fix(llmobs): respect configured writer timeout in _send_payload

ddtrace/llmobs/_writer.py

@@ -304,7 +304,7 @@ def periodic(self) -> None:
             )
 
     def _send_payload(self, payload: bytes, num_events: int):
-        conn = get_connection(self._intake)
+        conn = get_connection(self._intake, timeout=self._timeout)
         try:
             conn.request("POST", self._endpoint, payload, self._headers)
             resp = conn.getresponse()

releasenotes/notes/fix-llmobs-writer-respect-timeout-cd84c70e0d69e371.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    LLM Observability: Fixes an issue where the writer ignored its configured request
+    timeout (``_DD_LLMOBS_WRITER_TIMEOUT``, default 5 seconds) and instead used the 2 second
+    connection default, causing intermittent ``TimeoutError`` and dropped span and evaluation
+    metric events on high-latency connections to the agent or intake.

tests/llmobs/test_llmobs_span_agentless_writer.py

@@ -136,6 +136,18 @@ def log_message(self, *args):
     )
 
 
+@mock.patch("ddtrace.llmobs._writer.get_connection")
+def test_send_payload_uses_configured_timeout(mock_get_connection, mock_writer_logs):
+    """Regression: _send_payload must open the connection with the writer's configured
+    timeout (self._timeout), not get_connection's DEFAULT_TIMEOUT (2.0s).
+    """
+    mock_get_connection.return_value.getresponse.return_value.status = 200
+    llmobs_span_writer = LLMObsSpanWriter(1, 5.0, is_agentless=True, _site=DD_SITE, _api_key=DD_API_KEY)
+    llmobs_span_writer.enqueue(_completion_event())
+    llmobs_span_writer.periodic()
+    mock_get_connection.assert_called_once_with(llmobs_span_writer._intake, timeout=5.0)
+
+
 def test_send_completion_no_api_key(mock_writer_logs):
     with override_global_config(dict(_dd_api_key="")):
         llmobs_span_writer = LLMObsSpanWriter(interval=1, timeout=1, is_agentless=True, _site=DD_SITE, _api_key="")