Add IsSampled to OpenTracing bridge

bridge/opentracing/bridge.go

@@ -72,6 +72,10 @@ func (c *bridgeSpanContext) ForeachBaggageItem(handler func(k, v string) bool) {
 	}
 }
 
+func (c *bridgeSpanContext) IsSampled() bool {
+	return c.otelSpanContext.IsSampled()
+}
+
 func (c *bridgeSpanContext) setBaggageItem(restrictedKey, value string) {
 	crk := http.CanonicalHeaderKey(restrictedKey)
 	m, err := baggage.NewMember(crk, value)

bridge/opentracing/bridge_test.go

@@ -254,6 +254,10 @@ func (t *testTextMapWriter) Set(key, val string) {
 	(*t.m)[key] = val
 }
 
+type samplable interface {
+	IsSampled() bool
+}
+
 func TestBridgeTracer_ExtractAndInject(t *testing.T) {
 	bridge := NewBridgeTracer()
 	bridge.SetTextMapPropagator(new(testTextMapPropagator))
@@ -503,3 +507,35 @@ func Test_otTagsToOTelAttributesKindAndError(t *testing.T) {
 		})
 	}
 }
+
+func TestBridge_SpanContext_IsSampled(t *testing.T) {
+	testCases := []struct {
+		name     string
+		flags    trace.TraceFlags
+		expected bool
+	}{
+		{
+			name:     "not sampled",
+			flags:    0,
+			expected: false,
+		},
+		{
+			name:     "sampled",
+			flags:    trace.FlagsSampled,
+			expected: true,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			tracer := internal.NewMockTracer()
+			tracer.TraceFlags = tc.flags
+
+			b, _ := NewTracerPair(tracer)
+			s := b.StartSpan("abc")
+			sc := s.Context()
+
+			assert.Equal(t, tc.expected, sc.(samplable).IsSampled())
+		})
+	}
+}

bridge/opentracing/internal/mock.go

@@ -48,6 +48,7 @@ type MockTracer struct {
 	SpareTraceIDs         []trace.TraceID
 	SpareSpanIDs          []trace.SpanID
 	SpareContextKeyValues []MockContextKeyValue
+	TraceFlags            trace.TraceFlags
 
 	randLock sync.Mutex
 	rand     *rand.Rand
@@ -76,7 +77,7 @@ func (t *MockTracer) Start(ctx context.Context, name string, opts ...trace.SpanS
 	spanContext := trace.NewSpanContext(trace.SpanContextConfig{
 		TraceID:    t.getTraceID(ctx, &config),
 		SpanID:     t.getSpanID(),
-		TraceFlags: 0,
+		TraceFlags: t.TraceFlags,
 	})
 	span := &MockSpan{
 		mockTracer:     t,