[#1673] logger: Add sampling for journald logger

Signed-off-by: Dmitrii Stepanov <d.stepanov@yadro.com>

pkg/util/logger/logger.go

@@ -2,6 +2,7 @@ package logger
 
 import (
 	"fmt"
+	"time"
 
 	"git.frostfs.info/TrueCloudLab/zapjournald"
 	"github.com/ssgreg/journald"
@@ -166,7 +167,18 @@ func newJournaldLogger(prm *Prm) (*Logger, error) {
 		zapjournald.SyslogPid(),
 	})
 
-	lZap := zap.New(coreWithContext, zap.AddStacktrace(zap.NewAtomicLevelAt(zap.FatalLevel)), zap.AddCallerSkip(1))
+	var samplerOpts []zapcore.SamplerOption
+	if c.Sampling.Hook != nil {
+		samplerOpts = append(samplerOpts, zapcore.SamplerHook(c.Sampling.Hook))
+	}
+	samplingCore := zapcore.NewSamplerWithOptions(
+		coreWithContext,
+		time.Second,
+		c.Sampling.Initial,
+		c.Sampling.Thereafter,
+		samplerOpts...,
+	)
+	lZap := zap.New(samplingCore, zap.AddStacktrace(zap.NewAtomicLevelAt(zap.FatalLevel)), zap.AddCallerSkip(1))
 
 	l := &Logger{z: lZap, lvl: lvl}
 	prm._log = l