changes to propogate baggage by open tracing bridge

Signed-off-by: Shubham Bansal <[email protected]>

CHANGELOG.md

@@ -15,6 +15,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Add a `WithNamespace` option to `go.opentelemetry.io/otel/exporters/prometheus` to allow users to prefix metrics with a namespace. (#3970)
 - The `Version` function to `go.opentelemetry.io/otel/exporters/otlp/otlpmetric` to return the OTLP metrics client version. (#3956)
 - The `Version` function to `go.opentelemetry.io/otel/exporters/otlp/otlptrace` to return the OTLP trace client version. (#3956)
+- Added baggage to propagate through opentracing bridge. (#4021)
 
 ### Changed
 

bridge/opentracing/bridge_test.go

@@ -546,3 +546,34 @@ func TestBridge_SpanContext_IsSampled(t *testing.T) {
 		})
 	}
 }
+
+func TestOTHTTPHeadersCarrier(t *testing.T) {
+	carrier := ot.HTTPHeadersCarrier{}
+	testBridgeWithCarrier(t, carrier)
+}
+
+func TestOTTextMapCarrier(t *testing.T) {
+	carrier := ot.TextMapCarrier{}
+	testBridgeWithCarrier(t, carrier)
+}
+
+func testBridgeWithCarrier(t *testing.T, carrier interface{}) {
+	mockOtelTracer := internal.NewMockTracer()
+	bridgeTracer, _ := NewTracerPair(mockOtelTracer)
+	otel.SetTextMapPropagator(propagation.TraceContext{})
+	span := bridgeTracer.StartSpan("testSpan1")
+	// adding data to baggage
+	span.SetBaggageItem("foo", "bar")
+	defer span.Finish()
+
+	err := bridgeTracer.Inject(span.Context(), ot.HTTPHeaders, carrier)
+	assert.NoError(t, err, "Inject error")
+
+	extractedSpanContext, err := bridgeTracer.Extract(ot.HTTPHeaders, carrier)
+	assert.NoError(t, err, "Extract error")
+
+	originalSpanContext := span.Context().(*bridgeSpanContext)
+	copySpanContext := *originalSpanContext
+	copySpanContext.otelSpanContext = copySpanContext.otelSpanContext.WithRemote(true)
+	assert.Equal(t, &copySpanContext, extractedSpanContext, "Extracted span context should match with original span context")
+}

propagation/trace_context.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"regexp"
 
+	"go.opentelemetry.io/otel/baggage"
 	"go.opentelemetry.io/otel/trace"
 )
 
@@ -63,6 +64,11 @@ func (tc TraceContext) Inject(ctx context.Context, carrier TextMapCarrier) {
 		sc.SpanID(),
 		flags)
 	carrier.Set(traceparentHeader, h)
+
+	bStr := baggage.FromContext(ctx).String()
+	if bStr != "" {
+		carrier.Set(baggageHeader, bStr)
+	}
 }
 
 // Extract reads tracecontext from the carrier into a returned Context.
@@ -75,7 +81,18 @@ func (tc TraceContext) Extract(ctx context.Context, carrier TextMapCarrier) cont
 	if !sc.IsValid() {
 		return ctx
 	}
-	return trace.ContextWithRemoteSpanContext(ctx, sc)
+
+	parent := trace.ContextWithRemoteSpanContext(ctx, sc)
+
+	bStr := carrier.Get(baggageHeader)
+	if bStr == "" {
+		return parent
+	}
+	bag, err := baggage.Parse(bStr)
+	if err != nil {
+		return parent
+	}
+	return baggage.ContextWithBaggage(parent, bag)
 }
 
 func (tc TraceContext) extract(carrier TextMapCarrier) trace.SpanContext {