getattr for reduced cold start times (#570)

Co-authored-by: William Fu-Hinthorn <[email protected]>

python/langsmith/__init__.py

@@ -1,17 +1,47 @@
 """LangSmith Client."""
 
-from importlib import metadata
+from typing import TYPE_CHECKING, Any, List
 
-try:
-    __version__ = metadata.version(__package__)
-except metadata.PackageNotFoundError:
-    # Case where package metadata is not available.
-    __version__ = ""
+if TYPE_CHECKING:
+    from langsmith.client import Client
+    from langsmith.run_helpers import trace, traceable
+
+
+def __getattr__(name: str) -> Any:
+    if name == "__version__":
+        try:
+            from importlib import metadata
+
+            return metadata.version(__package__)
+        except metadata.PackageNotFoundError:
+            return ""
+    elif name == "Client":
+        from langsmith.client import Client
+
+        return Client
+    elif name == "RunTree":
+        from langsmith.run_trees import RunTree
+
+        return RunTree
+    elif name == "EvaluationResult":
+        from langsmith.evaluation.evaluator import EvaluationResult
+
+        return EvaluationResult
+    elif name == "RunEvaluator":
+        from langsmith.evaluation.evaluator import RunEvaluator
+
+        return RunEvaluator
+    elif name == "trace":
+        from langsmith.run_helpers import trace
+
+        return trace
+    elif name == "traceable":
+        from langsmith.run_helpers import traceable
+
+        return traceable
+
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
 
-from langsmith.client import Client
-from langsmith.evaluation.evaluator import EvaluationResult, RunEvaluator
-from langsmith.run_helpers import trace, traceable
-from langsmith.run_trees import RunTree
 
 __all__ = [
     "Client",
@@ -22,3 +52,7 @@
     "traceable",
     "trace",
 ]
+
+
+def __dir__() -> List[str]:
+    return __all__

python/langsmith/evaluation/__init__.py

@@ -1,14 +1,55 @@
 """Evaluation Helpers."""
 
-from langsmith.evaluation._runner import evaluate, evaluate_existing
-from langsmith.evaluation.evaluator import (
-    EvaluationResult,
-    EvaluationResults,
-    RunEvaluator,
-    run_evaluator,
-)
-from langsmith.evaluation.integrations._langchain import LangChainStringEvaluator
-from langsmith.evaluation.string_evaluator import StringEvaluator
+from typing import TYPE_CHECKING, Any, List
+
+if TYPE_CHECKING:
+    from typing import List
+
+    from langsmith.evaluation.evaluator import (
+        EvaluationResult,
+        EvaluationResults,
+        RunEvaluator,
+    )
+    from langsmith.evaluation.integrations._langchain import LangChainStringEvaluator
+
+
+def __getattr__(name: str) -> Any:
+    if name == "evaluate":
+        from langsmith.evaluation._runner import evaluate
+
+        return evaluate
+    elif name == "evaluate_existing":
+        from langsmith.evaluation._runner import evaluate_existing
+
+        return evaluate_existing
+    elif name == "EvaluationResult":
+        from langsmith.evaluation.evaluator import EvaluationResult
+
+        return EvaluationResult
+    elif name == "EvaluationResults":
+        from langsmith.evaluation.evaluator import EvaluationResults
+
+        return EvaluationResults
+    elif name == "RunEvaluator":
+        from langsmith.evaluation.evaluator import RunEvaluator
+
+        return RunEvaluator
+    elif name == "run_evaluator":
+        from langsmith.evaluation.evaluator import run_evaluator
+
+        return run_evaluator
+    elif name == "StringEvaluator":
+        from langsmith.evaluation.string_evaluator import StringEvaluator
+
+        return StringEvaluator
+    elif name == "LangChainStringEvaluator":
+        from langsmith.evaluation.integrations._langchain import (
+            LangChainStringEvaluator,
+        )
+
+        return LangChainStringEvaluator
+    raise AttributeError(f"module {__name__} has no attribute {name}")
+
 
 __all__ = [
     "run_evaluator",
@@ -20,3 +61,7 @@
     "evaluate_existing",
     "LangChainStringEvaluator",
 ]
+
+
+def __dir__() -> List[str]:
+    return __all__