[#493] logger: Simplify Logger's parameters

Replace `viper.Viper` parameter with `Prm` structure. Currently only logging
level can be parameterized through string setter.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>

cmd/neofs-ir/main.go

@@ -44,7 +44,14 @@ func main() {
 	cfg, err := newConfig(*configFile)
 	exitErr(err)
 
-	log, err := logger.NewLogger(cfg)
+	var logPrm logger.Prm
+
+	err = logPrm.SetLevelString(
+		cfg.GetString("logger.level"),
+	)
+	exitErr(err)
+
+	log, err := logger.NewLogger(logPrm)
 	exitErr(err)
 
 	log = log.With(

cmd/neofs-node/config.go

@@ -352,7 +352,14 @@ func initCfg(path string) *cfg {
 		viperCfg.GetString(cfgReputationContract))
 	fatalOnErr(err)
 
-	log, err := logger.NewLogger(viperCfg)
+	var logPrm logger.Prm
+
+	err = logPrm.SetLevelString(
+		viperCfg.GetString(cfgLogLevel),
+	)
+	fatalOnErr(err)
+
+	log, err := logger.NewLogger(logPrm)
 	fatalOnErr(err)
 
 	log = log.With(

pkg/util/logger/logger.go

@@ -2,9 +2,7 @@ package logger
 
 import (
 	"errors"
-	"strings"
 
-	"github.com/spf13/viper"
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
 )
@@ -16,36 +14,38 @@ import (
 // go.uber.org/zap.Logger.
 type Logger = zap.Logger
 
+// Prm groups Logger's parameters.
+type Prm struct {
+	level zapcore.Level
+}
+
 // ErrNilLogger is returned by functions that
 // expect a non-nil Logger, but received nil.
 var ErrNilLogger = errors.New("logger is nil")
 
-// NewLogger is a logger's constructor.
+// SetLevelString sets minimum logging level.
-func NewLogger(v *viper.Viper) (*Logger, error) {
+//
+// Returns error of s is not a string representation of zap.Level
+// value (see zapcore.Level docs).
+func (p *Prm) SetLevelString(s string) error {
+	return p.level.UnmarshalText([]byte(s))
+}
+
+// NewLogger constructs a new zap logger instance.
+//
+// Logger is built from production logging configuration with:
+//  * parameterized level;
+//  * console encoding;
+//  * ISO8601 time encoding.
+//
+// Logger records a stack trace for all messages at or above fatal level.
+func NewLogger(prm Prm) (*Logger, error) {
 	c := zap.NewProductionConfig()
-	c.Level = safeLevel(v.GetString("logger.level"))
+	c.Level = zap.NewAtomicLevelAt(prm.level)
 	c.Encoding = "console"
 	c.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
 
 	return c.Build(
-		// record a stack trace for all messages at or above fatal level
 		zap.AddStacktrace(zap.NewAtomicLevelAt(zap.FatalLevel)),
 	)
 }
-
-func safeLevel(lvl string) zap.AtomicLevel {
-	switch strings.ToLower(lvl) {
-	case "debug":
-		return zap.NewAtomicLevelAt(zap.DebugLevel)
-	case "warn":
-		return zap.NewAtomicLevelAt(zap.WarnLevel)
-	case "error":
-		return zap.NewAtomicLevelAt(zap.ErrorLevel)
-	case "fatal":
-		return zap.NewAtomicLevelAt(zap.FatalLevel)
-	case "panic":
-		return zap.NewAtomicLevelAt(zap.PanicLevel)
-	default:
-		return zap.NewAtomicLevelAt(zap.InfoLevel)
-	}
-}