refactor(config): upgrade deps and remove stdout printing

- validator v9 → v10, go-defaults → creasty/defaults
- Remove fmt.Println on missing config file

Author: ravisuhag

config/config.go

@@ -9,8 +9,8 @@ import (
 	"reflect"
 	"strings"
 
-	"github.com/go-playground/validator"
-	"github.com/mcuadros/go-defaults"
+	"github.com/creasty/defaults"
+	"github.com/go-playground/validator/v10"
 	"github.com/spf13/pflag"
 	"github.com/spf13/viper"
 	"gopkg.in/yaml.v3"
@@ -96,7 +96,7 @@ func (l *Loader) Load(config interface{}) error {
 	}
 
 	// Apply default values before reading configuration
-	defaults.SetDefaults(config)
+	defaults.Set(config)
 
 	// Bind flags dynamically using reflection on `cmdx` tags if a flag set is provided
 	if l.flags != nil {
@@ -116,11 +116,11 @@ func (l *Loader) Load(config interface{}) error {
 		}
 	}
 
-	// Attempt to read the configuration file
+	// Attempt to read the configuration file (missing file is not an error).
 	if err := l.v.ReadInConfig(); err != nil {
 		var configFileNotFoundError viper.ConfigFileNotFoundError
-		if errors.As(err, &configFileNotFoundError) {
-			fmt.Println("Warning: Config file not found. Falling back to defaults and environment variables.")
+		if !errors.As(err, &configFileNotFoundError) && !os.IsNotExist(err) {
+			return fmt.Errorf("failed to read config file: %w", err)
 		}
 	}
 
@@ -139,7 +139,7 @@ func (l *Loader) Load(config interface{}) error {
 
 // Init initializes the configuration file with default values.
 func (l *Loader) Init(config interface{}) error {
-	defaults.SetDefaults(config)
+	defaults.Set(config)
 
 	path := l.v.ConfigFileUsed()
 	if fileExists(path) {

config/config_test.go

@@ -5,7 +5,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/mcuadros/go-defaults"
+	"github.com/creasty/defaults"
 	"github.com/raystack/salt/config"
 	"github.com/spf13/pflag"
 )
@@ -145,7 +145,7 @@ log_level: "info"
 	loader := config.NewLoader(config.WithFile(configFilePath))
 
 	// Apply defaults
-	defaults.SetDefaults(cfg)
+	defaults.Set(cfg)
 	cfg.Server.Port = 3000 // Default value
 	cfg.Server.Host = "default-host.com"
 	cfg.LogLevel = "debug"

config/example_test.go

@@ -0,0 +1,30 @@
+package config_test
+
+import (
+	"fmt"
+	"log"
+
+	"github.com/raystack/salt/config"
+)
+
+func ExampleNewLoader() {
+	type Config struct {
+		Server struct {
+			Port int    `mapstructure:"port" default:"8080"`
+			Host string `mapstructure:"host" default:"localhost"`
+		} `mapstructure:"server"`
+		LogLevel string `mapstructure:"log_level" default:"info"`
+	}
+
+	var cfg Config
+	loader := config.NewLoader(
+		config.WithFile("./config.yaml"),
+		config.WithEnvPrefix("MYAPP"),
+	)
+
+	if err := loader.Load(&cfg); err != nil {
+		log.Fatal(err)
+	}
+
+	fmt.Printf("server: %s:%d, log: %s\n", cfg.Server.Host, cfg.Server.Port, cfg.LogLevel)
+}