Add RunnableRetry Documentation (#13074)

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

@@ -644,6 +644,17 @@ class Runnable(Generic[Input, Output], ABC):
         wait_exponential_jitter: bool = True,
         stop_after_attempt: int = 3,
     ) -> Runnable[Input, Output]:
+        """Create a new Runnable that retries the original runnable on exceptions.
+
+        Args:
+            retry_if_exception_type: A tuple of exception types to retry on
+            wait_exponential_jitter: Whether to add jitter to the wait time
+                                     between retries
+            stop_after_attempt: The maximum number of attempts to make before giving up
+
+        Returns:
+            A new Runnable that retries the original runnable on exceptions.
+        """
         from langchain.schema.runnable.retry import RunnableRetry
 
         return RunnableRetry(

libs/langchain/langchain/schema/runnable/retry.py

@@ -35,13 +35,84 @@ U = TypeVar("U")
 
 
 class RunnableRetry(RunnableBinding[Input, Output]):
-    """Retry a Runnable if it fails."""
+    """Retry a Runnable if it fails.
+
+    A RunnableRetry helps can be used to add retry logic to any object
+    that subclasses the base Runnable.
+
+    Such retries are especially useful for network calls that may fail
+    due to transient errors.
+
+    The RunnableRetry is implemented as a RunnableBinding. The easiest
+    way to use it is through the `.with_retry()` method on all Runnables.
+
+    Example:
+
+    Here's an example that uses a RunnableLambda to raise an exception
+
+        .. code-block:: python
+
+            import time
+
+            def foo(input) -> None:
+                '''Fake function that raises an exception.'''
+                raise ValueError("Invoking foo failed. At time {time.time()}")
+
+            runnable = RunnableLambda(foo)
+
+            runnable_with_retries = runnable.with_retry(
+                retry_exception_types=(ValueError,), # Retry only on ValueError
+                wait_exponential_jitter=True, # Add jitter to the exponential backoff
+                max_attempt_number=2, # Try twice
+            )
+
+            # The method invocation above is equivalent to the longer form below:
+
+            runnable_with_retries = RunnableRetry(
+                bound=runnable,
+                retry_exception_types=(ValueError,),
+                max_attempt_number=2,
+                wait_exponential_jitter=True
+            )
+
+    This logic can be used to retry any Runnable, including a chain of Runnables,
+    but in general it's best practice to keep the scope of the retry as small as
+    possible. For example, if you have a chain of Runnables, you should only retry
+    the Runnable that is likely to fail, not the entire chain.
+
+    Example:
+
+        .. code-block:: python
+
+            from langchain.chat_models import ChatOpenAI
+            from langchain.prompts import PromptTemplate
+
+            template = PromptTemplate.from_template("tell me a joke about {topic}.")
+            model = ChatOpenAI(temperature=0.5)
+
+            # Good
+            chain = template | model.with_retry()
+
+            # Bad
+            chain = template | model
+            retryable_chain = chain.with_retry()
+    """
 
     retry_exception_types: Tuple[Type[BaseException], ...] = (Exception,)
+    """The exception types to retry on. By default all exceptions are retried.
+    
+    In general you should only retry on exceptions that are likely to be
+    transient, such as network errors.
+    
+    Good exceptions to retry are all server errors (5xx) and selected client
+    errors (4xx) such as 429 Too Many Requests.
+    """
 
     wait_exponential_jitter: bool = True
+    """Whether to add jitter to the exponential backoff."""
 
     max_attempt_number: int = 3
+    """The maximum number of attempts to retry the runnable."""
 
     @property
     def _kwargs_retrying(self) -> Dict[str, Any]: