config: set default tracing sample rate to 1.0 (#5422)

The previous default sample rate of 0.0001 is very low, so traces are
unlikely to be visible after enabling them until many thousands of
requests have been sent. This could be confusing to users.

config/envoyconfig/listeners_main.go

@@ -187,6 +187,10 @@ func (b *Builder) buildMainHTTPConnectionManagerFilter(
 		return nil, err
 	}
 
+	sampleRate := 1.0
+	if cfg.Options.TracingSampleRate != nil {
+		sampleRate = *cfg.Options.TracingSampleRate
+	}
 	mgr := &envoy_extensions_filters_network_http_connection_manager.HttpConnectionManager{
 		AlwaysSetRequestIdInResponse: true,
 		StatPrefix:                   "ingress",
@@ -199,7 +203,7 @@ func (b *Builder) buildMainHTTPConnectionManagerFilter(
 		HttpProtocolOptions: http1ProtocolOptions,
 		RequestTimeout:      durationpb.New(cfg.Options.ReadTimeout),
 		Tracing: &envoy_extensions_filters_network_http_connection_manager.HttpConnectionManager_Tracing{
-			RandomSampling: &envoy_type_v3.Percent{Value: cfg.Options.TracingSampleRate * 100},
+			RandomSampling: &envoy_type_v3.Percent{Value: max(0.0, min(1.0, sampleRate)) * 100},
 			Provider:       tracingProvider,
 		},
 		// See https://www.envoyproxy.io/docs/envoy/latest/configuration/http/http_conn_man/headers#x-forwarded-for

config/envoyconfig/testdata/main_http_connection_manager_filter.json

@@ -52,7 +52,9 @@
             },
             "timeout": "10s"
           },
-          "metadataContextNamespaces": ["com.pomerium.client-certificate-info"],
+          "metadataContextNamespaces": [
+            "com.pomerium.client-certificate-info"
+          ],
           "statusOnError": {
             "code": "InternalServerError"
           },
@@ -180,7 +182,7 @@
     "statPrefix": "ingress",
     "tracing": {
       "randomSampling": {
-        "value": 0.01
+        "value": 100
       }
     },
     "useRemoteAddress": true,

config/options.go

@@ -211,8 +211,8 @@ type Options struct {
 	MetricsClientCAFile       string `mapstructure:"metrics_client_ca_file" yaml:"metrics_client_ca_file,omitempty"`
 
 	// Tracing shared settings
-	TracingProvider   string  `mapstructure:"tracing_provider" yaml:"tracing_provider,omitempty"`
-	TracingSampleRate float64 `mapstructure:"tracing_sample_rate" yaml:"tracing_sample_rate,omitempty"`
+	TracingProvider   string   `mapstructure:"tracing_provider" yaml:"tracing_provider,omitempty"`
+	TracingSampleRate *float64 `mapstructure:"tracing_sample_rate" yaml:"tracing_sample_rate,omitempty"`
 
 	// Datadog tracing address
 	TracingDatadogAddress string `mapstructure:"tracing_datadog_address" yaml:"tracing_datadog_address,omitempty"`
@@ -317,7 +317,6 @@ var defaultOptions = Options{
 	GRPCAddr:                 ":443",
 	GRPCClientTimeout:        10 * time.Second, // Try to withstand transient service failures for a single request
 	AuthenticateCallbackPath: "/oauth2/callback",
-	TracingSampleRate:        0.0001,
 
 	AutocertOptions: AutocertOptions{
 		Folder: dataDir(),
@@ -1520,7 +1519,7 @@ func (o *Options) ApplySettings(ctx context.Context, certsIndex *cryptutil.Certi
 	setCertificate(&o.MetricsCertificate, &o.MetricsCertificateKey, settings.MetricsCertificate)
 	set(&o.MetricsClientCA, settings.MetricsClientCa)
 	set(&o.TracingProvider, settings.TracingProvider)
-	set(&o.TracingSampleRate, settings.TracingSampleRate)
+	setOptional(&o.TracingSampleRate, settings.TracingSampleRate)
 	set(&o.TracingDatadogAddress, settings.TracingDatadogAddress)
 	set(&o.TracingJaegerCollectorEndpoint, settings.TracingJaegerCollectorEndpoint)
 	set(&o.TracingJaegerAgentEndpoint, settings.TracingJaegerAgentEndpoint)
@@ -1610,7 +1609,7 @@ func (o *Options) ToProto() *config.Config {
 	settings.MetricsCertificate = toCertificateOrFromFile(o.MetricsCertificate, o.MetricsCertificateKey, o.MetricsCertificateFile, o.MetricsCertificateKeyFile)
 	copySrcToOptionalDest(&settings.MetricsClientCa, valueOrFromFileBase64(o.MetricsClientCA, o.MetricsClientCAFile))
 	copySrcToOptionalDest(&settings.TracingProvider, &o.TracingProvider)
-	copySrcToOptionalDest(&settings.TracingSampleRate, &o.TracingSampleRate)
+	settings.TracingSampleRate = o.TracingSampleRate
 	copySrcToOptionalDest(&settings.TracingDatadogAddress, &o.TracingDatadogAddress)
 	copySrcToOptionalDest(&settings.TracingJaegerCollectorEndpoint, &o.TracingJaegerCollectorEndpoint)
 	copySrcToOptionalDest(&settings.TracingJaegerAgentEndpoint, &o.TracingJaegerAgentEndpoint)

config/trace.go

@@ -19,11 +19,15 @@ type TracingOptions = trace.TracingOptions
 
 // NewTracingOptions builds a new TracingOptions from core Options
 func NewTracingOptions(o *Options) (*TracingOptions, error) {
+	sampleRate := 1.0
+	if o.TracingSampleRate != nil {
+		sampleRate = *o.TracingSampleRate
+	}
 	tracingOpts := TracingOptions{
 		Provider:            o.TracingProvider,
 		Service:             telemetry.ServiceName(o.Services),
 		JaegerAgentEndpoint: o.TracingJaegerAgentEndpoint,
-		SampleRate:          o.TracingSampleRate,
+		SampleRate:          sampleRate,
 	}
 
 	switch o.TracingProvider {

config/trace_test.go

@@ -25,13 +25,13 @@ func Test_NewTracingOptions(t *testing.T) {
 		{
 			"datadog_good",
 			&Options{TracingProvider: "datadog"},
-			&TracingOptions{Provider: "datadog", Service: "pomerium"},
+			&TracingOptions{Provider: "datadog", Service: "pomerium", SampleRate: 1},
 			false,
 		},
 		{
 			"jaeger_good",
 			&Options{TracingProvider: "jaeger", TracingJaegerAgentEndpoint: "foo", TracingJaegerCollectorEndpoint: "http://foo", Services: ServiceAll},
-			&TracingOptions{Provider: "jaeger", JaegerAgentEndpoint: "foo", JaegerCollectorEndpoint: &url.URL{Scheme: "http", Host: "foo"}, Service: "pomerium"},
+			&TracingOptions{Provider: "jaeger", JaegerAgentEndpoint: "foo", JaegerCollectorEndpoint: &url.URL{Scheme: "http", Host: "foo"}, Service: "pomerium", SampleRate: 1},
 			false,
 		},
 		{
@@ -43,7 +43,7 @@ func Test_NewTracingOptions(t *testing.T) {
 		{
 			"zipkin_good",
 			&Options{TracingProvider: "zipkin", ZipkinEndpoint: "https://foo/api/v1/spans", Services: ServiceAuthorize},
-			&TracingOptions{Provider: "zipkin", ZipkinEndpoint: &url.URL{Scheme: "https", Host: "foo", Path: "/api/v1/spans"}, Service: "pomerium-authorize"},
+			&TracingOptions{Provider: "zipkin", ZipkinEndpoint: &url.URL{Scheme: "https", Host: "foo", Path: "/api/v1/spans"}, Service: "pomerium-authorize", SampleRate: 1},
 			false,
 		},
 		{
@@ -118,9 +118,8 @@ func TestTraceManager(t *testing.T) {
 	defer srv2.Close()
 
 	src := NewStaticSource(&Config{Options: &Options{
-		TracingProvider:   "zipkin",
-		ZipkinEndpoint:    srv1.URL,
-		TracingSampleRate: 1,
+		TracingProvider: "zipkin",
+		ZipkinEndpoint:  srv1.URL,
 	}})
 
 	_ = NewTraceManager(ctx, src)
@@ -129,9 +128,8 @@ func TestTraceManager(t *testing.T) {
 	span.End()
 
 	src.SetConfig(ctx, &Config{Options: &Options{
-		TracingProvider:   "zipkin",
-		ZipkinEndpoint:    srv2.URL,
-		TracingSampleRate: 1,
+		TracingProvider: "zipkin",
+		ZipkinEndpoint:  srv2.URL,
 	}})
 
 	_, span = trace.StartSpan(ctx, "Example")