add link_span method

ddtrace/llmobs/_llmobs.py

@@ -123,6 +123,7 @@
 from ddtrace.llmobs.types import _Meta
 from ddtrace.llmobs.types import _MetaIO
 from ddtrace.llmobs.types import _SpanField
+from ddtrace.llmobs.types import _SpanLink
 from ddtrace.llmobs.utils import Documents
 from ddtrace.llmobs.utils import Messages
 from ddtrace.llmobs.utils import extract_tool_definitions
@@ -2072,6 +2073,30 @@ def activate_distributed_headers(cls, request_headers: Dict[str, str]) -> None:
         context = HTTPPropagator.extract(request_headers)
         cls._instance.tracer.context_provider.activate(context)
         cls._instance._activate_llmobs_distributed_context(request_headers, context, _soft_fail=False)
+
+    @classmethod
+    def link_span(cls, span: Span, exported_span: ExportedLLMObsSpan, attributes: Dict[str, str] = None) -> None:
+        """
+        Links the exported_span to the provided active span, including the provided attributes
+        on the span link. Defaults to an output to input span link unless otherwise specified.
+        """
+        if cls.enabled is False:
+            return
+        if not attributes:
+            attributes = {}
+        if not attributes.get("from"):
+            attributes["from"] = "output"
+        if not attributes.get("to"):
+            attributes["to"] = "input"
+        span_link = _SpanLink(
+            span_id=exported_span["span_id"],
+            trace_id=exported_span["trace_id"],
+            attributes=attributes,
+        )
+        current_span_links = span._get_ctx_item(SPAN_LINKS) or []
+        current_span_links.append(span_link)
+        span._set_ctx_item(SPAN_LINKS, current_span_links)
+
 
 
 # initialize the default llmobs instance