Class BaseTracer`Abstract`

Abstract base class for creating callback handlers in the LangChain framework. It provides a set of optional methods that can be overridden in derived classes to handle various events during the execution of a LangChain application.

Hierarchy

BaseCallbackHandler
- BaseTracer

Index

Constructors

constructor

new BaseTracer(_fields?): BaseTracer
Parameters
- Optional _fields: BaseCallbackHandlerInput
Returns BaseTracer
Overrides BaseCallbackHandler.constructor
- Defined in langchain/src/callbacks/handlers/tracer.ts:50

Properties

awaitHandlers

awaitHandlers: boolean = ...

ignoreAgent

ignoreAgent: boolean = false

ignoreChain

ignoreChain: boolean = false

ignoreLLM

ignoreLLM: boolean = false

ignoreRetriever

ignoreRetriever: boolean = false

lc_kwargs

lc_kwargs: SerializedFields

lc_serializable

lc_serializable: boolean = false

`Abstract` name

name: string

`Protected` runMap

runMap: Map<string, Run> = ...

Accessors

lc_aliases

get lc_aliases(): undefined | {
[key: string]: string;
}
A map of aliases for constructor args. Keys are the attribute names, e.g. "foo". Values are the alias that will replace the key in serialization. This is used to eg. make argument names match Python.

Returns undefined | {
[key: string]: string;
}
Inherited from BaseCallbackHandler.lc_aliases
- Defined in langchain/src/callbacks/base.ts:297

lc_attributes

get lc_attributes(): undefined | {
[key: string]: string;
}
A map of additional attributes to merge with constructor args. Keys are the attribute names, e.g. "foo". Values are the attribute values, which will be serialized. These attributes need to be accepted by the constructor as arguments.

Returns undefined | {
[key: string]: string;
}
Inherited from BaseCallbackHandler.lc_attributes
- Defined in langchain/src/callbacks/base.ts:293

lc_id

get lc_id(): string[]
The final serialized identifier for the module.

Returns string[]
Inherited from BaseCallbackHandler.lc_id
- Defined in langchain/src/callbacks/base.ts:314

lc_namespace

get lc_namespace(): ["langchain", "callbacks", string]
A path to the module that contains the class, eg. ["langchain", "llms"] Usually should be the same as the entrypoint the class is exported from.

Returns ["langchain", "callbacks", string]
Inherited from BaseCallbackHandler.lc_namespace
- Defined in langchain/src/callbacks/base.ts:285

lc_secrets

get lc_secrets(): undefined | {
[key: string]: string;
}
A map of secrets, which will be omitted from serialization. Keys are paths to the secret in constructor args, e.g. "foo.bar.baz". Values are the secret ids, which will be used when deserializing.

Returns undefined | {
[key: string]: string;
}
Inherited from BaseCallbackHandler.lc_secrets
- Defined in langchain/src/callbacks/base.ts:289

Methods

copy

copy(): BaseTracer
Returns BaseTracer
Overrides BaseCallbackHandler.copy
- Defined in langchain/src/callbacks/handlers/tracer.ts:54

handleAgentAction

handleAgentAction(action, runId): Promise<void>
Called when an agent is about to execute an action, with the action and the run ID.
Parameters
- action: AgentAction
- runId: string
Returns Promise<void>
Overrides BaseCallbackHandler.handleAgentAction
- Defined in langchain/src/callbacks/handlers/tracer.ts:374

handleAgentEnd

handleAgentEnd(action, runId): Promise<void>
Called when an agent finishes execution, before it exits. with the final output and the run ID.
Parameters
- action: AgentFinish
- runId: string
Returns Promise<void>
Overrides BaseCallbackHandler.handleAgentEnd
- Defined in langchain/src/callbacks/handlers/tracer.ts:390

handleChainEnd

handleChainEnd(outputs, runId, _parentRunId?, _tags?, kwargs?): Promise<Run>
Called at the end of a Chain run, with the outputs and the run ID.
Parameters
- outputs: ChainValues
- runId: string
- Optional _parentRunId: string
- Optional _tags: string[]
- Optional kwargs: {
  inputs?: Record<string, unknown>;
  }
  - Optional inputs?: Record<string, unknown>
Returns Promise<Run>
Overrides BaseCallbackHandler.handleChainEnd
- Defined in langchain/src/callbacks/handlers/tracer.ts:255

handleChainError

handleChainError(error, runId, _parentRunId?, _tags?, kwargs?): Promise<Run>
Called if a Chain run encounters an error
Parameters
- error: Error
- runId: string
- Optional _parentRunId: string
- Optional _tags: string[]
- Optional kwargs: {
  inputs?: Record<string, unknown>;
  }
  - Optional inputs?: Record<string, unknown>
Returns Promise<Run>
Overrides BaseCallbackHandler.handleChainError
- Defined in langchain/src/callbacks/handlers/tracer.ts:280

handleChainStart

handleChainStart(chain, inputs, runId, parentRunId?, tags?, metadata?, runType?, name?): Promise<Run>
Called at the start of a Chain run, with the chain name and inputs and the run ID.
Parameters
- chain: Serialized
- inputs: ChainValues
- runId: string
- Optional parentRunId: string
- Optional tags: string[]
- Optional metadata: KVMap
- Optional runType: string
- Optional name: string
Returns Promise<Run>
Overrides BaseCallbackHandler.handleChainStart
- Defined in langchain/src/callbacks/handlers/tracer.ts:218

handleChatModelStart

handleChatModelStart(llm, messages, runId, parentRunId?, extraParams?, tags?, metadata?, name?): Promise<Run>
Called at the start of a Chat Model run, with the prompt(s) and the run ID.
Parameters
- llm: Serialized
- messages: BaseMessage[][]
- runId: string
- Optional parentRunId: string
- Optional extraParams: KVMap
- Optional tags: string[]
- Optional metadata: KVMap
- Optional name: string
Returns Promise<Run>
Overrides BaseCallbackHandler.handleChatModelStart
- Defined in langchain/src/callbacks/handlers/tracer.ts:145

handleLLMEnd

handleLLMEnd(output, runId): Promise<Run>
Called at the end of an LLM/ChatModel run, with the output and the run ID.
Parameters
- output: LLMResult
- runId: string
Returns Promise<Run>
Overrides BaseCallbackHandler.handleLLMEnd
- Defined in langchain/src/callbacks/handlers/tracer.ts:186

handleLLMError

handleLLMError(error, runId): Promise<Run>
Called if an LLM/ChatModel run encounters an error
Parameters
- error: Error
- runId: string
Returns Promise<Run>
Overrides BaseCallbackHandler.handleLLMError
- Defined in langchain/src/callbacks/handlers/tracer.ts:202

handleLLMNewToken

handleLLMNewToken(token, idx, runId, _parentRunId?, _tags?, fields?): Promise<Run>
Called when an LLM/ChatModel in streaming mode produces a new token
Parameters
- token: string
- idx: NewTokenIndices
  
  idx.prompt is the index of the prompt that produced the token (if there are multiple prompts) idx.completion is the index of the completion that produced the token (if multiple completions per prompt are requested)
- runId: string
- Optional _parentRunId: string
- Optional _tags: string[]
- Optional fields: HandleLLMNewTokenCallbackFields
Returns Promise<Run>
Overrides BaseCallbackHandler.handleLLMNewToken
- Defined in langchain/src/callbacks/handlers/tracer.ts:488

handleLLMStart

handleLLMStart(llm, prompts, runId, parentRunId?, extraParams?, tags?, metadata?, name?): Promise<Run>
Called at the start of an LLM or Chat Model run, with the prompt(s) and the run ID.
Parameters
- llm: Serialized
- prompts: string[]
- runId: string
- Optional parentRunId: string
- Optional extraParams: KVMap
- Optional tags: string[]
- Optional metadata: KVMap
- Optional name: string
Returns Promise<Run>
Overrides BaseCallbackHandler.handleLLMStart
- Defined in langchain/src/callbacks/handlers/tracer.ts:104

handleRetrieverEnd

handleRetrieverEnd(documents, runId): Promise<Run>
Parameters
- documents: Document<Record<string, unknown>>[]
- runId: string
Returns Promise<Run>
Overrides BaseCallbackHandler.handleRetrieverEnd
- Defined in langchain/src/callbacks/handlers/tracer.ts:440

handleRetrieverError

handleRetrieverError(error, runId): Promise<Run>
Parameters
- error: Error
- runId: string
Returns Promise<Run>
Overrides BaseCallbackHandler.handleRetrieverError
- Defined in langchain/src/callbacks/handlers/tracer.ts:459

handleRetrieverStart

handleRetrieverStart(retriever, query, runId, parentRunId?, tags?, metadata?, name?): Promise<Run>
Parameters
- retriever: Serialized
- query: string
- runId: string
- Optional parentRunId: string
- Optional tags: string[]
- Optional metadata: KVMap
- Optional name: string
Returns Promise<Run>
Overrides BaseCallbackHandler.handleRetrieverStart
- Defined in langchain/src/callbacks/handlers/tracer.ts:403

handleText

handleText(text, runId): Promise<void>
Parameters
- text: string
- runId: string
Returns Promise<void>
Overrides BaseCallbackHandler.handleText
- Defined in langchain/src/callbacks/handlers/tracer.ts:475

handleToolEnd

handleToolEnd(output, runId): Promise<Run>
Called at the end of a Tool run, with the tool output and the run ID.
Parameters
- output: string
- runId: string
Returns Promise<Run>
Overrides BaseCallbackHandler.handleToolEnd
- Defined in langchain/src/callbacks/handlers/tracer.ts:342

handleToolError

handleToolError(error, runId): Promise<Run>
Called if a Tool run encounters an error
Parameters
- error: Error
- runId: string
Returns Promise<Run>
Overrides BaseCallbackHandler.handleToolError
- Defined in langchain/src/callbacks/handlers/tracer.ts:358

handleToolStart

handleToolStart(tool, input, runId, parentRunId?, tags?, metadata?, name?): Promise<Run>
Called at the start of a Tool run, with the tool name and input and the run ID.
Parameters
- tool: Serialized
- input: string
- runId: string
- Optional parentRunId: string
- Optional tags: string[]
- Optional metadata: KVMap
- Optional name: string
Returns Promise<Run>
Overrides BaseCallbackHandler.handleToolStart
- Defined in langchain/src/callbacks/handlers/tracer.ts:305

toJSON

toJSON(): Serialized
Returns Serialized
Inherited from BaseCallbackHandler.toJSON
- Defined in langchain/src/callbacks/base.ts:356

toJSONNotImplemented

toJSONNotImplemented(): SerializedNotImplemented
Returns SerializedNotImplemented
Inherited from BaseCallbackHandler.toJSONNotImplemented
- Defined in langchain/src/callbacks/base.ts:360

`Optional` onAgentAction

onAgentAction(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:535

`Optional` onAgentEnd

onAgentEnd(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:537

`Optional` onChainEnd

onChainEnd(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:525

`Optional` onChainError

onChainError(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:527

`Optional` onChainStart

onChainStart(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:523

`Optional` onLLMEnd

onLLMEnd(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:519

`Optional` onLLMError

onLLMError(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:521

`Optional` onLLMNewToken

onLLMNewToken(run, token): void | Promise<void>
Parameters
- run: Run
- token: string
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:547

`Optional` onLLMStart

onLLMStart(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:517

`Optional` onRetrieverEnd

onRetrieverEnd(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:541

`Optional` onRetrieverError

onRetrieverError(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:543

`Optional` onRetrieverStart

onRetrieverStart(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:539

`Optional` onRunCreate

onRunCreate(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:513

`Optional` onRunUpdate

onRunUpdate(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:515

`Optional` onText

onText(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:545

`Optional` onToolEnd

onToolEnd(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:531

`Optional` onToolError

onToolError(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:533

`Optional` onToolStart

onToolStart(run): void | Promise<void>
Parameters
- run: Run
Returns void | Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:529

`Static` fromMethods

fromMethods(methods): Handler
Parameters
- methods: BaseCallbackHandlerMethodsClass
Returns Handler
Inherited from BaseCallbackHandler.fromMethods
- Defined in langchain/src/callbacks/base.ts:364

`Static` lc_name

lc_name(): string
The name of the serializable. Override to provide an alias or to preserve the serialized module name in minified environments.

Implemented as a static method to support loading logic.

Returns string
Inherited from BaseCallbackHandler.lc_name
- Defined in langchain/src/callbacks/base.ts:307

`Protected` _addChildRun

_addChildRun(parentRun, childRun): void
Parameters
- parentRun: Run
- childRun: Run
Returns void
- Defined in langchain/src/callbacks/handlers/tracer.ts:60

`Protected` _endTrace

_endTrace(run): Promise<void>
Parameters
- run: Run
Returns Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:79

`Protected` _getExecutionOrder

_getExecutionOrder(parentRunId): number
Parameters
- parentRunId: undefined | string
Returns number
- Defined in langchain/src/callbacks/handlers/tracer.ts:94

`Protected` _startTrace

_startTrace(run): Promise<void>
Parameters
- run: Run
Returns Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:64

`Protected` `Abstract` persistRun

persistRun(run): Promise<void>
Parameters
- run: Run
Returns Promise<void>
- Defined in langchain/src/callbacks/handlers/tracer.ts:58

Class BaseTracerAbstract

Hierarchy

Index

Constructors

Properties

Accessors

Methods

Constructors

constructor

Parameters

Optional _fields: BaseCallbackHandlerInput

Returns BaseTracer

Properties

awaitHandlers

ignoreAgent

ignoreChain

ignoreLLM

ignoreRetriever

lc_kwargs

lc_serializable

Abstract name

Protected runMap

Accessors

lc_aliases

Returns undefined | { [key: string]: string; }

lc_attributes

Returns undefined | { [key: string]: string; }

lc_id

Returns string[]

lc_namespace

Returns ["langchain", "callbacks", string]

lc_secrets

Returns undefined | { [key: string]: string; }

Methods

copy

Returns BaseTracer

handleAgentAction

Parameters

action: AgentAction

runId: string

Returns Promise<void>

handleAgentEnd

Parameters

action: AgentFinish

runId: string

Returns Promise<void>

handleChainEnd

Parameters

outputs: ChainValues

runId: string

Optional _parentRunId: string

Optional _tags: string[]

Optional kwargs: { inputs?: Record<string, unknown>; }

Optional inputs?: Record<string, unknown>

Returns Promise<Run>

handleChainError

Parameters

error: Error

runId: string

Optional _parentRunId: string

Optional _tags: string[]

Optional kwargs: { inputs?: Record<string, unknown>; }

Optional inputs?: Record<string, unknown>

Returns Promise<Run>

handleChainStart

Parameters

chain: Serialized

inputs: ChainValues

runId: string

Optional parentRunId: string

Optional tags: string[]

Optional metadata: KVMap

Optional runType: string

Optional name: string

Returns Promise<Run>

handleChatModelStart

Parameters

llm: Serialized

messages: BaseMessage[][]

runId: string

Class BaseTracer`Abstract`

`Optional` _fields: BaseCallbackHandlerInput

`Abstract` name

`Protected` runMap

Returns undefined | {
[key: string]: string;
}

Returns undefined | {
[key: string]: string;
}

Returns undefined | {
[key: string]: string;
}

`Optional` _parentRunId: string

`Optional` _tags: string[]

`Optional` kwargs: {
inputs?: Record<string, unknown>;
}

`Optional` inputs?: Record<string, unknown>

`Optional` _parentRunId: string

`Optional` _tags: string[]

`Optional` kwargs: {
inputs?: Record<string, unknown>;
}

`Optional` inputs?: Record<string, unknown>

`Optional` parentRunId: string

`Optional` tags: string[]

`Optional` metadata: KVMap

`Optional` runType: string

`Optional` name: string

`Optional` parentRunId: string

`Optional` extraParams: KVMap

`Optional` tags: string[]

`Optional` metadata: KVMap

`Optional` name: string

`Optional` _parentRunId: string

`Optional` _tags: string[]

`Optional` fields: HandleLLMNewTokenCallbackFields

`Optional` parentRunId: string

`Optional` extraParams: KVMap

`Optional` tags: string[]

`Optional` metadata: KVMap

`Optional` name: string

`Optional` parentRunId: string

`Optional` tags: string[]

`Optional` metadata: KVMap

`Optional` name: string