chore(config/tracer): migrate tracingAsTransport

ddtrace/tracer/log.go

@@ -130,7 +130,7 @@ func logStartup(t *tracer) {
 		Env:                         t.config.env,
 		Service:                     t.config.serviceName,
 		AgentURL:                    agentURL,
-		Debug:                       t.config.debug,
+		Debug:                       t.config.internalConfig.Debug(),
 		AnalyticsEnabled:            !math.IsNaN(globalconfig.AnalyticsRate()),
 		SampleRate:                  fmt.Sprintf("%f", t.rulesSampling.traces.globalRate),
 		SampleRateLimit:             "disabled",
@@ -155,7 +155,7 @@ func logStartup(t *tracer) {
 		FeatureFlags:                featureFlags,
 		PropagationStyleInject:      injectorNames,
 		PropagationStyleExtract:     extractorNames,
-		TracingAsTransport:          t.config.tracingAsTransport,
+		TracingAsTransport:          t.config.internalConfig.TracingAsTransport(),
 		DogstatsdAddr:               t.config.dogstatsdAddr,
 		DataStreamsEnabled:          t.config.dataStreamsMonitoringEnabled,
 	}

ddtrace/tracer/option.go

@@ -141,8 +141,8 @@ const (
 
 // config holds the tracer configuration.
 type config struct {
-	// debug, when true, writes details to logs.
-	debug bool
+	// internalConfig holds a reference to the global configuration singleton.
+	internalConfig *internalconfig.Config
 
 	// appsecStartOptions controls the options used when starting appsec features.
 	appsecStartOptions []appsecconfig.StartOption
@@ -328,9 +328,6 @@ type config struct {
 	// logDirectory is directory for tracer logs specified by user-setting DD_TRACE_LOG_DIRECTORY. default empty/unused
 	logDirectory string
 
-	// tracingAsTransport specifies whether the tracer is running in transport-only mode, where traces are only sent when other products request it.
-	tracingAsTransport bool
-
 	// traceRateLimitPerSecond specifies the rate limit for traces.
 	traceRateLimitPerSecond float64
 
@@ -379,7 +376,7 @@ const partialFlushMinSpansDefault = 1000
 // and passed user opts.
 func newConfig(opts ...StartOption) (*config, error) {
 	c := new(config)
-	internalConfig := internalconfig.Get()
+	c.internalConfig = internalconfig.Get()
 
 	// If this was built with a recent-enough version of Orchestrion, force the orchestrion config to
 	// the baked-in values. We do this early so that opts can be used to override the baked-in values,
@@ -482,7 +479,6 @@ func newConfig(opts ...StartOption) (*config, error) {
 	c.logStartup = internal.BoolEnv("DD_TRACE_STARTUP_LOGS", true)
 	c.runtimeMetrics = internal.BoolVal(getDDorOtelConfig("metrics"), false)
 	c.runtimeMetricsV2 = internal.BoolEnv("DD_RUNTIME_METRICS_V2_ENABLED", true)
-	c.debug = internalConfig.Debug()
 	c.logDirectory = env.Get("DD_TRACE_LOG_DIRECTORY")
 	c.enabled = newDynamicConfig("tracing_enabled", internal.BoolVal(getDDorOtelConfig("enabled"), true), func(_ bool) bool { return true }, equal[bool])
 	if _, ok := env.Lookup("DD_TRACE_ENABLED"); ok {
@@ -613,7 +609,7 @@ func newConfig(opts ...StartOption) (*config, error) {
 	if c.logger != nil {
 		log.UseLogger(c.logger)
 	}
-	if c.debug {
+	if c.internalConfig.Debug() {
 		log.SetLevel(log.LevelDebug)
 	}
 	// Check if CI Visibility mode is enabled
@@ -692,7 +688,7 @@ func apmTracingDisabled(c *config) {
 	// to let the backend know that it needs to keep APM UI disabled.
 	c.globalSampleRate = 1.0
 	c.traceRateLimitPerSecond = 1.0 / 60
-	c.tracingAsTransport = true
+	c.internalConfig.SetTracingAsTransport(true)
 	WithGlobalTag("_dd.apm.enabled", 0)(c)
 	// Disable runtime metrics. In `tracingAsTransport` mode, we'll still
 	// tell the agent we computed them, so it doesn't do it either.
@@ -1009,8 +1005,7 @@ func WithDebugStack(enabled bool) StartOption {
 // WithDebugMode enables debug mode on the tracer, resulting in more verbose logging.
 func WithDebugMode(enabled bool) StartOption {
 	return func(c *config) {
-		telemetry.RegisterAppConfig("trace_debug_enabled", enabled, telemetry.OriginCode)
-		c.debug = enabled
+		c.internalConfig.SetDebug(enabled, telemetry.OriginCode)
 	}
 }
 

ddtrace/tracer/option_test.go

@@ -26,7 +26,6 @@ import (
 
 	"github.com/DataDog/dd-trace-go/v2/ddtrace/ext"
 	"github.com/DataDog/dd-trace-go/v2/internal"
-	internalconfig "github.com/DataDog/dd-trace-go/v2/internal/config"
 	"github.com/DataDog/dd-trace-go/v2/internal/globalconfig"
 	"github.com/DataDog/dd-trace-go/v2/internal/log"
 	"github.com/DataDog/dd-trace-go/v2/internal/telemetry"
@@ -375,7 +374,7 @@ func TestTracerOptionsDefaults(t *testing.T) {
 		assert.Equal(x.Timeout, y.Timeout)
 		compareHTTPClients(t, x, y)
 		assert.True(getFuncName(x.Transport.(*http.Transport).DialContext) == getFuncName(internal.DefaultDialer(30*time.Second).DialContext))
-		assert.False(c.debug)
+		assert.False(c.internalConfig.Debug())
 	})
 
 	t.Run("http-client", func(t *testing.T) {
@@ -430,48 +429,43 @@ func TestTracerOptionsDefaults(t *testing.T) {
 			assert.NoError(t, err)
 			defer tracer.Stop()
 			c := tracer.config
-			assert.True(t, c.debug)
+			assert.True(t, c.internalConfig.Debug())
 		})
 		t.Run("env", func(t *testing.T) {
 			t.Setenv("DD_TRACE_DEBUG", "true")
-			internalconfig.ResetForTesting()
 			c, err := newTestConfig()
 			assert.NoError(t, err)
-			assert.True(t, c.debug)
+			assert.True(t, c.internalConfig.Debug())
 		})
 		t.Run("otel-env-debug", func(t *testing.T) {
 			t.Setenv("OTEL_LOG_LEVEL", "debug")
-			internalconfig.ResetForTesting()
 			c, err := newTestConfig()
 			assert.NoError(t, err)
-			assert.True(t, c.debug)
+			assert.True(t, c.internalConfig.Debug())
 		})
 		t.Run("otel-env-notdebug", func(t *testing.T) {
 			// any value other than debug, does nothing
 			t.Setenv("OTEL_LOG_LEVEL", "notdebug")
-			internalconfig.ResetForTesting()
 			c, err := newTestConfig()
 			assert.NoError(t, err)
-			assert.False(t, c.debug)
+			assert.False(t, c.internalConfig.Debug())
 		})
 		t.Run("override-chain", func(t *testing.T) {
 			assert := assert.New(t)
 			// option override otel
 			t.Setenv("OTEL_LOG_LEVEL", "debug")
-			internalconfig.ResetForTesting()
 			c, err := newTestConfig(WithDebugMode(false))
 			assert.NoError(err)
-			assert.False(c.debug)
+			assert.False(c.internalConfig.Debug())
 			// env override otel
 			t.Setenv("DD_TRACE_DEBUG", "false")
-			internalconfig.ResetForTesting()
 			c, err = newTestConfig()
 			assert.NoError(err)
-			assert.False(c.debug)
+			assert.False(c.internalConfig.Debug())
 			// option override env
 			c, err = newTestConfig(WithDebugMode(true))
 			assert.NoError(err)
-			assert.True(c.debug)
+			assert.True(c.internalConfig.Debug())
 		})
 	})
 
@@ -745,7 +739,7 @@ func TestTracerOptionsDefaults(t *testing.T) {
 		assert.NotNil(c.globalTags.get())
 		assert.Equal("v", c.globalTags.get()["k"])
 		assert.Equal("testEnv", c.env)
-		assert.True(c.debug)
+		assert.True(c.internalConfig.Debug())
 	})
 
 	t.Run("env-tags", func(t *testing.T) {

ddtrace/tracer/telemetry_test.go

@@ -67,7 +67,7 @@ func TestTelemetryEnabled(t *testing.T) {
 		defer globalconfig.SetServiceName("")
 		defer Stop()
 
-		telemetrytest.CheckConfig(t, telemetryClient.Configuration, "trace_debug_enabled", true)
+		telemetrytest.CheckConfig(t, telemetryClient.Configuration, "DD_TRACE_DEBUG", true)
 		telemetrytest.CheckConfig(t, telemetryClient.Configuration, "service", "test-serv")
 		telemetrytest.CheckConfig(t, telemetryClient.Configuration, "env", "test-env")
 		telemetrytest.CheckConfig(t, telemetryClient.Configuration, "runtime_metrics_enabled", true)

ddtrace/tracer/tracer.go

@@ -560,7 +560,7 @@ func (t *tracer) worker(tick <-chan time.Time) {
 			t.statsd.Incr("datadog.tracer.flush_triggered", []string{"reason:invoked"}, 1)
 			t.traceWriter.flush()
 			t.statsd.Flush()
-			if !t.config.tracingAsTransport {
+			if !t.config.internalConfig.TracingAsTransport() {
 				t.stats.flushAndSend(time.Now(), withCurrentBucket)
 			}
 			// TODO(x): In reality, the traceWriter.flush() call is not synchronous
@@ -905,7 +905,7 @@ func (t *tracer) Inject(ctx *SpanContext, carrier interface{}) error {
 		return nil
 	}
 
-	if t.config.tracingAsTransport {
+	if t.config.internalConfig.TracingAsTransport() {
 		// in tracing as transport mode, only propagate when there is an upstream appsec event
 		if ctx.trace != nil &&
 			!globalinternal.VerifyTraceSourceEnabled(ctx.trace.propagatingTag(keyPropagatedTraceSource), globalinternal.ASMTraceSource) {
@@ -952,7 +952,7 @@ func (t *tracer) Extract(carrier interface{}) (*SpanContext, error) {
 		return nil, nil
 	}
 	ctx, err := t.config.propagator.Extract(carrier)
-	if t.config.tracingAsTransport && ctx != nil {
+	if t.config.internalConfig.TracingAsTransport() && ctx != nil {
 		// in tracing as transport mode, reset upstream sampling decision to make sure we keep 1 trace/minute
 		if ctx.trace != nil &&
 			!globalinternal.VerifyTraceSourceEnabled(ctx.trace.propagatingTag(keyPropagatedTraceSource), globalinternal.ASMTraceSource) {
@@ -981,7 +981,7 @@ func (t *tracer) TracerConf() TracerConf {
 		EnvTag:               t.config.env,
 		VersionTag:           t.config.version,
 		ServiceTag:           t.config.serviceName,
-		TracingAsTransport:   t.config.tracingAsTransport,
+		TracingAsTransport:   t.config.internalConfig.TracingAsTransport(),
 		isLambdaFunction:     t.config.isLambdaFunction,
 	}
 }

ddtrace/tracer/tracer_test.go

@@ -31,6 +31,7 @@ import (
 	"github.com/DataDog/dd-trace-go/v2/ddtrace/ext"
 	"github.com/DataDog/dd-trace-go/v2/ddtrace/internal/tracerstats"
 	"github.com/DataDog/dd-trace-go/v2/internal"
+	internalconfig "github.com/DataDog/dd-trace-go/v2/internal/config"
 	"github.com/DataDog/dd-trace-go/v2/internal/globalconfig"
 	"github.com/DataDog/dd-trace-go/v2/internal/log"
 	"github.com/DataDog/dd-trace-go/v2/internal/remoteconfig"
@@ -74,6 +75,8 @@ var (
 )
 
 func TestMain(m *testing.M) {
+	internalconfig.SetUseFreshConfig(true)
+	// defer internalconfig.SetUseFreshConfig(false)
 	if internal.BoolEnv("DD_APPSEC_ENABLED", false) {
 		// things are slower with AppSec; double wait times
 		timeMultiplicator = time.Duration(2)

internal/config/config.go

@@ -9,15 +9,33 @@ import (
 	"net/url"
 	"sync"
 	"time"
+
+	"github.com/DataDog/dd-trace-go/v2/internal/telemetry"
 )
 
 var (
-	instance   *config
-	configOnce sync.Once
+	useFreshConfig bool
+	instance       *Config
+	// mu protects instance and useFreshConfig
+	mu sync.Mutex
+)
+
+// Origin represents where a configuration value came from.
+// Re-exported so callers don't need to import internal/telemetry.
+type Origin = telemetry.Origin
+
+// Re-exported origin constants for common configuration sources
+const (
+	OriginCode       = telemetry.OriginCode
+	OriginCalculated = telemetry.OriginCalculated
 )
 
 // Config represents global configuration properties.
-type config struct {
+// Config instances should be obtained via Get() which always returns a non-nil value.
+// Methods on Config assume a non-nil receiver and will panic if called on nil.
+type Config struct {
+	mu sync.RWMutex
+	// Config fields are protected by the mutex.
 	agentURL                      *url.URL
 	debug                         bool
 	logStartup                    bool
@@ -45,12 +63,14 @@ type config struct {
 	ciVisibilityAgentless         bool
 	logDirectory                  string
 	traceRateLimitPerSecond       float64
+	// tracingAsTransport specifies whether the tracer is running in transport-only mode, where traces are only sent when other products request it.
+	tracingAsTransport bool
 }
 
 // loadConfig initializes and returns a new config by reading from all configured sources.
 // This function is NOT thread-safe and should only be called once through Get's sync.Once.
-func loadConfig() *config {
-	cfg := new(config)
+func loadConfig() *Config {
+	cfg := new(Config)
 
 	// TODO: Use defaults from config json instead of hardcoding them here
 	cfg.agentURL = provider.getURL("DD_TRACE_AGENT_URL", &url.URL{Scheme: "http", Host: "localhost:8126"})
@@ -80,6 +100,7 @@ func loadConfig() *config {
 	cfg.ciVisibilityAgentless = provider.getBool("DD_CIVISIBILITY_AGENTLESS_ENABLED", false)
 	cfg.logDirectory = provider.getString("DD_TRACE_LOG_DIRECTORY", "")
 	cfg.traceRateLimitPerSecond = provider.getFloat("DD_TRACE_RATE_LIMIT", 0.0)
+	cfg.tracingAsTransport = false // TODO: Report telemetry?
 
 	return cfg
 }
@@ -88,13 +109,44 @@ func loadConfig() *config {
 // This function is thread-safe and can be called from multiple goroutines concurrently.
 // The configuration is lazily initialized on first access using sync.Once, ensuring
 // loadConfig() is called exactly once even under concurrent access.
-func Get() *config {
-	configOnce.Do(func() {
+func Get() *Config {
+	mu.Lock()
+	defer mu.Unlock()
+	if useFreshConfig || instance == nil {
 		instance = loadConfig()
-	})
+	}
+
 	return instance
 }
 
-func (c *config) Debug() bool {
+func SetUseFreshConfig(use bool) {
+	mu.Lock()
+	defer mu.Unlock()
+	useFreshConfig = use
+}
+
+func (c *Config) Debug() bool {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
 	return c.debug
 }
+
+func (c *Config) SetDebug(enabled bool, origin telemetry.Origin) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.debug = enabled
+	telemetry.RegisterAppConfig("DD_TRACE_DEBUG", enabled, origin)
+}
+
+func (c *Config) TracingAsTransport() bool {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.tracingAsTransport
+}
+
+func (c *Config) SetTracingAsTransport(enabled bool) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.tracingAsTransport = enabled
+	// TODO: Report telemetry?
+}