Implement better reprs for Runnables

libs/langchain/langchain/load/serializable.py

@@ -68,6 +68,13 @@ class Serializable(BaseModel, ABC):
     class Config:
         extra = "ignore"
 
+    def __repr_args__(self) -> Any:
+        return [
+            (k, v)
+            for k, v in super().__repr_args__()
+            if (k not in self.__fields__ or self.__fields__[k].get_default() != v)
+        ]
+
     _lc_kwargs = PrivateAttr(default_factory=dict)
 
     def __init__(self, **kwargs: Any) -> None:

libs/langchain/langchain/schema/runnable/base.py

@@ -59,6 +59,8 @@ from langchain.schema.runnable.utils import (
     accepts_run_manager,
     gather_with_concurrency,
     get_function_first_arg_dict_keys,
+    get_lambda_source,
+    indent_lines_after_first,
 )
 from langchain.utils.aiter import atee, py_anext
 from langchain.utils.iter import safetee
@@ -1298,6 +1300,12 @@ class RunnableSequence(Serializable, Runnable[Input, Output]):
     def output_schema(self) -> Type[BaseModel]:
         return self.last.output_schema
 
+    def __repr__(self) -> str:
+        return "\n| ".join(
+            repr(s) if i == 0 else indent_lines_after_first(repr(s), "| ")
+            for i, s in enumerate(self.steps)
+        )
+
     def __or__(
         self,
         other: Union[
@@ -1819,6 +1827,13 @@ class RunnableMap(Serializable, Runnable[Input, Dict[str, Any]]):
             **{k: (v.OutputType, None) for k, v in self.steps.items()},
         )
 
+    def __repr__(self) -> str:
+        map_for_repr = ",\n  ".join(
+            f"{k}: {indent_lines_after_first(repr(v), '  ' + k + ': ')}"
+            for k, v in self.steps.items()
+        )
+        return "{\n  " + map_for_repr + "\n}"
+
     def invoke(
         self, input: Input, config: Optional[RunnableConfig] = None
     ) -> Dict[str, Any]:
@@ -2134,7 +2149,7 @@ class RunnableLambda(Runnable[Input, Output]):
             return False
 
     def __repr__(self) -> str:
-        return "RunnableLambda(...)"
+        return f"RunnableLambda({get_lambda_source(self.func) or '...'})"
 
     def _invoke(
         self,

libs/langchain/langchain/schema/runnable/utils.py

@@ -87,6 +87,14 @@ class IsFunctionArgDict(ast.NodeVisitor):
         IsLocalDict(input_arg_name, self.keys).visit(node)
 
 
+class GetLambdaSource(ast.NodeVisitor):
+    def __init__(self) -> None:
+        self.source: Optional[str] = None
+
+    def visit_Lambda(self, node: ast.Lambda) -> Any:
+        self.source = ast.unparse(node)
+
+
 def get_function_first_arg_dict_keys(func: Callable) -> Optional[List[str]]:
     try:
         code = inspect.getsource(func)
@@ -94,5 +102,23 @@ def get_function_first_arg_dict_keys(func: Callable) -> Optional[List[str]]:
         visitor = IsFunctionArgDict()
         visitor.visit(tree)
         return list(visitor.keys) if visitor.keys else None
-    except (TypeError, OSError):
+    except (SyntaxError, TypeError, OSError):
         return None
+
+
+def get_lambda_source(func: Callable) -> Optional[str]:
+    try:
+        code = inspect.getsource(func)
+        tree = ast.parse(textwrap.dedent(code))
+        visitor = GetLambdaSource()
+        visitor.visit(tree)
+        return visitor.source
+    except (SyntaxError, TypeError, OSError):
+        return None
+
+
+def indent_lines_after_first(text: str, prefix: str) -> str:
+    n_spaces = len(prefix)
+    spaces = " " * n_spaces
+    lines = text.splitlines()
+    return "\n".join([lines[0]] + [spaces + line for line in lines[1:]])

libs/langchain/tests/unit_tests/schema/runnable/test_runnable.py

@@ -867,6 +867,7 @@ async def test_prompt_with_chat_model(
 
     chain = prompt | chat
 
+    assert repr(chain) == snapshot
     assert isinstance(chain, RunnableSequence)
     assert chain.first == prompt
     assert chain.middle == []
@@ -1350,6 +1351,7 @@ Question:
         | parser
     )
 
+    assert repr(chain) == snapshot
     assert isinstance(chain, RunnableSequence)
     assert isinstance(chain.first, RunnableMap)
     assert chain.middle == [prompt, chat]
@@ -1375,7 +1377,7 @@ Question:
             SystemMessage(content="You are a nice assistant."),
             HumanMessage(
                 content="""Context:
-[Document(page_content='foo', metadata={}), Document(page_content='bar', metadata={})]
+[Document(page_content='foo'), Document(page_content='bar')]
 
 Question:
 What is your name?"""
@@ -1413,6 +1415,7 @@ def test_seq_prompt_dict(mocker: MockerFixture, snapshot: SnapshotAssertion) ->
         }
     )
 
+    assert repr(chain) == snapshot
     assert isinstance(chain, RunnableSequence)
     assert chain.first == prompt
     assert chain.middle == [RunnableLambda(passthrough)]
@@ -2196,6 +2199,7 @@ def test_retrying(mocker: MockerFixture) -> None:
     with pytest.raises(RuntimeError):
         runnable.with_retry(
             stop_after_attempt=2,
+            wait_exponential_jitter=False,
             retry_if_exception_type=(ValueError,),
         ).invoke(2)
 
@@ -2205,6 +2209,7 @@ def test_retrying(mocker: MockerFixture) -> None:
     with pytest.raises(ValueError):
         runnable.with_retry(
             stop_after_attempt=2,
+            wait_exponential_jitter=False,
             retry_if_exception_type=(ValueError,),
         ).batch([1, 2, 0])
 
@@ -2214,6 +2219,7 @@ def test_retrying(mocker: MockerFixture) -> None:
 
     output = runnable.with_retry(
         stop_after_attempt=2,
+        wait_exponential_jitter=False,
         retry_if_exception_type=(ValueError,),
     ).batch([1, 2, 0], return_exceptions=True)
 
@@ -2248,6 +2254,7 @@ async def test_async_retrying(mocker: MockerFixture) -> None:
     with pytest.raises(ValueError):
         await runnable.with_retry(
             stop_after_attempt=2,
+            wait_exponential_jitter=False,
             retry_if_exception_type=(ValueError, KeyError),
         ).ainvoke(1)
 
@@ -2257,6 +2264,7 @@ async def test_async_retrying(mocker: MockerFixture) -> None:
     with pytest.raises(RuntimeError):
         await runnable.with_retry(
             stop_after_attempt=2,
+            wait_exponential_jitter=False,
             retry_if_exception_type=(ValueError,),
         ).ainvoke(2)
 
@@ -2266,6 +2274,7 @@ async def test_async_retrying(mocker: MockerFixture) -> None:
     with pytest.raises(ValueError):
         await runnable.with_retry(
             stop_after_attempt=2,
+            wait_exponential_jitter=False,
             retry_if_exception_type=(ValueError,),
         ).abatch([1, 2, 0])
 
@@ -2275,6 +2284,7 @@ async def test_async_retrying(mocker: MockerFixture) -> None:
 
     output = await runnable.with_retry(
         stop_after_attempt=2,
+        wait_exponential_jitter=False,
         retry_if_exception_type=(ValueError,),
     ).abatch([1, 2, 0], return_exceptions=True)