send metadata with experiment spans

Author: gary-huang

ddtrace/llmobs/_constants.py

@@ -104,9 +104,12 @@
 
 PROXY_REQUEST = "llmobs.proxy_request"
 
+# experiment span baggage keys to be propagated across boundaries
 EXPERIMENT_ID_KEY = "_ml_obs.experiment_id"
 EXPERIMENT_RUN_ID_KEY = "_ml_obs.experiment_run_id"
 EXPERIMENT_RUN_ITERATION_KEY = "_ml_obs.experiment_run_iteration"
+# experiment context keys
+EXPERIMENT_RECORD_METADATA = "_ml_obs.meta.metadata"
 EXPERIMENT_EXPECTED_OUTPUT = "_ml_obs.meta.input.expected_output"
 EXPERIMENTS_INPUT = "_ml_obs.meta.input"
 EXPERIMENTS_OUTPUT = "_ml_obs.meta.output"

ddtrace/llmobs/_experiment.py

@@ -23,6 +23,7 @@
 from ddtrace.constants import ERROR_TYPE
 from ddtrace.internal.logger import get_logger
 from ddtrace.llmobs._constants import DD_SITES_NEEDING_APP_SUBDOMAIN
+from ddtrace.llmobs._constants import EXPERIMENT_RECORD_METADATA
 from ddtrace.llmobs._constants import EXPERIMENT_EXPECTED_OUTPUT
 from ddtrace.llmobs._utils import convert_tags_dict_to_list
 from ddtrace.llmobs._utils import safe_json
@@ -457,6 +458,8 @@ def _process_record(self, idx_record: Tuple[int, DatasetRecord], run: _Experimen
                 span.set_exc_info(*sys.exc_info())
             self._llmobs_instance.annotate(span, input_data=input_data, output_data=output_data, tags=tags)
             span._set_ctx_item(EXPERIMENT_EXPECTED_OUTPUT, safe_json(record["expected_output"]))
+            if "metadata" in record:
+                span._set_ctx_item(EXPERIMENT_RECORD_METADATA, record["metadata"])
             return {
                 "idx": idx,
                 "span_id": span_id,