Add possibility to extend tracer options (#173)

Author: peterdeme

ddlambda.go

@@ -18,12 +18,14 @@ import (
 	"strings"
 	"time"
 
+	"github.com/aws/aws-lambda-go/lambda"
+	"gopkg.in/DataDog/dd-trace-go.v1/ddtrace/tracer"
+
 	"github.com/DataDog/datadog-lambda-go/internal/extension"
 	"github.com/DataDog/datadog-lambda-go/internal/logger"
 	"github.com/DataDog/datadog-lambda-go/internal/metrics"
 	"github.com/DataDog/datadog-lambda-go/internal/trace"
 	"github.com/DataDog/datadog-lambda-go/internal/wrapper"
-	"github.com/aws/aws-lambda-go/lambda"
 )
 
 type (
@@ -71,6 +73,8 @@ type (
 		// TraceContextExtractor is the function that extracts a root/parent trace context from the Lambda event body.
 		// See trace.DefaultTraceExtractor for an example.
 		TraceContextExtractor trace.ContextExtractor
+		// TracerOptions are additional options passed to the tracer.
+		TracerOptions []tracer.StartOption
 	}
 )
 
@@ -214,6 +218,7 @@ func (cfg *Config) toTraceConfig() trace.Config {
 		traceConfig.DDTraceEnabled = cfg.DDTraceEnabled
 		traceConfig.MergeXrayTraces = cfg.MergeXrayTraces
 		traceConfig.TraceContextExtractor = cfg.TraceContextExtractor
+		traceConfig.TracerOptions = cfg.TracerOptions
 	}
 
 	if traceConfig.TraceContextExtractor == nil {

internal/trace/listener.go

@@ -34,6 +34,7 @@ type (
 		otelTracerEnabled        bool
 		extensionManager         *extension.ExtensionManager
 		traceContextExtractor    ContextExtractor
+		tracerOptions            []tracer.StartOption
 	}
 
 	// Config gives options for how the Listener should work
@@ -43,6 +44,7 @@ type (
 		UniversalInstrumentation bool
 		OtelTracerEnabled        bool
 		TraceContextExtractor    ContextExtractor
+		TracerOptions            []tracer.StartOption
 	}
 )
 
@@ -61,6 +63,7 @@ func MakeListener(config Config, extensionManager *extension.ExtensionManager) L
 		otelTracerEnabled:        config.OtelTracerEnabled,
 		extensionManager:         extensionManager,
 		traceContextExtractor:    config.TraceContextExtractor,
+		tracerOptions:            config.TracerOptions,
 	}
 }
 
@@ -82,12 +85,12 @@ func (l *Listener) HandlerStarted(ctx context.Context, msg json.RawMessage) cont
 			serviceName = "aws.lambda"
 		}
 		extensionNotRunning := !l.extensionManager.IsExtensionRunning()
-		opts := []tracer.StartOption{
+		opts := append([]tracer.StartOption{
 			tracer.WithService(serviceName),
 			tracer.WithLambdaMode(extensionNotRunning),
 			tracer.WithGlobalTag("_dd.origin", "lambda"),
 			tracer.WithSendRetries(2),
-		}
+		}, l.tracerOptions...)
 		if l.otelTracerEnabled {
 			provider := ddotel.NewTracerProvider(
 				opts...,