feat: support GLAMOUR_STYLE for custom pager styles

main.go

@@ -134,6 +134,20 @@ func sourceFromArg(arg string) (*source, error) {
 	return &source{r, u}, err
 }
 
+// validateStyle checks if the style is a default style, if not, checks that
+// the custom style exists.
+func validateStyle(style string) error {
+	if style != "auto" && glamour.DefaultStyles[style] == nil {
+		style = utils.ExpandPath(style)
+		if _, err := os.Stat(style); os.IsNotExist(err) {
+			return fmt.Errorf("Specified style does not exist: %s", style)
+		} else if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func validateOptions(cmd *cobra.Command) error {
 	// grab config values from Viper
 	width = viper.GetUint("width")
@@ -143,13 +157,8 @@ func validateOptions(cmd *cobra.Command) error {
 
 	// validate the glamour style
 	style = viper.GetString("style")
-	if style != "auto" && glamour.DefaultStyles[style] == nil {
-		style = utils.ExpandPath(style)
-		if _, err := os.Stat(style); os.IsNotExist(err) {
-			return fmt.Errorf("Specified style does not exist: %s", style)
-		} else if err != nil {
-			return err
-		}
+	if err := validateStyle(style); err != nil {
+		return err
 	}
 
 	isTerminal := term.IsTerminal(int(os.Stdout.Fd()))
@@ -329,11 +338,15 @@ func runTUI(workingDirectory string, stashedOnly bool) error {
 		defer f.Close() //nolint:errcheck
 	}
 
+	// use style set in env, or auto if unset
+	if err := validateStyle(cfg.GlamourStyle); err != nil {
+		cfg.GlamourStyle = style
+	}
+
 	cfg.WorkingDirectory = workingDirectory
 	cfg.DocumentTypes = ui.NewDocTypeSet()
 	cfg.ShowAllFiles = showAllFiles
 	cfg.GlamourMaxWidth = width
-	cfg.GlamourStyle = style
 	cfg.EnableMouse = mouse
 
 	if stashedOnly {

ui/config.go

@@ -6,7 +6,7 @@ type Config struct {
 	Gopath          string `env:"GOPATH"`
 	HomeDir         string `env:"HOME"`
 	GlamourMaxWidth uint
-	GlamourStyle    string
+	GlamourStyle    string `env:"GLAMOUR_STYLE"`
 	EnableMouse     bool
 
 	// Which directory should we start from?