langchain.chains.sequential.SequentialChain

Note

SequentialChain implements the standard Runnable Interface. 🏃

The Runnable Interface has additional methods that are available on runnables, such as with_types, with_retry, assign, bind, get_graph, and more.

class langchain.chains.sequential.SequentialChain

Bases: Chain

Chain where the outputs of one chain feed directly into next.

param callback_manager: Optional[BaseCallbackManager] = None

[DEPRECATED] Use callbacks instead.

param callbacks: Callbacks = None

Optional list of callback handlers (or callback manager). Defaults to None. Callback handlers are called throughout the lifecycle of a call to a chain, starting with on_chain_start, ending with on_chain_end or on_chain_error. Each custom chain can optionally call additional callback methods, see Callback docs for full details.

param chains: List[Chain] [Required]

param input_variables: List]str] [Required]

param memory: Optional[BaseMemory] = None

Optional memory object. Defaults to None. Memory is a class that gets called at the start and at the end of every chain. At the start, memory loads variables and passes them along in the chain. At the end, it saves any returned variables. There are many different types of memory - please see memory docs for the full catalog.

param metadata: Optional[Dict[str, Any]] = None

Optional metadata associated with the chain. Defaults to None. This metadata will be associated with each call to this chain, and passed as arguments to the handlers defined in callbacks. You can use these to eg identify a specific instance of a chain with its use case.

param return_all: bool = False

param tags: Optional[List]str] = None

Optional list of tags associated with the chain. Defaults to None. These tags will be associated with each call to this chain, and passed as arguments to the handlers defined in callbacks. You can use these to eg identify a specific instance of a chain with its use case.

param verbose: bool [Optional]

Whether or not run in verbose mode. In verbose mode, some intermediate logs will be printed to the console. Defaults to the global verbose value, accessible via langchain.globals.get_verbose().

__call__(inputs: Union[Dict[str, Any], Any], return_only_outputs: bool = False, callbacks: Optional[Union[List[BaseCallbackHandler], BaseCallbackManager]] = None, *, tags: Optional[List]str] = None, metadata: Optional[Dict[str, Any]] = None, run_name: Optional[str] = None, include_run_info: bool = False) → Dict[str, Any]

Deprecated since version langchain==0.1.0: Use invoke instead.

Execute the chain.

Parameters

• inputs (Union[Dict[str, Any], Any]) – Dictionary of inputs, or single input if chain expects only one param. Should contain all inputs specified in Chain.input_keys except for inputs that will be set by the chain’s memory.

• return_only_outputs (bool) – Whether to return only outputs in the response. If True, only new keys generated by this chain will be returned. If False, both input keys and new keys generated by this chain will be returned. Defaults to False.

• callbacks (Optional[Union[List[BaseCallbackHandler], BaseCallbackManager]]) – Callbacks to use for this chain run. These will be called in addition to callbacks passed to the chain during construction, but only these runtime callbacks will propagate to calls to other objects.

• tags (Optional[List[str]]) – List of string tags to pass to all callbacks. These will be passed in addition to tags passed to the chain during construction, but only these runtime tags will propagate to calls to other objects.

• metadata (Optional[Dict[str, Any]]) – Optional metadata associated with the chain. Defaults to None

• include_run_info (bool) – Whether to include run info in the response. Defaults to False.

• run_name (Optional[str]) –

Returns

A dict of named outputs. Should contain all outputs specified in

Chain.output_keys.

Return type

Dict[str, Any]

async abatch(inputs: List[Input], config: Optional[Union[RunnableConfig, List[RunnableConfig]]] = None, *, return_exceptions: bool = False, **kwargs: Optional[Any]) → List[Output]

Default implementation runs ainvoke in parallel using asyncio.gather.

The default implementation of batch works well for IO bound runnables.

Subclasses should override this method if they can batch more efficiently; e.g., if the underlying Runnable uses an API which supports a batch mode.

Parameters

• inputs (List[Input]) – A list of inputs to the Runnable.

• config (Optional[Union[RunnableConfig, List[RunnableConfig]]]) – A config to use when invoking the Runnable. The config supports standard keys like ‘tags’, ‘metadata’ for tracing purposes, ‘max_concurrency’ for controlling how much work to do in parallel, and other keys. Please refer to the RunnableConfig for more details. Defaults to None.

• return_exceptions (bool) – Whether to return exceptions instead of raising them. Defaults to False.

• kwargs (Optional[Any]) – Additional keyword arguments to pass to the Runnable.

Returns

A list of outputs from the Runnable.

Return type

List[Output]

async abatch_as_completed(inputs: Sequence[Input], config: Optional[Union[RunnableConfig, Sequence[RunnableConfig]]] = None, *, return_exceptions: bool = False, **kwargs: Optional[Any]) → AsyncIterator[Tuple[int, Union[Output, Exception]]]

Run ainvoke in parallel on a list of inputs, yielding results as they complete.

Parameters

• inputs (Sequence[Input]) – A list of inputs to the Runnable.

• config (Optional[Union[RunnableConfig, Sequence[RunnableConfig]]]) – A config to use when invoking the Runnable. The config supports standard keys like ‘tags’, ‘metadata’ for tracing purposes, ‘max_concurrency’ for controlling how much work to do in parallel, and other keys. Please refer to the RunnableConfig for more details. Defaults to None. Defaults to None.

• return_exceptions (bool) – Whether to return exceptions instead of raising them. Defaults to False.

• kwargs (Optional[Any]) – Additional keyword arguments to pass to the Runnable.

Yields

A tuple of the index of the input and the output from the Runnable.

Return type

AsyncIterator[Tuple[int, Union[Output, Exception]]]

async acall(inputs: Union[Dict[str, Any], Any], return_only_outputs: bool = False, callbacks: Optional[Union[List[BaseCallbackHandler], BaseCallbackManager]] = None, *, tags: Optional[List]str] = None, metadata: Optional[Dict[str, Any]] = None, run_name: Optional[str] = None, include_run_info: bool = False) → Dict[str, Any]

Deprecated since version langchain==0.1.0: Use ainvoke instead.

Asynchronously execute the chain.

Parameters

• inputs (Union[Dict[str, Any], Any]) – Dictionary of inputs, or single input if chain expects only one param. Should contain all inputs specified in Chain.input_keys except for inputs that will be set by the chain’s memory.

• return_only_outputs (bool) – Whether to return only outputs in the response. If True, only new keys generated by this chain will be returned. If False, both input keys and new keys generated by this chain will be returned. Defaults to False.

• callbacks (Optional[Union[List[BaseCallbackHandler], BaseCallbackManager]]) – Callbacks to use for this chain run. These will be called in addition to callbacks passed to the chain during construction, but only these runtime callbacks will propagate to calls to other objects.

• tags (Optional[List[str]]) – List of string tags to pass to all callbacks. These will be passed in addition to tags passed to the chain during construction, but only these runtime tags will propagate to calls to other objects.

• metadata (Optional[Dict[str, Any]]) – Optional metadata associated with the chain. Defaults to None

• include_run_info (bool) – Whether to include run info in the response. Defaults to False.

• run_name (Optional[str]) –

Returns

A dict of named outputs. Should contain all outputs specified in

Chain.output_keys.

Return type

Dict[str, Any]

async ainvoke(input: Dict[str, Any], config: Optional[RunnableConfig] = None, **kwargs: Any) → Dict[str, Any]

Default implementation of ainvoke, calls invoke from a thread.

The default implementation allows usage of async code even if the Runnable did not implement a native async version of invoke.

Subclasses should override this method if they can run asynchronously.

Parameters

• input (Dict[str, Any]) –

• config (Optional[RunnableConfig]) –

• kwargs (Any) –

Return type

Dict[str, Any]

apply(input_list: List[Dict[str, Any]], callbacks: Optional[Union[List[BaseCallbackHandler], BaseCallbackManager]] = None) → List[Dict[str, str]]

Deprecated since version langchain==0.1.0: Use batch instead.

Call the chain on all inputs in the list.

Parameters

• input_list (List[Dict[str, Any]]) –

• callbacks (Optional[Union[List[BaseCallbackHandler], BaseCallbackManager]]) –

Return type

List[Dict[str, str]]

async aprep_inputs(inputs: Union[Dict[str, Any], Any]) → Dict[str, str]

准备链的输入，包括从内存中添加输入。

Parameters

inputs (Union[Dict[str, Any], Any]) – 原始输入的字典，或者当链只接受一个参数时，为单个输入。应包含 Chain.input_keys 中指定的所有输入，除了将由链的内存设置的输入。

Returns

包含所有输入的字典，包括链的内存添加的输入。

Return type

Dict[str, str]

async aprep_outputs(inputs: Dict[str, str], outputs: Dict[str, str], return_only_outputs: bool = False) → Dict[str, str]

验证和准备链的输出，并将关于此运行的信息保存到内存中。

Parameters

• inputs (Dict[str, str]) – 链输入的字典，包括链内存添加的任何输入。

• outputs (Dict[str, str]) – 初始链输出的字典。

• return_only_outputs (bool) – 是否仅返回链的输出。如果为 False，则输入也会添加到最终输出中。

Returns

最终链输出的字典。

Return type

Dict[str, str]

async arun(*args: Any, callbacks: Optional[Union[List[BaseCallbackHandler], BaseCallbackManager]] = None, tags: Optional[List[str]] = None, metadata: Optional[Dict[str, Any]] = None, **kwargs: Any) → Any

Deprecated since version langchain==0.1.0: Use ainvoke instead.

执行链的便捷方法。

此方法与 Chain.__call__ 之间的主要区别在于，此方法期望输入直接作为位置参数或关键字参数传入，而 Chain.__call__ 期望一个包含所有输入的单个输入字典

Parameters

• *args (Any) – 如果链只接受单个输入，则可以将其作为唯一的位置参数传入。

• callbacks (Optional[Union[List[BaseCallbackHandler], BaseCallbackManager]]) – Callbacks to use for this chain run. These will be called in addition to callbacks passed to the chain during construction, but only these runtime callbacks will propagate to calls to other objects.

• tags (Optional[List[str]]) – List of string tags to pass to all callbacks. These will be passed in addition to tags passed to the chain during construction, but only these runtime tags will propagate to calls to other objects.

• **kwargs (Any) – 如果链接受多个输入，则可以直接作为关键字参数传入。

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

• **kwargs –

Returns

链的输出。

Return type

Any

示例

# Suppose we have a single-input chain that takes a 'question' string:
await chain.arun("What's the temperature in Boise, Idaho?")
# -> "The temperature in Boise is..."

# Suppose we have a multi-input chain that takes a 'question' string
# and 'context' string:
question = "What's the temperature in Boise, Idaho?"
context = "Weather report for Boise, Idaho on 07/03/23..."
await chain.arun(question=question, context=context)
# -> "The temperature in Boise is..."

as_tool(args_schema: Optional[Type[BaseModel]] = None, *, name: Optional[str] = None, description: Optional[str] = None, arg_types: Optional[Dict[str, Type]] = None) → BaseTool

Beta

此 API 处于 Beta 阶段，未来可能会发生变化。

从 Runnable 创建一个 BaseTool。

as_tool 将从 Runnable 实例化一个包含名称、描述和 args_schema 的 BaseTool。在可能的情况下，模式会从 runnable.get_input_schema 推断。或者（例如，如果 Runnable 接受字典作为输入，并且未对特定的字典键进行类型化），可以使用 args_schema 直接指定模式。您也可以传递 arg_types 以仅指定必需的参数及其类型。

Parameters

• args_schema (Optional[Type[BaseModel]]) – 工具的模式。默认为 None。

• name (Optional[str]) – 工具的名称。默认为 None。

• description (Optional[str]) – 工具的描述。默认为 None。

• arg_types (Optional[Dict[str, Type]]) – 参数名称到类型的字典。默认为 None。

Returns

BaseTool 实例。

Return type

BaseTool

类型化字典输入

from typing import List
from typing_extensions import TypedDict
from langchain_core.runnables import RunnableLambda

class Args(TypedDict):
    a: int
    b: List[int]

def f(x: Args) -> str:
    return str(x["a"] * max(x["b"]))

runnable = RunnableLambda(f)
as_tool = runnable.as_tool()
as_tool.invoke({"a": 3, "b": [1, 2]})

dict 输入，通过 args_schema 指定模式

from typing import Any, Dict, List
from langchain_core.pydantic_v1 import BaseModel, Field
from langchain_core.runnables import RunnableLambda

def f(x: Dict[str, Any]) -> str:
    return str(x["a"] * max(x["b"]))

class FSchema(BaseModel):
    """Apply a function to an integer and list of integers."""

    a: int = Field(..., description="Integer")
    b: List[int] = Field(..., description="List of ints")

runnable = RunnableLambda(f)
as_tool = runnable.as_tool(FSchema)
as_tool.invoke({"a": 3, "b": [1, 2]})

dict 输入，通过 arg_types 指定模式

from typing import Any, Dict, List
from langchain_core.runnables import RunnableLambda

def f(x: Dict[str, Any]) -> str:
    return str(x["a"] * max(x["b"]))

runnable = RunnableLambda(f)
as_tool = runnable.as_tool(arg_types={"a": int, "b": List[int]})
as_tool.invoke({"a": 3, "b": [1, 2]})

字符串输入

from langchain_core.runnables import RunnableLambda

def f(x: str) -> str:
    return x + "a"

def g(x: str) -> str:
    return x + "z"

runnable = RunnableLambda(f) | g
as_tool = runnable.as_tool()
as_tool.invoke("b")

0.2.14 版本新增。

async astream(input: Input, config: Optional[RunnableConfig] = None, **kwargs: Optional[Any]) → AsyncIterator[Output]

astream 的默认实现，它调用 ainvoke。如果子类支持流式输出，则应覆盖此方法。

Parameters

• input (Input) – Runnable 的输入。

• config (Optional[RunnableConfig]) – 用于 Runnable 的配置。默认为 None。

• kwargs (Optional[Any]) – Additional keyword arguments to pass to the Runnable.

Yields

Runnable 的输出。

Return type

AsyncIterator[Output]

astream_events(input: Any, config: Optional[RunnableConfig] = None, *, version: Literal['v1', 'v2'], include_names: Optional[Sequence[str]] = None, include_types: Optional[Sequence[str]] = None, include_tags: Optional[Sequence[str]] = None, exclude_names: Optional[Sequence[str]] = None, exclude_types: Optional[Sequence[str]] = None, exclude_tags: Optional[Sequence[str]] = None, **kwargs: Any) → AsyncIterator[Union[StandardStreamEvent, CustomStreamEvent]]

Beta

此 API 处于 Beta 阶段，未来可能会发生变化。

生成事件流。

用于创建一个迭代器，遍历 StreamEvents，这些 StreamEvents 提供关于 Runnable 进度的实时信息，包括来自中间结果的 StreamEvents。

StreamEvent 是一个具有以下模式的字典

• event: str - 事件名称的格式为：

  格式：on_[runnable_type]_(start|stream|end)。

• name: str - 生成事件的 Runnable 的名称。

• run_id: str - 随机生成的 ID，与发出事件的 Runnable 的给定执行相关联。作为父 Runnable 执行的一部分而调用的子 Runnable 会被分配其自己的唯一 ID。

  的 Runnable，该 Runnable 发出事件。作为父 Runnable 执行的一部分调用的子 Runnable 会被分配其自己的唯一 ID。

• parent_ids: List[str] - 生成事件的父 runnable 的 ID。根 Runnable 将具有一个空列表。父 ID 的顺序是从根到直接父级。仅适用于 API 的 v2 版本。API 的 v1 版本将返回一个空列表。

  generated the event. The root Runnable will have an empty list. The order of the parent IDs is from the root to the immediate parent. Only available for v2 version of the API. The v1 version of the API will return an empty list.

• tags: Optional[List[str]] - 生成事件的 Runnable 的标签。

  the event.

• metadata: Optional[Dict[str, Any]] - 生成事件的 Runnable 的元数据。

  that generated the event.

• data: Dict[str, Any]

下面是一个表格，说明了各种链可能发出的一些事件。为了简洁起见，表格中省略了元数据字段。链定义已包含在表格之后。

注意 此参考表适用于 V2 版本的模式。

事件	名称	块	输入	输出
on_chat_model_start	[模型名称]		{“messages”: [[SystemMessage, HumanMessage]]}
on_chat_model_stream	[模型名称]	AIMessageChunk(content=”hello”)
on_chat_model_end	[模型名称]		{“messages”: [[SystemMessage, HumanMessage]]}	AIMessageChunk(content=”hello world”)
on_llm_start	[模型名称]		{‘input’: ‘hello’}
on_llm_stream	[模型名称]	‘Hello’
on_llm_end	[模型名称]		‘Hello human!’
on_chain_start	format_docs
on_chain_stream	format_docs	“hello world!, goodbye world!”
on_chain_end	format_docs		[Document(…)]	“hello world!, goodbye world!”
on_tool_start	some_tool		{“x”: 1, “y”: “2”}
on_tool_end	some_tool			{“x”: 1, “y”: “2”}
on_retriever_start	[检索器名称]		{“query”: “hello”}
on_retriever_end	[检索器名称]		{“query”: “hello”}	[Document(…), ..]
on_prompt_start	[模板名称]		{“question”: “hello”}
on_prompt_end	[模板名称]		{“question”: “hello”}	ChatPromptValue(messages: [SystemMessage, …])

除了标准事件之外，用户还可以调度自定义事件（请参阅下面的示例）。

自定义事件将仅在 API 的 v2 版本中显示！

自定义事件具有以下格式

属性	类型	描述
名称	str	用户定义的事件名称。
data	Any	与事件关联的数据。这可以是任何内容，但我们建议使其为 JSON 可序列化。

以下是与上面显示的标准事件关联的声明

format_docs:

def format_docs(docs: List[Document]) -> str:
    '''Format the docs.'''
    return ", ".join([doc.page_content for doc in docs])

format_docs = RunnableLambda(format_docs)

some_tool:

@tool
def some_tool(x: int, y: str) -> dict:
    '''Some_tool.'''
    return {"x": x, "y": y}

prompt:

template = ChatPromptTemplate.from_messages(
    [("system", "You are Cat Agent 007"), ("human", "{question}")]
).with_config({"run_name": "my_template", "tags": ["my_template"]})

示例

from langchain_core.runnables import RunnableLambda

async def reverse(s: str) -> str:
    return s[::-1]

chain = RunnableLambda(func=reverse)

events = [
    event async for event in chain.astream_events("hello", version="v2")
]

# will produce the following events (run_id, and parent_ids
# has been omitted for brevity):
[
    {
        "data": {"input": "hello"},
        "event": "on_chain_start",
        "metadata": {},
        "name": "reverse",
        "tags": [],
    },
    {
        "data": {"chunk": "olleh"},
        "event": "on_chain_stream",
        "metadata": {},
        "name": "reverse",
        "tags": [],
    },
    {
        "data": {"output": "olleh"},
        "event": "on_chain_end",
        "metadata": {},
        "name": "reverse",
        "tags": [],
    },
]

示例：调度自定义事件

from langchain_core.callbacks.manager import (
    adispatch_custom_event,
)
from langchain_core.runnables import RunnableLambda, RunnableConfig
import asyncio


async def slow_thing(some_input: str, config: RunnableConfig) -> str:
    """Do something that takes a long time."""
    await asyncio.sleep(1) # Placeholder for some slow operation
    await adispatch_custom_event(
        "progress_event",
        {"message": "Finished step 1 of 3"},
        config=config # Must be included for python < 3.10
    )
    await asyncio.sleep(1) # Placeholder for some slow operation
    await adispatch_custom_event(
        "progress_event",
        {"message": "Finished step 2 of 3"},
        config=config # Must be included for python < 3.10
    )
    await asyncio.sleep(1) # Placeholder for some slow operation
    return "Done"

slow_thing = RunnableLambda(slow_thing)

async for event in slow_thing.astream_events("some_input", version="v2"):
    print(event)

Parameters

• input (Any) – Runnable 的输入。

• config (Optional[RunnableConfig]) – 用于 Runnable 的配置。

• version (Literal['v1', 'v2']) – 要使用的模式版本，可以是 v2 或 v1。用户应使用 v2。v1 用于向后兼容，将在 0.4.0 中弃用。在 API 稳定之前，不会分配默认值。自定义事件将仅在 v2 中显示。

• include_names (Optional[Sequence[str]]) – 仅包括来自具有匹配名称的 runnable 的事件。

• include_types (Optional[Sequence[str]]) – 仅包括来自具有匹配类型的 runnable 的事件。

• include_tags (Optional[Sequence[str]]) – 仅包括来自具有匹配标签的 runnable 的事件。

• exclude_names (Optional[Sequence[str]]) – 排除来自具有匹配名称的 runnable 的事件。

• exclude_types (Optional[Sequence[str]]) – 排除来自具有匹配类型的 runnable 的事件。

• exclude_tags (Optional[Sequence[str]]) – 排除来自具有匹配标签的 runnable 的事件。

• kwargs (Any) – 要传递给 Runnable 的其他关键字参数。这些参数将传递给 astream_log，因为此 astream_events 的实现构建于 astream_log 之上。

Yields

StreamEvents 的异步流。

Raises

NotImplementedError – 如果版本不是 v1 或 v2，则引发此错误。

Return type

AsyncIterator[Union[StandardStreamEvent, CustomStreamEvent]]

batch(inputs: List[Input], config: Optional[Union[RunnableConfig, List[RunnableConfig]]] = None, *, return_exceptions: bool = False, **kwargs: Optional[Any]) → List[Output]

默认实现使用线程池执行器并行运行 invoke。

The default implementation of batch works well for IO bound runnables.

Subclasses should override this method if they can batch more efficiently; e.g., if the underlying Runnable uses an API which supports a batch mode.

Parameters

• inputs (List[Input]) –

• config (Optional[Union[RunnableConfig, List[RunnableConfig]]]) –

• return_exceptions (bool) –

• kwargs (Optional[Any]) –

Return type

List[Output]

batch_as_completed(inputs: Sequence[Input], config: Optional[Union[RunnableConfig, Sequence[RunnableConfig]]] = None, *, return_exceptions: bool = False, **kwargs: Optional[Any]) → Iterator[Tuple[int, Union[Output, Exception]]]

并行运行 invoke 处理输入列表，并在完成时生成结果。

Parameters

• inputs (Sequence[Input]) –

• config (Optional[Union[RunnableConfig, Sequence[RunnableConfig]]]) –

• return_exceptions (bool) –

• kwargs (Optional[Any]) –

Return type

Iterator[Tuple[int, Union[Output, Exception]]]

configurable_alternatives(which: ConfigurableField, *, default_key: str = 'default', prefix_keys: bool = False, **kwargs: Union[Runnable[Input, Output], Callable[[], Runnable[Input, Output]]]) → RunnableSerializable[Input, Output]

配置可在运行时设置的 Runnable 的备选项。

Parameters

• which (ConfigurableField) – 将用于选择备选项的 ConfigurableField 实例。

• default_key (str) – 如果未选择备选项，则使用的默认键。默认为 “default”。

• prefix_keys (bool) – 是否使用 ConfigurableField id 作为键的前缀。默认为 False。

• **kwargs** (Union[Runnable[Input, Output], Callable[[], Runnable[Input, Output]]]) – 键值对字典，键可以是 Runnable 实例或返回 Runnable 实例的可调用对象。

Returns

配置了备选项的新 Runnable。

Return type

RunnableSerializable[Input, Output]

from langchain_anthropic import ChatAnthropic
from langchain_core.runnables.utils import ConfigurableField
from langchain_openai import ChatOpenAI

model = ChatAnthropic(
    model_name="claude-3-sonnet-20240229"
).configurable_alternatives(
    ConfigurableField(id="llm"),
    default_key="anthropic",
    openai=ChatOpenAI()
)

# uses the default model ChatAnthropic
print(model.invoke("which organization created you?").content)

# uses ChatOpenAI
print(
    model.with_config(
        configurable={"llm": "openai"}
    ).invoke("which organization created you?").content
)

configurable_fields(**kwargs: Union[ConfigurableField, ConfigurableFieldSingleOption, ConfigurableFieldMultiOption]) → RunnableSerializable[Input, Output]

在运行时配置特定的 Runnable 字段。

Parameters

**kwargs** (Union[ConfigurableField, ConfigurableFieldSingleOption, ConfigurableFieldMultiOption]) – 用于配置的 ConfigurableField 实例字典。

Returns

配置了字段的新 Runnable。

Return type

RunnableSerializable[Input, Output]

from langchain_core.runnables import ConfigurableField
from langchain_openai import ChatOpenAI

model = ChatOpenAI(max_tokens=20).configurable_fields(
    max_tokens=ConfigurableField(
        id="output_token_number",
        name="Max tokens in the output",
        description="The maximum number of tokens in the output",
    )
)

# max_tokens = 20
print(
    "max_tokens_20: ",
    model.invoke("tell me something about chess").content
)

# max_tokens = 200
print("max_tokens_200: ", model.with_config(
    configurable={"output_token_number": 200}
    ).invoke("tell me something about chess").content
)

invoke(input: Dict[str, Any], config: Optional[RunnableConfig] = None, **kwargs: Any) → Dict[str, Any]

将单个输入转换为输出。重写此方法以实现。

Parameters

• input (Dict[str, Any]) – Runnable 的输入。

• config (Optional[RunnableConfig]) – 调用 Runnable 时使用的配置。该配置支持标准键，如 ‘tags’、‘metadata’（用于追踪目的）、‘max_concurrency’（用于控制并行执行的工作量）以及其他键。请参阅 RunnableConfig 以获取更多详细信息。

• kwargs (Any) –

Returns

Runnable 的输出。

Return type

Dict[str, Any]

prep_inputs(inputs: Union[Dict[str, Any], Any]) → Dict[str, str]

准备链的输入，包括从内存中添加输入。

Parameters

inputs (Union[Dict[str, Any], Any]) – 原始输入的字典，或者当链只接受一个参数时，为单个输入。应包含 Chain.input_keys 中指定的所有输入，除了将由链的内存设置的输入。

Returns

包含所有输入的字典，包括链的内存添加的输入。

Return type

Dict[str, str]

prep_outputs(inputs: Dict[str, str], outputs: Dict[str, str], return_only_outputs: bool = False) → Dict[str, str]

验证和准备链的输出，并将关于此运行的信息保存到内存中。

Parameters

• inputs (Dict[str, str]) – 链输入的字典，包括链内存添加的任何输入。

• outputs (Dict[str, str]) – 初始链输出的字典。

• return_only_outputs (bool) – 是否仅返回链的输出。如果为 False，则输入也会添加到最终输出中。

Returns

最终链输出的字典。

Return type

Dict[str, str]

run(*args: Any, callbacks: Optional[Union[List[BaseCallbackHandler], BaseCallbackManager]] = None, tags: Optional[List[str]] = None, metadata: Optional[Dict[str, Any]] = None, **kwargs: Any) → Any

Deprecated since version langchain==0.1.0: Use invoke instead.

执行链的便捷方法。

此方法与 Chain.__call__ 之间的主要区别在于，此方法期望输入直接作为位置参数或关键字参数传入，而 Chain.__call__ 期望一个包含所有输入的单个输入字典

Parameters

• *args (Any) – 如果链只接受单个输入，则可以将其作为唯一的位置参数传入。

• callbacks (Optional[Union[List[BaseCallbackHandler], BaseCallbackManager]]) – Callbacks to use for this chain run. These will be called in addition to callbacks passed to the chain during construction, but only these runtime callbacks will propagate to calls to other objects.

• tags (Optional[List[str]]) – List of string tags to pass to all callbacks. These will be passed in addition to tags passed to the chain during construction, but only these runtime tags will propagate to calls to other objects.

• **kwargs (Any) – 如果链接受多个输入，则可以直接作为关键字参数传入。

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

• **kwargs –

Returns

链的输出。

Return type

Any

示例

# Suppose we have a single-input chain that takes a 'question' string:
chain.run("What's the temperature in Boise, Idaho?")
# -> "The temperature in Boise is..."

# Suppose we have a multi-input chain that takes a 'question' string
# and 'context' string:
question = "What's the temperature in Boise, Idaho?"
context = "Weather report for Boise, Idaho on 07/03/23..."
chain.run(question=question, context=context)
# -> "The temperature in Boise is..."

save(file_path: Union[Path, str]) → None

保存链。

期望实现 Chain._chain_type 属性，并且内存为空。

null。

Parameters

file_path (Union[Path, str]) – 保存链的文件路径。

Return type

None

示例

chain.save(file_path="path/chain.yaml")

stream(input: Input, config: Optional[RunnableConfig] = None, **kwargs: Optional[Any]) → Iterator[Output]

stream 的默认实现，它调用 invoke。如果子类支持流式输出，则应重写此方法。

Parameters

• input (Input) – Runnable 的输入。

• config (Optional[RunnableConfig]) – 用于 Runnable 的配置。默认为 None。

• kwargs (Optional[Any]) – Additional keyword arguments to pass to the Runnable.

Yields

Runnable 的输出。

Return type

Iterator[Output]

to_json() → Union[SerializedConstructor, SerializedNotImplemented]

将 Runnable 序列化为 JSON。

Returns

Runnable 的 JSON 可序列化表示形式。

Return type

Union[SerializedConstructor, SerializedNotImplemented]