multi_prompt.py — langchain Source File

Source Code

"""Use a single chain to route an input to one of multiple llm chains."""

from __future__ import annotations

from typing import Any

from langchain_core._api import deprecated
from langchain_core.language_models import BaseLanguageModel
from langchain_core.prompts import PromptTemplate
from typing_extensions import override

from langchain_classic.chains import ConversationChain
from langchain_classic.chains.base import Chain
from langchain_classic.chains.llm import LLMChain
from langchain_classic.chains.router.base import MultiRouteChain
from langchain_classic.chains.router.llm_router import (
    LLMRouterChain,
    RouterOutputParser,
)
from langchain_classic.chains.router.multi_prompt_prompt import (
    MULTI_PROMPT_ROUTER_TEMPLATE,
)


@deprecated(
    since="0.2.12",
    removal="1.0",
    message=(
        "Please see migration guide here for recommended implementation: "
        "https://python.langchain.com/docs/versions/migrating_chains/multi_prompt_chain/"
    ),
)
class MultiPromptChain(MultiRouteChain):
    """A multi-route chain that uses an LLM router chain to choose amongst prompts.

    This class is deprecated. See below for a replacement, which offers several
    benefits, including streaming and batch support.

    Below is an example implementation:

        ```python
        from operator import itemgetter
        from typing import Literal

        from langchain_core.output_parsers import StrOutputParser
        from langchain_core.prompts import ChatPromptTemplate
        from langchain_core.runnables import RunnableConfig
        from langchain_openai import ChatOpenAI
        from langgraph.graph import END, START, StateGraph
        from typing_extensions import TypedDict

        model = ChatOpenAI(model="gpt-4o-mini")

        # Define the prompts we will route to
        prompt_1 = ChatPromptTemplate.from_messages(
            [
                ("system", "You are an expert on animals."),
                ("human", "{input}"),
            ]
        )
// ... (131 more lines)