	return ColoredString(fmt.Sprintf("%s...", str), color.FgMagenta)
 }
 
-func MarshalIntoFormat(data interface{}, format string) ([]byte, error) {
+// MarshalIntoYaml gets any json-tagged data and marshal it into yaml saving original json structure.
+// Useful for structs from 3rd-party libs without yaml tags.
+func MarshalIntoYaml(data interface{}) ([]byte, error) {
+	return marshalIntoFormat(data, "yaml")
+}
+
+func marshalIntoFormat(data interface{}, format string) ([]byte, error) {
+	// First marshal struct->json to get the resulting structure declared by json tags
 	dataJSON, err := json.MarshalIndent(data, "", "  ")
 	if err != nil {
 		return nil, err
@@ -394,7 +401,7 @@ func MarshalIntoFormat(data interface{}, format string) ([]byte, error) {
 	case "json":
 		return dataJSON, err
 	case "yaml":
-		// Use Unmarshal->Marshal hack to convert vendor-locked objects to YAML with same structure as JSON
+		// Use Unmarshal->Marshal hack to convert json into yaml with the original structure preserved
 		var dataMirror yaml.MapSlice
 		if err := yaml.Unmarshal(dataJSON, &dataMirror); err != nil {
 			return nil, err

pkg/utils/utils_test.go

@@ -270,7 +270,7 @@ func TestMarshalIntoFormat(t *testing.T) {
 	}
 
 	type scenario struct {
-		input       data
+		input       interface{}
 		format      string
 		expected    []byte
 		expectedErr error
@@ -310,7 +310,7 @@ quux:
 	}
 
 	for _, s := range scenarios {
-		output, err := MarshalIntoFormat(s.input, s.format)
+		output, err := marshalIntoFormat(s.input, s.format)
 		assert.EqualValues(t, s.expected, output)
 		if s.expectedErr != nil {
 			assert.EqualError(t, err, s.expectedErr.Error())