Update V2 Tracer (#4193)

- Update the RunCreate object to work with recent changes
- Add optional Example ID to the tracer
- Adjust default persist_session behavior to attempt to load the session
if it exists
- Raise more useful HTTP errors for logging
- Add unit testing
- Fix the default ID to be a UUID for v2 tracer sessions


Broken out from the big draft here:
https://github.com/hwchase17/langchain/pull/4061

tests/unit_tests/callbacks/tracers/test_tracer.py

@@ -18,7 +18,12 @@ from langchain.callbacks.tracers.base import (
     TracerSession,
 )
 from langchain.callbacks.tracers.langchain import LangChainTracerV2
-from langchain.callbacks.tracers.schemas import Run, TracerSessionBase, TracerSessionV2
+from langchain.callbacks.tracers.schemas import (
+    RunCreate,
+    TracerSessionBase,
+    TracerSessionV2,
+    TracerSessionV2Create,
+)
 from langchain.schema import LLMResult
 
 TEST_SESSION_ID = 2023
@@ -541,14 +546,12 @@ def sample_runs() -> Tuple[LLMRun, ChainRun, ToolRun]:
     return llm_run, chain_run, tool_run
 
 
-# Test _get_default_query_params method
 def test_get_default_query_params(lang_chain_tracer_v2: LangChainTracerV2) -> None:
     expected = {"tenant_id": "test-tenant-id"}
     result = lang_chain_tracer_v2._get_default_query_params()
     assert result == expected
 
 
-# Test load_session method
 @patch("langchain.callbacks.tracers.langchain.requests.get")
 def test_load_session(
     mock_requests_get: Mock,
@@ -577,23 +580,65 @@ def test_convert_run(
     converted_chain_run = lang_chain_tracer_v2._convert_run(chain_run)
     converted_tool_run = lang_chain_tracer_v2._convert_run(tool_run)
 
-    assert isinstance(converted_llm_run, Run)
-    assert isinstance(converted_chain_run, Run)
-    assert isinstance(converted_tool_run, Run)
+    assert isinstance(converted_llm_run, RunCreate)
+    assert isinstance(converted_chain_run, RunCreate)
+    assert isinstance(converted_tool_run, RunCreate)
 
 
-@patch("langchain.callbacks.tracers.langchain.requests.post")
 def test_persist_run(
-    mock_requests_post: Mock,
     lang_chain_tracer_v2: LangChainTracerV2,
     sample_tracer_session_v2: TracerSessionV2,
     sample_runs: Tuple[LLMRun, ChainRun, ToolRun],
 ) -> None:
-    mock_requests_post.return_value.raise_for_status.return_value = None
-    lang_chain_tracer_v2.session = sample_tracer_session_v2
-    llm_run, chain_run, tool_run = sample_runs
-    lang_chain_tracer_v2._persist_run(llm_run)
-    lang_chain_tracer_v2._persist_run(chain_run)
-    lang_chain_tracer_v2._persist_run(tool_run)
+    """Test that persist_run method calls requests.post once per method call."""
+    with patch("langchain.callbacks.tracers.langchain.requests.post") as post, patch(
+        "langchain.callbacks.tracers.langchain.requests.get"
+    ) as get:
+        post.return_value.raise_for_status.return_value = None
+        lang_chain_tracer_v2.session = sample_tracer_session_v2
+        llm_run, chain_run, tool_run = sample_runs
+        lang_chain_tracer_v2._persist_run(llm_run)
+        lang_chain_tracer_v2._persist_run(chain_run)
+        lang_chain_tracer_v2._persist_run(tool_run)
 
-    assert mock_requests_post.call_count == 3
+        assert post.call_count == 3
+        assert get.call_count == 0
+
+
+def test_get_session_create(lang_chain_tracer_v2: LangChainTracerV2) -> None:
+    """Test creating the 'SessionCreate' object."""
+    lang_chain_tracer_v2.tenant_id = str(_TENANT_ID)
+    session_create = lang_chain_tracer_v2._get_session_create(name="test")
+    assert isinstance(session_create, TracerSessionV2Create)
+    assert session_create.name == "test"
+    assert session_create.tenant_id == _TENANT_ID
+
+
+@patch("langchain.callbacks.tracers.langchain.requests.post")
+def test_persist_session(
+    mock_requests_post: Mock,
+    lang_chain_tracer_v2: LangChainTracerV2,
+    sample_tracer_session_v2: TracerSessionV2,
+) -> None:
+    """Test persist_session returns a TracerSessionV2 with the updated ID."""
+    session_create = TracerSessionV2Create(**sample_tracer_session_v2.dict())
+    new_id = str(uuid4())
+    mock_requests_post.return_value.json.return_value = {"id": new_id}
+    result = lang_chain_tracer_v2._persist_session(session_create)
+    assert isinstance(result, TracerSessionV2)
+    res = sample_tracer_session_v2.dict()
+    res["id"] = UUID(new_id)
+    assert result.dict() == res
+
+
+@patch("langchain.callbacks.tracers.langchain.LangChainTracerV2.load_session")
+def test_load_default_session(
+    mock_load_session: Mock,
+    lang_chain_tracer_v2: LangChainTracerV2,
+    sample_tracer_session_v2: TracerSessionV2,
+) -> None:
+    """Test load_default_session attempts to load with the default name."""
+    mock_load_session.return_value = sample_tracer_session_v2
+    result = lang_chain_tracer_v2.load_default_session()
+    assert result == sample_tracer_session_v2
+    mock_load_session.assert_called_with("default")