Enhance LangChain GenAI semconv tracing

instrumentation-genai/opentelemetry-instrumentation-langchain/CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- Enhanced the LangChain instrumentor with semconv-aligned model, agent,
+  workflow, tool, and retriever tracing plus richer event and W3C propagation
+  handling. ([#4389](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4389))
 - Added span support for genAI langchain llm invocation.
   ([#3665](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3665))
 - Added support to call genai utils handler for langchain LLM invocations.

instrumentation-genai/opentelemetry-instrumentation-langchain/src/opentelemetry/instrumentation/langchain/__init__.py

@@ -45,8 +45,13 @@
 from opentelemetry.instrumentation.langchain.callback_handler import (
     OpenTelemetryLangChainCallbackHandler,
 )
+from opentelemetry.instrumentation.langchain.event_emitter import EventEmitter
 from opentelemetry.instrumentation.langchain.package import _instruments
+from opentelemetry.instrumentation.langchain.span_manager import _SpanManager
+from opentelemetry.instrumentation.langchain.version import __version__
 from opentelemetry.instrumentation.utils import unwrap
+from opentelemetry.semconv.schemas import Schemas
+from opentelemetry.trace import get_tracer
 from opentelemetry.util.genai.handler import get_telemetry_handler
 
 
@@ -78,8 +83,20 @@ def _instrument(self, **kwargs: Any):
             meter_provider=meter_provider,
             logger_provider=logger_provider,
         )
+
+        span_manager = _SpanManager(
+            tracer=get_tracer(
+                __name__,
+                __version__,
+                tracer_provider,
+                schema_url=Schemas.V1_37_0.value,
+            ),
+        )
+
         otel_callback_handler = OpenTelemetryLangChainCallbackHandler(
             telemetry_handler=telemetry_handler,
+            span_manager=span_manager,
+            event_emitter=EventEmitter(logger_provider=logger_provider),
         )
 
         wrap_function_wrapper(