[#89] Add support zapjournald logger configuration

Signed-off-by: Roman Loginov <r.loginov@yadro.com>

cmd/http-gw/settings.go

@@ -19,15 +19,22 @@ import (
 	grpctracing "git.frostfs.info/TrueCloudLab/frostfs-observability/tracing/grpc"
 	"git.frostfs.info/TrueCloudLab/frostfs-sdk-go/pool"
 	treepool "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/pool/tree"
+	"git.frostfs.info/TrueCloudLab/zapjournald"
 	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
 	"github.com/spf13/pflag"
 	"github.com/spf13/viper"
+	"github.com/ssgreg/journald"
 	"github.com/valyala/fasthttp"
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
 	"google.golang.org/grpc"
 )
 
+const (
+	destinationStdout   = "stdout"
+	destinationJournald = "journald"
+)
+
 const (
 	defaultRebalanceTimer = 60 * time.Second
 	defaultRequestTimeout = 15 * time.Second
@@ -74,7 +81,8 @@ const (
 	cfgPoolErrorThreshold = "pool_error_threshold"
 
 	// Logger.
-	cfgLoggerLevel = "logger.level"
+	cfgLoggerLevel       = "logger.level"
+	cfgLoggerDestination = "logger.destination"
 
 	// Wallet.
 	cfgWalletPassphrase = "wallet.passphrase"
@@ -165,6 +173,7 @@ func settings() *viper.Viper {
 
 	// logger:
 	v.SetDefault(cfgLoggerLevel, "debug")
+	v.SetDefault(cfgLoggerDestination, "stdout")
 
 	// pool:
 	v.SetDefault(cfgPoolErrorThreshold, defaultPoolErrorThreshold)
@@ -349,7 +358,25 @@ func mergeConfig(v *viper.Viper, fileName string) error {
 	return v.MergeConfig(cfgFile)
 }
 
-// newLogger constructs a zap.Logger instance for current application.
+func pickLogger(v *viper.Viper) (*zap.Logger, zap.AtomicLevel) {
+	lvl, err := getLogLevel(v)
+	if err != nil {
+		panic(err)
+	}
+
+	dest := v.GetString(cfgLoggerDestination)
+
+	switch dest {
+	case destinationStdout:
+		return newStdoutLogger(lvl)
+	case destinationJournald:
+		return newJournaldLogger(lvl)
+	default:
+		panic(fmt.Sprintf("wrong destination for logger: %s", dest))
+	}
+}
+
+// newStdoutLogger constructs a zap.Logger instance for current application.
 // Panics on failure.
 //
 // Logger is built from zap's production logging configuration with:
@@ -360,12 +387,7 @@ func mergeConfig(v *viper.Viper, fileName string) error {
 // Logger records a stack trace for all messages at or above fatal level.
 //
 // See also zapcore.Level, zap.NewProductionConfig, zap.AddStacktrace.
-func newLogger(v *viper.Viper) (*zap.Logger, zap.AtomicLevel) {
-	lvl, err := getLogLevel(v)
-	if err != nil {
-		panic(err)
-	}
-
+func newStdoutLogger(lvl zapcore.Level) (*zap.Logger, zap.AtomicLevel) {
 	c := zap.NewProductionConfig()
 	c.Level = zap.NewAtomicLevelAt(lvl)
 	c.Encoding = "console"
@@ -381,6 +403,25 @@ func newLogger(v *viper.Viper) (*zap.Logger, zap.AtomicLevel) {
 	return l, c.Level
 }
 
+func newJournaldLogger(lvl zapcore.Level) (*zap.Logger, zap.AtomicLevel) {
+	c := zap.NewProductionConfig()
+	c.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
+	c.Level = zap.NewAtomicLevelAt(lvl)
+
+	encoder := zapcore.NewConsoleEncoder(c.EncoderConfig)
+
+	core := zapjournald.NewCore(zap.NewAtomicLevelAt(lvl), encoder, &journald.Journal{}, zapjournald.SyslogFields)
+	coreWithContext := core.With([]zapcore.Field{
+		zapjournald.SyslogFacility(zapjournald.LogDaemon),
+		zapjournald.SyslogIdentifier(),
+		zapjournald.SyslogPid(),
+	})
+
+	l := zap.New(coreWithContext, zap.AddStacktrace(zap.NewAtomicLevelAt(zap.FatalLevel)))
+
+	return l, c.Level
+}
+
 func getLogLevel(v *viper.Viper) (zapcore.Level, error) {
 	var lvl zapcore.Level
 	lvlStr := v.GetString(cfgLoggerLevel)