Add name field for viper and logger.

logger.go

@@ -38,30 +38,44 @@ type Logger interface {
 	// Loggers commonly provide Fatal and Panic levels above Error level,
 	// but exiting and panicing is out of scope for a logging library.
 	Error(msg string, keyvals ...interface{})
+
+	// SetName sets a name for logger, the logger name will be the prefix of all the log entry.
+	SetName(string)
 }
 
-type jwwLogger struct{}
+type jwwLogger struct {
+	name string
+}
 
-func (jwwLogger) Trace(msg string, keyvals ...interface{}) {
+func (j *jwwLogger) Trace(msg string, keyvals ...interface{}) {
+	msg = fmt.Sprintf("%s | %s", j.name, msg)
 	jww.TRACE.Printf(jwwLogMessage(msg, keyvals...))
 }
 
-func (jwwLogger) Debug(msg string, keyvals ...interface{}) {
+func (j *jwwLogger) Debug(msg string, keyvals ...interface{}) {
+	msg = fmt.Sprintf("%s | %s", j.name, msg)
 	jww.DEBUG.Printf(jwwLogMessage(msg, keyvals...))
 }
 
-func (jwwLogger) Info(msg string, keyvals ...interface{}) {
+func (j *jwwLogger) Info(msg string, keyvals ...interface{}) {
+	msg = fmt.Sprintf("%s | %s", j.name, msg)
 	jww.INFO.Printf(jwwLogMessage(msg, keyvals...))
 }
 
-func (jwwLogger) Warn(msg string, keyvals ...interface{}) {
+func (j *jwwLogger) Warn(msg string, keyvals ...interface{}) {
+	msg = fmt.Sprintf("%s | %s", j.name, msg)
 	jww.WARN.Printf(jwwLogMessage(msg, keyvals...))
 }
 
-func (jwwLogger) Error(msg string, keyvals ...interface{}) {
+func (j *jwwLogger) Error(msg string, keyvals ...interface{}) {
+	msg = fmt.Sprintf("%s | %s", j.name, msg)
 	jww.ERROR.Printf(jwwLogMessage(msg, keyvals...))
 }
 
+func (j *jwwLogger) SetName(name string) {
+	j.name = name
+}
+
 func jwwLogMessage(msg string, keyvals ...interface{}) string {
 	out := msg
 

viper.go

@@ -180,6 +180,10 @@ func DecodeHook(hook mapstructure.DecodeHookFunc) DecoderConfigOption {
 //
 // Note: Vipers are not safe for concurrent Get() and Set() operations.
 type Viper struct {
+
+	// Will use as both the viper name and the logger name, will be printed as the prefix for each log entry.
+	name string
+
 	// Delimiter that separates a list of keys
 	// used to access a nested value in one go
 	keyDelim string
@@ -231,6 +235,7 @@ type Viper struct {
 // New returns an initialized Viper instance.
 func New() *Viper {
 	v := new(Viper)
+	v.name = "default"
 	v.keyDelim = "."
 	v.configName = "config"
 	v.configPermissions = os.FileMode(0o644)
@@ -244,7 +249,7 @@ func New() *Viper {
 	v.env = make(map[string][]string)
 	v.aliases = make(map[string]string)
 	v.typeByDefValue = false
-	v.logger = jwwLogger{}
+	v.logger = &jwwLogger{name: v.name}
 	v.registered = make(map[string]RegisteredConfig)
 
 	v.resetEncoding()
@@ -642,6 +647,14 @@ func (v *Viper) AddConfigPath(in string) {
 	}
 }
 
+// SetName Updates the name of a Viper object.
+func SetName(name string) { v.SetName(name) }
+
+func (v *Viper) SetName(name string) {
+	v.name = name
+	v.logger.SetName(name)
+}
+
 // AddRemoteProvider adds a remote configuration source.
 // Remote Providers are searched in the order they are added.
 // provider is a string value: "etcd", "etcd3", "consul" or "firestore" are currently supported.