Allow to configure sampling config for logs

Fixes open-telemetry#4554

Signed-off-by: Bogdan <[email protected]>

.chloggen/allowsampling.yaml

@@ -0,0 +1,11 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: service/telemetry
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Allow to configure sampling config for logs.
+
+# One or more tracking issues or pull requests related to the change
+issues: [4554]

service/config_provider_test.go

@@ -59,9 +59,13 @@ var configNop = &Config{
 		},
 		Telemetry: telemetry.Config{
 			Logs: telemetry.LogsConfig{
-				Level:             zapcore.InfoLevel,
-				Development:       false,
-				Encoding:          "console",
+				Level:       zapcore.InfoLevel,
+				Development: false,
+				Encoding:    "console",
+				Sampling: &telemetry.LogsSamplingConfig{
+					Initial:    100,
+					Thereafter: 100,
+				},
 				OutputPaths:       []string{"stderr"},
 				ErrorOutputPaths:  []string{"stderr"},
 				DisableCaller:     false,

service/telemetry/config.go

@@ -61,6 +61,9 @@ type LogsConfig struct {
 	// (default = false)
 	DisableStacktrace bool `mapstructure:"disable_stacktrace"`
 
+	// Sampling sets a sampling policy. A nil SamplingConfig disables sampling.
+	Sampling *LogsSamplingConfig `mapstructure:"sampling"`
+
 	// OutputPaths is a list of URLs or file paths to write logging output to.
 	// The URLs could only be with "file" schema or without schema.
 	// The URLs with "file" schema must be an absolute path.
@@ -91,6 +94,14 @@ type LogsConfig struct {
 	InitialFields map[string]interface{} `mapstructure:"initial_fields"`
 }
 
+// LogsSamplingConfig sets a sampling strategy for the logger. Sampling caps the
+// global CPU and I/O load that logging puts on your process while attempting
+// to preserve a representative subset of your logs.
+type LogsSamplingConfig struct {
+	Initial    int `mapstructure:"initial"`
+	Thereafter int `mapstructure:"thereafter"`
+}
+
 // MetricsConfig exposes the common Telemetry configuration for one component.
 // Experimental: *NOTE* this structure is subject to change or removal in the future.
 type MetricsConfig struct {

service/telemetry/telemetry.go

@@ -73,12 +73,9 @@ func New(_ context.Context, set Settings, cfg Config) (*Telemetry, error) {
 func newLogger(cfg LogsConfig, options []zap.Option) (*zap.Logger, error) {
 	// Copied from NewProductionConfig.
 	zapCfg := &zap.Config{
-		Level:       zap.NewAtomicLevelAt(cfg.Level),
-		Development: cfg.Development,
-		Sampling: &zap.SamplingConfig{
-			Initial:    100,
-			Thereafter: 100,
-		},
+		Level:             zap.NewAtomicLevelAt(cfg.Level),
+		Development:       cfg.Development,
+		Sampling:          toSamplingConfig(cfg.Sampling),
 		Encoding:          cfg.Encoding,
 		EncoderConfig:     zap.NewProductionEncoderConfig(),
 		OutputPaths:       cfg.OutputPaths,
@@ -101,9 +98,18 @@ func newLogger(cfg LogsConfig, options []zap.Option) (*zap.Logger, error) {
 	return logger, nil
 }
 
-type nopSpanProcessor struct {
+func toSamplingConfig(sc *LogsSamplingConfig) *zap.SamplingConfig {
+	if sc == nil {
+		return nil
+	}
+	return &zap.SamplingConfig{
+		Initial:    sc.Initial,
+		Thereafter: sc.Thereafter,
+	}
 }
 
+type nopSpanProcessor struct{}
+
 func (n nopSpanProcessor) OnStart(context.Context, sdktrace.ReadWriteSpan) {}
 
 func (n nopSpanProcessor) OnEnd(sdktrace.ReadOnlySpan) {}

service/unmarshaler.go

@@ -45,9 +45,13 @@ func unmarshal(v *confmap.Conf, factories component.Factories) (*configSettings,
 		Service: ConfigService{
 			Telemetry: telemetry.Config{
 				Logs: telemetry.LogsConfig{
-					Level:             zapcore.InfoLevel,
-					Development:       false,
-					Encoding:          "console",
+					Level:       zapcore.InfoLevel,
+					Development: false,
+					Encoding:    "console",
+					Sampling: &telemetry.LogsSamplingConfig{
+						Initial:    100,
+						Thereafter: 100,
+					},
 					OutputPaths:       []string{"stderr"},
 					ErrorOutputPaths:  []string{"stderr"},
 					DisableCaller:     false,

service/unmarshaler_test.go

@@ -51,9 +51,13 @@ func TestUnmarshalEmptyAllSections(t *testing.T) {
 
 	zapProdCfg := zap.NewProductionConfig()
 	assert.Equal(t, telemetry.LogsConfig{
-		Level:             zapProdCfg.Level.Level(),
-		Development:       zapProdCfg.Development,
-		Encoding:          "console",
+		Level:       zapProdCfg.Level.Level(),
+		Development: zapProdCfg.Development,
+		Encoding:    "console",
+		Sampling: &telemetry.LogsSamplingConfig{
+			Initial:    100,
+			Thereafter: 100,
+		},
 		DisableCaller:     zapProdCfg.DisableCaller,
 		DisableStacktrace: zapProdCfg.DisableStacktrace,
 		OutputPaths:       zapProdCfg.OutputPaths,