langchain.callbacks.streaming_aiter_final_only.AsyncFinalIteratorCallbackHandler

class langchain.callbacks.streaming_aiter_final_only.AsyncFinalIteratorCallbackHandler(*, answer_prefix_tokens: Optional[List[str]] = None, strip_tokens: bool = True, stream_prefix: bool = False)

Callback handler that returns an async iterator. Only the final output of the agent will be iterated.

Instantiate AsyncFinalIteratorCallbackHandler.

Parameters

• answer_prefix_tokens – Token sequence that prefixes the answer. Default is [“Final”, “Answer”, “:”]

• strip_tokens – Ignore white spaces and new lines when comparing answer_prefix_tokens to last tokens? (to determine if answer has been reached)

• stream_prefix – Should answer prefix itself also be streamed?

Attributes

always_verbose
ignore_agent	Whether to ignore agent callbacks.
ignore_chain	Whether to ignore chain callbacks.
ignore_chat_model	Whether to ignore chat model callbacks.
ignore_llm	Whether to ignore LLM callbacks.
ignore_retriever	Whether to ignore retriever callbacks.
ignore_retry	Whether to ignore retry callbacks.
raise_error
run_inline

Methods

__init__(*[, answer_prefix_tokens, ...])	Instantiate AsyncFinalIteratorCallbackHandler.
aiter()
append_to_last_tokens(token)
check_if_answer_reached()
on_agent_action(action, *, run_id[, ...])	Run on agent action.
on_agent_finish(finish, *, run_id[, ...])	Run on agent end.
on_chain_end(outputs, *, run_id[, ...])	Run when chain ends running.
on_chain_error(error, *, run_id[, ...])	Run when chain errors.
on_chain_start(serialized, inputs, *, run_id)	Run when chain starts running.
on_chat_model_start(serialized, messages, *, ...)	Run when a chat model starts running.
on_llm_end(response, **kwargs)	Run when LLM ends running.
on_llm_error(error, **kwargs)	Run when LLM errors. :param error: The error that occurred. :type error: BaseException :param kwargs: Additional keyword arguments. - response (LLMResult): The response which was generated before the error occurred. :type kwargs: Any.
on_llm_new_token(token, **kwargs)	Run on new LLM token.
on_llm_start(serialized, prompts, **kwargs)	Run when LLM starts running.
on_retriever_end(documents, *, run_id[, ...])	Run on retriever end.
on_retriever_error(error, *, run_id[, ...])	Run on retriever error.
on_retriever_start(serialized, query, *, run_id)	Run on retriever start.
on_retry(retry_state, *, run_id[, parent_run_id])	Run on a retry event.
on_text(text, *, run_id[, parent_run_id, tags])	Run on arbitrary text.
on_tool_end(output, *, run_id[, ...])	Run when tool ends running.
on_tool_error(error, *, run_id[, ...])	Run when tool errors.
on_tool_start(serialized, input_str, *, run_id)	Run when tool starts running.

__init__(*, answer_prefix_tokens: Optional[List[str]] = None, strip_tokens: bool = True, stream_prefix: bool = False) → None

Instantiate AsyncFinalIteratorCallbackHandler.

Parameters

• answer_prefix_tokens – Token sequence that prefixes the answer. Default is [“Final”, “Answer”, “:”]

• strip_tokens – Ignore white spaces and new lines when comparing answer_prefix_tokens to last tokens? (to determine if answer has been reached)

• stream_prefix – Should answer prefix itself also be streamed?

async aiter() → AsyncIterator[str]

append_to_last_tokens(token: str) → None

check_if_answer_reached() → bool

async on_agent_action(action: AgentAction, *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, **kwargs: Any) → None

Run on agent action.

async on_agent_finish(finish: AgentFinish, *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, **kwargs: Any) → None

Run on agent end.

async on_chain_end(outputs: Dict[str, Any], *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, **kwargs: Any) → None

Run when chain ends running.

async on_chain_error(error: BaseException, *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, **kwargs: Any) → None

Run when chain errors.

async on_chain_start(serialized: Dict[str, Any], inputs: Dict[str, Any], *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, metadata: Optional[Dict[str, Any]] = None, **kwargs: Any) → None

Run when chain starts running.

async on_chat_model_start(serialized: Dict[str, Any], messages: List[List[BaseMessage]], *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, metadata: Optional[Dict[str, Any]] = None, **kwargs: Any) → Any

Run when a chat model starts running.

async on_llm_end(response: LLMResult, **kwargs: Any) → None

Run when LLM ends running.

async on_llm_error(error: BaseException, **kwargs: Any) → None

Run when LLM errors. :param error: The error that occurred. :type error: BaseException :param kwargs: Additional keyword arguments.

• response (LLMResult): The response which was generated before

  the error occurred.

async on_llm_new_token(token: str, **kwargs: Any) → None

Run on new LLM token. Only available when streaming is enabled.

async on_llm_start(serialized: Dict[str, Any], prompts: List[str], **kwargs: Any) → None

Run when LLM starts running.

async on_retriever_end(documents: Sequence[Document], *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, **kwargs: Any) → None

Run on retriever end.

async on_retriever_error(error: BaseException, *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, **kwargs: Any) → None

Run on retriever error.

async on_retriever_start(serialized: Dict[str, Any], query: str, *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, metadata: Optional[Dict[str, Any]] = None, **kwargs: Any) → None

Run on retriever start.

async on_retry(retry_state: RetryCallState, *, run_id: UUID, parent_run_id: Optional[UUID] = None, **kwargs: Any) → Any

Run on a retry event.

async on_text(text: str, *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, **kwargs: Any) → None

Run on arbitrary text.

async on_tool_end(output: str, *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, **kwargs: Any) → None

Run when tool ends running.

async on_tool_error(error: BaseException, *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, **kwargs: Any) → None

Run when tool errors.

async on_tool_start(serialized: Dict[str, Any], input_str: str, *, run_id: UUID, parent_run_id: Optional[UUID] = None, tags: Optional[List[str]] = None, metadata: Optional[Dict[str, Any]] = None, inputs: Optional[Dict[str, Any]] = None, **kwargs: Any) → None

Run when tool starts running.