AsyncCallbackHandler#

class langchain_core.callbacks.base.AsyncCallbackHandler[source]#

Async callback handler for LangChain.

Attributes

ignore_agent

Whether to ignore agent callbacks.

ignore_chain

Whether to ignore chain callbacks.

ignore_chat_model

Whether to ignore chat model callbacks.

ignore_custom_event

Ignore custom event.

ignore_llm

Whether to ignore LLM callbacks.

ignore_retriever

Whether to ignore retriever callbacks.

ignore_retry

Whether to ignore retry callbacks.

raise_error

Whether to raise an error if an exception occurs.

run_inline

Whether to run the callback inline.

Methods

on_agent_action(action, *, run_id[, ...])

Run on agent action.

on_agent_finish(finish, *, run_id[, ...])

Run on the agent end.

on_chain_end(outputs, *, run_id[, ...])

Run when a chain ends running.

on_chain_error(error, *, run_id[, ...])

Run when chain errors.

on_chain_start(serialized, inputs, *, run_id)

Run when a chain starts running.

on_chat_model_start(serialized, messages, *, ...)

Run when a chat model starts running.

on_custom_event(name, data, *, run_id[, ...])

Override to define a handler for a custom event.

on_llm_end(response, *, run_id[, ...])

Run when LLM ends running.

on_llm_error(error, *, run_id[, ...])

Run when LLM errors.

on_llm_new_token(token, *[, chunk, ...])

Run on new LLM token.

on_llm_start(serialized, prompts, *, run_id)

Run when LLM starts running.

on_retriever_end(documents, *, run_id[, ...])

Run on the retriever end.

on_retriever_error(error, *, run_id[, ...])

Run on retriever error.

on_retriever_start(serialized, query, *, run_id)

Run on the 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 an arbitrary text.

on_tool_end(output, *, run_id[, ...])

Run when the tool ends running.

on_tool_error(error, *, run_id[, ...])

Run when tool errors.

on_tool_start(serialized, input_str, *, run_id)

Run when the tool starts running.
async on_agent_action(action: AgentAction, *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, **kwargs: Any) → None[source]#

Run on agent action.

Parameters:

  • action (AgentAction) – The agent action.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

async on_agent_finish(finish: AgentFinish, *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, **kwargs: Any) → None[source]#

Run on the agent end.

Parameters:

  • finish (AgentFinish) – The agent finish.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

async on_chain_end(outputs: dict[str, Any], *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, **kwargs: Any) → None[source]#

Run when a chain ends running.

Parameters:

  • outputs (Dict[str, Any]) – The outputs of the chain.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

async on_chain_error(error: BaseException, *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, **kwargs: Any) → None[source]#

Run when chain errors.

Parameters:

  • error (BaseException) – The error that occurred.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

async on_chain_start(serialized: dict[str, Any], inputs: dict[str, Any], *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, metadata: dict[str, Any] | None = None, **kwargs: Any) → None[source]#

Run when a chain starts running.

Parameters:

  • serialized (Dict[str, Any]) – The serialized chain.

  • inputs (Dict[str, Any]) – The inputs.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • metadata (Optional[Dict[str, Any]]) – The metadata.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

async on_chat_model_start(serialized: dict[str, Any], messages: list[list[BaseMessage]], *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, metadata: dict[str, Any] | None = None, **kwargs: Any) → Any[source]#

Run when a chat model starts running.

ATTENTION: This method is called for chat models. If you’re implementing

a handler for a non-chat model, you should use on_llm_start instead.

Parameters:

  • serialized (Dict[str, Any]) – The serialized chat model.

  • messages (List[List[BaseMessage]]) – The messages.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • metadata (Optional[Dict[str, Any]]) – The metadata.

  • kwargs (Any) – Additional keyword arguments.

Return type:

Any

async on_custom_event(name: str, data: Any, *, run_id: UUID, tags: list[str] | None = None, metadata: dict[str, Any] | None = None, **kwargs: Any) → None[source]#

Override to define a handler for a custom event.

Parameters:

  • name (str) – The name of the custom event.

  • data (Any) – The data for the custom event. Format will match the format specified by the user.

  • run_id (UUID) – The ID of the run.

  • tags (list[str] | None) – The tags associated with the custom event (includes inherited tags).

  • metadata (dict[str, Any] | None) – The metadata associated with the custom event (includes inherited metadata).

  • kwargs (Any)

Return type:

None

Added in version 0.2.15.

async on_llm_end(response: LLMResult, *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, **kwargs: Any) → None[source]#

Run when LLM ends running.

Parameters:

  • response (LLMResult) – The response which was generated.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

async on_llm_error(error: BaseException, *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, **kwargs: Any) → None[source]#

Run when LLM errors.

Parameters:

  • error (BaseException) – The error that occurred.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID | None) – The parent run ID. This is the ID of the parent run.

  • tags (list[str] | None) – The tags.

  • kwargs (Any) –

    Additional keyword arguments. - response (LLMResult): The response which was generated before

    the error occurred.

Return type:

None

async on_llm_new_token(token: str, *, chunk: GenerationChunk | ChatGenerationChunk | None = None, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, **kwargs: Any) → None[source]#

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

Parameters:

  • token (str) – The new token.

  • chunk (GenerationChunk | ChatGenerationChunk) – The new generated chunk, containing content and other information.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

async on_llm_start(serialized: dict[str, Any], prompts: list[str], *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, metadata: dict[str, Any] | None = None, **kwargs: Any) → None[source]#

Run when LLM starts running.

ATTENTION: This method is called for non-chat models (regular LLMs). If

you’re implementing a handler for a chat model, you should use on_chat_model_start instead.

Parameters:

  • serialized (Dict[str, Any]) – The serialized LLM.

  • prompts (List[str]) – The prompts.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • metadata (Optional[Dict[str, Any]]) – The metadata.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

async on_retriever_end(documents: Sequence[Document], *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, **kwargs: Any) → None[source]#

Run on the retriever end.

Parameters:

  • documents (Sequence[Document]) – The documents retrieved.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

async on_retriever_error(error: BaseException, *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, **kwargs: Any) → None[source]#

Run on retriever error.

Parameters:

  • error (BaseException) – The error that occurred.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

async on_retriever_start(serialized: dict[str, Any], query: str, *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, metadata: dict[str, Any] | None = None, **kwargs: Any) → None[source]#

Run on the retriever start.

Parameters:

  • serialized (Dict[str, Any]) – The serialized retriever.

  • query (str) – The query.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • metadata (Optional[Dict[str, Any]]) – The metadata.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

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

Run on a retry event.

Parameters:

  • retry_state (RetryCallState) – The retry state.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • kwargs (Any) – Additional keyword arguments.

Return type:

Any

async on_text(text: str, *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, **kwargs: Any) → None[source]#

Run on an arbitrary text.

Parameters:

  • text (str) – The text.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

async on_tool_end(output: Any, *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, **kwargs: Any) → None[source]#

Run when the tool ends running.

Parameters:

  • output (Any) – The output of the tool.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

async on_tool_error(error: BaseException, *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, **kwargs: Any) → None[source]#

Run when tool errors.

Parameters:

  • error (BaseException) – The error that occurred.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

async on_tool_start(serialized: dict[str, Any], input_str: str, *, run_id: UUID, parent_run_id: UUID | None = None, tags: list[str] | None = None, metadata: dict[str, Any] | None = None, inputs: dict[str, Any] | None = None, **kwargs: Any) → None[source]#

Run when the tool starts running.

Parameters:

  • serialized (Dict[str, Any]) – The serialized tool.

  • input_str (str) – The input string.

  • run_id (UUID) – The run ID. This is the ID of the current run.

  • parent_run_id (UUID) – The parent run ID. This is the ID of the parent run.

  • tags (Optional[List[str]]) – The tags.

  • metadata (Optional[Dict[str, Any]]) – The metadata.

  • inputs (Optional[Dict[str, Any]]) – The inputs.

  • kwargs (Any) – Additional keyword arguments.

Return type:

None

Examples using AsyncCallbackHandler