FunctionCallbackHandler#

class langchain_core.tracers.stdout.FunctionCallbackHandler(
function: Callable[[str], None],
**kwargs: Any,
)[source]#

Tracer that calls a function with a single str parameter.

Create a FunctionCallbackHandler.

Parameters:
  • function (Callable[[str], None]) – The callback function to call.

  • kwargs (Any)

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.

log_missing_parent

name

The name of the tracer.

raise_error

Whether to raise an error if an exception occurs.

run_inline

Whether to run the callback inline.

Methods

__init__(function, **kwargs)

Create a FunctionCallbackHandler.

get_breadcrumbs(run)

Get the breadcrumbs of a run.

get_parents(run)

Get the parents of a run.

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[, inputs])

End a trace for a chain run.

on_chain_error(error, *[, inputs])

Handle an error for a chain run.

on_chain_start(serialized, inputs, *, run_id)

Start a trace for a chain run.

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

Start a trace for an LLM run.

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

Override to define a handler for a custom event.

on_llm_end(response, *, run_id, **kwargs)

End a trace for an LLM run.

on_llm_error(error, *, run_id, **kwargs)

Handle an error for an LLM run.

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

Run on new LLM token.

on_llm_start(serialized, prompts, *, run_id)

Start a trace for an LLM run.

on_retriever_end(documents, *, run_id, **kwargs)

Run when the Retriever ends running.

on_retriever_error(error, *, run_id, **kwargs)

Run when Retriever errors.

on_retriever_start(serialized, query, *, run_id)

Run when the Retriever starts running.

on_retry(retry_state, *, run_id, **kwargs)

Run on retry.

on_text(text, *, run_id[, parent_run_id])

Run on an arbitrary text.

on_tool_end(output, *, run_id, **kwargs)

End a trace for a tool run.

on_tool_error(error, *, run_id, **kwargs)

Handle an error for a tool run.

on_tool_start(serialized, input_str, *, run_id)

Start a trace for a tool run.

__init__(
function: Callable[[str], None],
**kwargs: Any,
) None[source]#

Create a FunctionCallbackHandler.

Parameters:
  • function (Callable[[str], None]) – The callback function to call.

  • kwargs (Any)

Return type:

None

get_breadcrumbs(
run: RunTree,
) str[source]#

Get the breadcrumbs of a run.

Parameters:

run (RunTree) – The run to get the breadcrumbs of.

Returns:

A string with the breadcrumbs of the run.

Return type:

str

get_parents(
run: RunTree,
) list[RunTree][source]#

Get the parents of a run.

Parameters:

run (RunTree) – The run to get the parents of.

Returns:

A list of parent runs.

Return type:

list[RunTree]

on_agent_action(
action: AgentAction,
*,
run_id: UUID,
parent_run_id: UUID | None = None,
**kwargs: Any,
) Any#

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.

  • kwargs (Any) – Additional keyword arguments.

Return type:

Any

on_agent_finish(
finish: AgentFinish,
*,
run_id: UUID,
parent_run_id: UUID | None = None,
**kwargs: Any,
) Any#

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.

  • kwargs (Any) – Additional keyword arguments.

Return type:

Any

on_chain_end(
outputs: dict[str, Any],
*,
run_id: UUID,
inputs: dict[str, Any] | None = None,
**kwargs: Any,
) Run#

End a trace for a chain run.

Parameters:
  • outputs (dict[str, Any]) – The outputs for the chain.

  • run_id (UUID) – The run ID.

  • inputs (Optional[dict[str, Any]]) – The inputs for the chain. Defaults to None.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

on_chain_error(
error: BaseException,
*,
inputs: dict[str, Any] | None = None,
run_id: UUID,
**kwargs: Any,
) Run#

Handle an error for a chain run.

Parameters:
  • error (BaseException) – The error.

  • inputs (Optional[dict[str, Any]]) – The inputs for the chain. Defaults to None.

  • run_id (UUID) – The run ID.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

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

Start a trace for a chain run.

Parameters:
  • serialized (dict[str, Any]) – The serialized chain.

  • inputs (dict[str, Any]) – The inputs for the chain.

  • run_id (UUID) – The run ID.

  • tags (Optional[list[str]]) – The tags for the run. Defaults to None.

  • parent_run_id (Optional[UUID]) – The parent run ID. Defaults to None.

  • metadata (Optional[dict[str, Any]]) – The metadata for the run. Defaults to None.

  • run_type (Optional[str]) – The type of the run. Defaults to None.

  • name (Optional[str]) – The name of the run.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

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

Start a trace for an LLM run.

Parameters:
  • serialized (dict[str, Any]) – The serialized model.

  • messages (list[list[BaseMessage]]) – The messages to start the chat with.

  • run_id (UUID) – The run ID.

  • tags (Optional[list[str]]) – The tags for the run. Defaults to None.

  • parent_run_id (Optional[UUID]) – The parent run ID. Defaults to None.

  • metadata (Optional[dict[str, Any]]) – The metadata for the run. Defaults to None.

  • name (Optional[str]) – The name of the run.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

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

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 (Optional[list[str]]) – The tags associated with the custom event (includes inherited tags).

  • metadata (Optional[dict[str, Any]]) – The metadata associated with the custom event (includes inherited metadata).

  • kwargs (Any)

Return type:

Any

Added in version 0.2.15.

on_llm_end(
response: LLMResult,
*,
run_id: UUID,
**kwargs: Any,
) Run#

End a trace for an LLM run.

Parameters:
  • response (LLMResult) – The response.

  • run_id (UUID) – The run ID.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

on_llm_error(
error: BaseException,
*,
run_id: UUID,
**kwargs: Any,
) Run#

Handle an error for an LLM run.

Parameters:
  • error (BaseException) – The error.

  • run_id (UUID) – The run ID.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

on_llm_new_token(
token: str,
*,
chunk: GenerationChunk | ChatGenerationChunk | None = None,
run_id: UUID,
parent_run_id: UUID | None = None,
**kwargs: Any,
) Run#

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

Parameters:
  • token (str) – The token.

  • chunk (Optional[Union[GenerationChunk, ChatGenerationChunk]]) – The chunk. Defaults to None.

  • run_id (UUID) – The run ID.

  • parent_run_id (Optional[UUID]) – The parent run ID. Defaults to None.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

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

Start a trace for an LLM run.

Parameters:
  • serialized (dict[str, Any]) – The serialized model.

  • prompts (list[str]) – The prompts to start the LLM with.

  • run_id (UUID) – The run ID.

  • tags (Optional[list[str]]) – The tags for the run. Defaults to None.

  • parent_run_id (Optional[UUID]) – The parent run ID. Defaults to None.

  • metadata (Optional[dict[str, Any]]) – The metadata for the run. Defaults to None.

  • name (Optional[str]) – The name of the run.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

on_retriever_end(
documents: Sequence[Document],
*,
run_id: UUID,
**kwargs: Any,
) Run#

Run when the Retriever ends running.

Parameters:
  • documents (Sequence[Document]) – The documents.

  • run_id (UUID) – The run ID.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

on_retriever_error(
error: BaseException,
*,
run_id: UUID,
**kwargs: Any,
) Run#

Run when Retriever errors.

Parameters:
  • error (BaseException) – The error.

  • run_id (UUID) – The run ID.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

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,
name: str | None = None,
**kwargs: Any,
) Run#

Run when the Retriever starts running.

Parameters:
  • serialized (dict[str, Any]) – The serialized retriever.

  • query (str) – The query.

  • run_id (UUID) – The run ID.

  • parent_run_id (Optional[UUID]) – The parent run ID. Defaults to None.

  • tags (Optional[list[str]]) – The tags for the run. Defaults to None.

  • metadata (Optional[dict[str, Any]]) – The metadata for the run. Defaults to None.

  • name (Optional[str]) – The name of the run.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

on_retry(
retry_state: RetryCallState,
*,
run_id: UUID,
**kwargs: Any,
) Run#

Run on retry.

Parameters:
  • retry_state (RetryCallState) – The retry state.

  • run_id (UUID) – The run ID.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

on_text(
text: str,
*,
run_id: UUID,
parent_run_id: UUID | None = None,
**kwargs: Any,
) Any#

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.

  • kwargs (Any) – Additional keyword arguments.

Return type:

Any

on_tool_end(
output: Any,
*,
run_id: UUID,
**kwargs: Any,
) Run#

End a trace for a tool run.

Parameters:
  • output (Any) – The output for the tool.

  • run_id (UUID) – The run ID.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

on_tool_error(
error: BaseException,
*,
run_id: UUID,
**kwargs: Any,
) Run#

Handle an error for a tool run.

Parameters:
  • error (BaseException) – The error.

  • run_id (UUID) – The run ID.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

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

Start a trace for a tool run.

Parameters:
  • serialized (dict[str, Any]) – The serialized tool.

  • input_str (str) – The input string.

  • run_id (UUID) – The run ID.

  • tags (Optional[list[str]]) – The tags for the run. Defaults to None.

  • parent_run_id (Optional[UUID]) – The parent run ID. Defaults to None.

  • metadata (Optional[dict[str, Any]]) – The metadata for the run. Defaults to None.

  • name (Optional[str]) – The name of the run.

  • inputs (Optional[dict[str, Any]]) – The inputs for the tool.

  • kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run