LogStreamCallbackHandler#

class langchain_core.tracers.log_stream.LogStreamCallbackHandler(*, auto_close: bool = True, include_names: Sequence[str] | None = None, include_types: Sequence[str] | None = None, include_tags: Sequence[str] | None = None, exclude_names: Sequence[str] | None = None, exclude_types: Sequence[str] | None = None, exclude_tags: Sequence[str] | None = None, _schema_format: Literal['original', 'streaming_events'] = 'streaming_events')[source]#

Tracer that streams run logs to a stream.

A tracer that streams run logs to a stream.

Parameters:

auto_close (bool) – Whether to close the stream when the root run finishes.
include_names (Optional[Sequence[str]]) – Only include runs from Runnables with matching names.
include_types (Optional[Sequence[str]]) – Only include runs from Runnables with matching types.
include_tags (Optional[Sequence[str]]) – Only include runs from Runnables with matching tags.
exclude_names (Optional[Sequence[str]]) – Exclude runs from Runnables with matching names.
exclude_types (Optional[Sequence[str]]) – Exclude runs from Runnables with matching types.
exclude_tags (Optional[Sequence[str]]) – Exclude runs from Runnables with matching tags.
_schema_format (Literal['original', 'streaming_events']) –
Primarily changes how the inputs and outputs are handled. For internal use only. This API will change. - ‘original’ is the format used by all current tracers.

This format is slightly inconsistent with respect to inputs and outputs.
- ’streaming_events’ is used for supporting streaming events, for internal usage. It will likely change in the future, or be deprecated entirely in favor of a dedicated async tracer for streaming events.

Raises:

ValueError – If an invalid schema format is provided (internal use only).

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`
`raise_error`	Whether to raise an error if an exception occurs.
`run_inline`	Whether to run the callback inline.

Methods

`__init__`(*[, auto_close, include_names, ...])	A tracer that streams run logs to a stream.
`include_run`(run)	Check if a Run should be included in the log.
`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.
`send`(*ops)	Send a patch to the stream, return False if the stream is closed.
`tap_output_aiter`(run_id, output)	Tap an output async iterator to stream its values to the log.
`tap_output_iter`(run_id, output)	Tap an output async iterator to stream its values to the log.

__init__(*, auto_close: bool = True, include_names: Sequence[str] | None = None, include_types: Sequence[str] | None = None, include_tags: Sequence[str] | None = None, exclude_names: Sequence[str] | None = None, exclude_types: Sequence[str] | None = None, exclude_tags: Sequence[str] | None = None, _schema_format: Literal['original', 'streaming_events'] = 'streaming_events') → None[source]#

A tracer that streams run logs to a stream.

Parameters:

auto_close (bool) – Whether to close the stream when the root run finishes.
include_names (Sequence[str] | None) – Only include runs from Runnables with matching names.
include_types (Sequence[str] | None) – Only include runs from Runnables with matching types.
include_tags (Sequence[str] | None) – Only include runs from Runnables with matching tags.
exclude_names (Sequence[str] | None) – Exclude runs from Runnables with matching names.
exclude_types (Sequence[str] | None) – Exclude runs from Runnables with matching types.
exclude_tags (Sequence[str] | None) – Exclude runs from Runnables with matching tags.
_schema_format (Literal['original', 'streaming_events']) –
Primarily changes how the inputs and outputs are handled. For internal use only. This API will change. - ‘original’ is the format used by all current tracers.

This format is slightly inconsistent with respect to inputs and outputs.
- ’streaming_events’ is used for supporting streaming events, for internal usage. It will likely change in the future, or be deprecated entirely in favor of a dedicated async tracer for streaming events.

Raises:

ValueError – If an invalid schema format is provided (internal use only).

Return type:

None

include_run(run: Run) → bool[source]#

Check if a Run should be included in the log.

Parameters:: run (Run) – The Run to check.
Returns:: True if the run should be included, False otherwise.
Return type:: bool

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 (Dict[str, Any] | None) – 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 (Dict[str, Any] | None) – 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 (List[str] | None) – The tags for the run. Defaults to None.
parent_run_id (UUID | None) – The parent run ID. Defaults to None.
metadata (Dict[str, Any] | None) – The metadata for the run. Defaults to None.
run_type (str | None) – The type of the run. Defaults to None.
name (str | None) – 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 (List[str] | None) – The tags for the run. Defaults to None.
parent_run_id (UUID | None) – The parent run ID. Defaults to None.
metadata (Dict[str, Any] | None) – The metadata for the run. Defaults to None.
name (str | None) – 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 (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:

Any

New 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 (GenerationChunk | ChatGenerationChunk | None) – The chunk. Defaults to None.
run_id (UUID) – The run ID.
parent_run_id (UUID | None) – 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 (List[str] | None) – The tags for the run. Defaults to None.
parent_run_id (UUID | None) – The parent run ID. Defaults to None.
metadata (Dict[str, Any] | None) – The metadata for the run. Defaults to None.
name (str | None) – 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 (UUID | None) – The parent run ID. Defaults to None.
tags (List[str] | None) – The tags for the run. Defaults to None.
metadata (Dict[str, Any] | None) – The metadata for the run. Defaults to None.
name (str | None) – 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 (List[str] | None) – The tags for the run. Defaults to None.
parent_run_id (UUID | None) – The parent run ID. Defaults to None.
metadata (Dict[str, Any] | None) – The metadata for the run. Defaults to None.
name (str | None) – The name of the run.
inputs (Dict[str, Any] | None) – The inputs for the tool.
kwargs (Any) – Additional arguments.

Returns:

The run.

Return type:

Run

send(*ops: Dict[str, Any]) → bool[source]#

Send a patch to the stream, return False if the stream is closed.

Parameters:

*ops (Dict[str, Any]) – The operations to send to the stream.

Returns:

True if the patch was sent successfully, False if the stream: is closed.

Return type:

bool

async tap_output_aiter(run_id: UUID, output: AsyncIterator[T]) → AsyncIterator[T][source]#

Tap an output async iterator to stream its values to the log.

Parameters:

run_id (UUID) – The ID of the run.
output (AsyncIterator[T]) – The output async iterator.

Yields:

T – The output value.

Return type:

AsyncIterator[T]

tap_output_iter(run_id: UUID, output: Iterator[T]) → Iterator[T][source]#

Tap an output async iterator to stream its values to the log.

Parameters:

run_id (UUID) – The ID of the run.
output (Iterator[T]) – The output iterator.

Yields:

T – The output value.

Return type:

Iterator[T]