[#20] Add log sampling configuration

Signed-off-by: Denis Kirillov <d.kirillov@yadro.com>

cmd/s3-lifecycler/logger.go

@@ -21,29 +21,19 @@ type Logger struct {
 }
 
 func pickLogger(v *viper.Viper) *Logger {
-	lvl, err := getLogLevel(v.GetString(cfgLoggerLevel))
-	if err != nil {
-		panic(err)
+	switch dest := v.GetString(cfgLoggerDestination); dest {
+	case destinationStdout:
+		return newStdoutLogger(v)
+	case destinationJournald:
+		return newJournaldLogger(v)
+	default:
+		panic(fmt.Sprintf("wrong destination for logger: %s", dest))
 	}
-
-	dest := v.GetString(cfgLoggerDestination)
-
-	if dest == destinationStdout {
-		return newStdoutLogger(lvl)
-	}
-
-	if dest == destinationJournald {
-		return newJournaldLogger(lvl)
-	}
-
-	panic(fmt.Sprintf("wrong destination for logger: %s", dest))
 }
 
-func newStdoutLogger(lvl zapcore.Level) *Logger {
-	c := zap.NewProductionConfig()
-	c.Level = zap.NewAtomicLevelAt(lvl)
+func newStdoutLogger(v *viper.Viper) *Logger {
+	c := newZapLogConfig(v)
 	c.Encoding = "console"
-	c.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
 
 	l, err := c.Build(
 		zap.AddStacktrace(zap.NewAtomicLevelAt(zap.FatalLevel)),
@@ -55,10 +45,8 @@ func newStdoutLogger(lvl zapcore.Level) *Logger {
 	return &Logger{logger: l, lvl: c.Level}
 }
 
-func newJournaldLogger(lvl zapcore.Level) *Logger {
-	c := zap.NewProductionConfig()
-	c.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
-	c.Level = zap.NewAtomicLevelAt(lvl)
+func newJournaldLogger(v *viper.Viper) *Logger {
+	c := newZapLogConfig(v)
 
 	// We can use NewJSONEncoder instead if, say, frontend
 	// would like to access journald logs and parse them easily.
@@ -74,6 +62,28 @@ func newJournaldLogger(lvl zapcore.Level) *Logger {
 	return &Logger{logger: l, lvl: c.Level}
 }
 
+func newZapLogConfig(v *viper.Viper) zap.Config {
+	lvl, err := getLogLevel(v.GetString(cfgLoggerLevel))
+	if err != nil {
+		panic(err)
+	}
+
+	c := zap.NewProductionConfig()
+	c.Level = zap.NewAtomicLevelAt(lvl)
+	c.EncoderConfig.EncodeTime = zapcore.ISO8601TimeEncoder
+
+	if v.GetBool(cfgLoggerSamplingEnabled) {
+		c.Sampling = &zap.SamplingConfig{
+			Initial:    v.GetInt(cfgLoggerSamplingInitial),
+			Thereafter: v.GetInt(cfgLoggerSamplingThereafter),
+		}
+	} else {
+		c.Sampling = nil
+	}
+
+	return c
+}
+
 func getLogLevel(lvlStr string) (zapcore.Level, error) {
 	var lvl zapcore.Level
 	err := lvl.UnmarshalText([]byte(lvlStr))

cmd/s3-lifecycler/settings.go

@@ -36,8 +36,11 @@ const (
 	cfgPprofAddress      = "pprof.address"
 
 	// Logger.
-	cfgLoggerLevel       = "logger.level"
-	cfgLoggerDestination = "logger.destination"
+	cfgLoggerLevel              = "logger.level"
+	cfgLoggerDestination        = "logger.destination"
+	cfgLoggerSamplingEnabled    = "logger.sampling.enabled"
+	cfgLoggerSamplingInitial    = "logger.sampling.initial"
+	cfgLoggerSamplingThereafter = "logger.sampling.thereafter"
 
 	// Morph.
 	cfgMorphRPCEndpointPrefixTmpl        = "morph.rpc_endpoint.%d."
@@ -125,6 +128,8 @@ func settings() *viper.Viper {
 	// logger:
 	v.SetDefault(cfgLoggerLevel, "info")
 	v.SetDefault(cfgLoggerDestination, "stdout")
+	v.SetDefault(cfgLoggerSamplingThereafter, 100)
+	v.SetDefault(cfgLoggerSamplingInitial, 100)
 
 	// services:
 	v.SetDefault(cfgPrometheusEnabled, false)

config/config.env

@@ -9,6 +9,9 @@ S3_LIFECYCLER_WALLET_PASSPHRASE=pwd
 # Logger
 S3_LIFECYCLER_LOGGER_LEVEL=debug
 S3_LIFECYCLER_LOGGER_DESTINATION=stdout
+S3_LIFECYCLER_LOGGER_SAMPLING_ENABLED=false
+S3_LIFECYCLER_LOGGER_SAMPLING_INITIAL=100
+S3_LIFECYCLER_LOGGER_SAMPLING_THEREAFTER=100
 
 # Metrics
 S3_LIFECYCLER_PPROF_ENABLED=false

config/config.yaml

@@ -7,6 +7,10 @@ wallet:
 logger:
   level: info # Log level.
   destination: stdout # Logging destination.
+  sampling:
+    enabled: false
+    initial: 100
+    thereafter: 100
 
 pprof:
   enabled: false

docs/configuration.md

@@ -47,14 +47,21 @@ wallet:
 
 ```yaml
 logger:
-  level: debug
+  level: info
   destination: stdout
+  sampling:
+    enabled: false
+    initial: 100
+    thereafter: 100
 ```
 
-| Parameter     | Type     | SIGHUP reload | Default value | Description                                                                          |
-|---------------|----------|---------------|---------------|--------------------------------------------------------------------------------------|
-| `level`       | `string` | yes           | `info`        | Logging level. Possible values: `debug`, `info`, `warn`, `dpanic`, `panic`, `fatal`. |
-| `destination` | `string` | no            | `stdout`      | Destination for logger: `stdout` or `journald`                                       |
+| Parameter             | Type     | SIGHUP reload | Default value | Description                                                                                      |
+|-----------------------|----------|---------------|---------------|--------------------------------------------------------------------------------------------------|
+| `level`               | `string` | yes           | `info`        | Logging level. Possible values: `debug`, `info`, `warn`, `dpanic`, `panic`, `fatal`.             |
+| `destination`         | `string` | no            | `stdout`      | Destination for logger: `stdout` or `journald`                                                   |
+| `sampling.enabled`    | `bool`   | no            | `false`       | Enable sampling.                                                                                 |
+| `sampling.initial`    | `int`    | no            | `100`         | Logs firth N of the same (level and message) log entries each second.                            |
+| `sampling.thereafter` | `int`    | no            | `100`         | Logs every Mth of the same (level and message) log entries after first N entries in that second. |
 
 # `pprof` section