feat(tracing): Introduce span.SetContext (#599)

otel/span_processor.go

@@ -133,8 +133,7 @@ func updateTransactionWithOtelData(transaction *sentry.Span, s otelSdkTrace.Read
 		resource[kv.Key] = kv.Value.AsString()
 	}
 
-	// TODO(michi) We might need to set this somewhere else than on the scope
-	hub.Scope().SetContext("otel", map[string]interface{}{
+	transaction.SetContext("otel", map[string]interface{}{
 		"attributes": attributes,
 		"resource":   resource,
 	})

tracing.go

@@ -52,6 +52,8 @@ type Span struct { //nolint: maligned // prefer readability over optimal memory
 	isTransaction bool
 	// recorder stores all spans in a transaction. Guaranteed to be non-nil.
 	recorder *spanRecorder
+	// span context, can only be set on transactions
+	contexts map[string]Context
 }
 
 // TraceParentContext describes the context of a (remote) parent span.
@@ -107,7 +109,10 @@ func StartSpan(ctx context.Context, operation string, options ...SpanOption) *Sp
 		ctx:           context.WithValue(ctx, spanContextKey{}, &span),
 		parent:        parent,
 		isTransaction: !hasParent,
+
+		contexts: make(map[string]Context),
 	}
+
 	if hasParent {
 		span.TraceID = parent.TraceID
 	} else {
@@ -236,6 +241,10 @@ func (s *Span) SetData(name, value string) {
 	s.Data[name] = value
 }
 
+func (s *Span) SetContext(key string, value Context) {
+	s.contexts[key] = value
+}
+
 // IsTransaction checks if the given span is a transaction.
 func (s *Span) IsTransaction() bool {
 	return s.isTransaction
@@ -484,17 +493,21 @@ func (s *Span) toEvent() *Event {
 		s.dynamicSamplingContext = DynamicSamplingContextFromTransaction(s)
 	}
 
+	contexts := map[string]Context{}
+	for k, v := range s.contexts {
+		contexts[k] = v
+	}
+	contexts["trace"] = s.traceContext().Map()
+
 	return &Event{
 		Type:        transactionType,
 		Transaction: hub.Scope().Transaction(),
-		Contexts: map[string]Context{
-			"trace": s.traceContext().Map(),
-		},
-		Tags:      s.Tags,
-		Extra:     s.Data,
-		Timestamp: s.EndTime,
-		StartTime: s.StartTime,
-		Spans:     finished,
+		Contexts:    contexts,
+		Tags:        s.Tags,
+		Extra:       s.Data,
+		Timestamp:   s.EndTime,
+		StartTime:   s.StartTime,
+		Spans:       finished,
 		TransactionInfo: &TransactionInfo{
 			Source: s.Source,
 		},

tracing_test.go

@@ -260,6 +260,7 @@ func TestStartTransaction(t *testing.T) {
 			s.StartTime = startTime
 			s.EndTime = endTime
 			s.Data = data
+			s.SetContext("otel", Context{"k": "v"})
 		},
 	)
 	transaction.Finish()
@@ -283,6 +284,7 @@ func TestStartTransaction(t *testing.T) {
 				Description: description,
 				Status:      status,
 			}.Map(),
+			"otel": {"k": "v"},
 		},
 		Tags: nil,
 		// TODO(tracing): the root span / transaction data field is
@@ -834,3 +836,36 @@ func TestToBaggage(t *testing.T) {
 		"sentry-trace_id=f1a4c5c9071eca1cdf04e4132527ed16,sentry-release=test-release,sentry-transaction=transaction-name",
 	)
 }
+
+func TestSpanSetContext(t *testing.T) {
+	ctx := NewTestContext(ClientOptions{
+		EnableTracing: true,
+	})
+	transaction := StartTransaction(ctx, "Test Transaction")
+
+	transaction.SetContext("a", Context{"b": 1})
+
+	assertEqual(t, map[string]Context{"a": {"b": 1}}, transaction.contexts)
+}
+
+func TestSpanSetContextMerges(t *testing.T) {
+	ctx := NewTestContext(ClientOptions{
+		EnableTracing: true,
+	})
+	transaction := StartTransaction(ctx, "Test Transaction")
+	transaction.SetContext("a", Context{"foo": "bar"})
+	transaction.SetContext("b", Context{"b": 2})
+
+	assertEqual(t, map[string]Context{"a": {"foo": "bar"}, "b": {"b": 2}}, transaction.contexts)
+}
+
+func TestSpanSetContextOverrides(t *testing.T) {
+	ctx := NewTestContext(ClientOptions{
+		EnableTracing: true,
+	})
+	transaction := StartTransaction(ctx, "Test Transaction")
+	transaction.SetContext("a", Context{"foo": "bar"})
+	transaction.SetContext("a", Context{"foo": 2})
+
+	assertEqual(t, map[string]Context{"a": {"foo": 2}}, transaction.contexts)
+}