LCEL中RunnableParallel 怎么设置最大并发数

[shell-nlp]

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Example Code

qa_bot_with_docs = (
    RunnableParallel(
        {
            "context": itemgetter("question")
            | contextual_rerank_retriever,  # 如果在这里直接变为 str的话 后面无法实现返回 docs的详细信息
            "question": itemgetter("question"),
        }
    )
    | RunnableParallel(
        answer=qa_bot,
        prompt=prompt,
        gen_question=gem_question_chain,
        event=event_extraction_chain,
        org=org_extraction_chain,
        human=human_extraction_chain,
        mind=mind_extraction_chain,
    ).with_config(config={"max_concurrency": 2})

Description

我想让RunnableParallel 部分最大并发为2，即先执行answer、prompt，若prompt执行完成，则执行gen_question，以此类推，最大同时执行两个子chain

System Info

System Information

OS: Linux
OS Version: #101~20.04.1-Ubuntu SMP Thu Nov 16 14:22:28 UTC 2023
Python Version: 3.10.9 (main, Mar 1 2023, 18:23:06) [GCC 11.2.0]

Package Information

langchain_core: 0.2.28
langchain: 0.2.9
langchain_community: 0.2.7
langsmith: 0.1.85
langchain_experimental: 0.0.62
langchain_openai: 0.1.7
langchain_text_splitters: 0.2.2
langchainhub: 0.1.14
langgraph: 0.1.8

Packages not installed (Not Necessarily a Problem)

The following packages were not found:

langserve

[dosubot[bot]]

要在LCEL中将RunnableParallel的最大并发数设置为2，可以在调用链时使用config参数。以下是一个示例代码：

from langchain_core.runnables import RunnableLambda, RunnableParallel

runnable1 = RunnableLambda(lambda x: {"foo": x})
runnable2 = RunnableLambda(lambda x: [x] * 2)

chain = RunnableParallel(first=runnable1, second=runnable2)

chain.invoke(2, config={"max_concurrency": 2})

在你的代码中，可以这样设置：

qa_bot_with_docs = (
    RunnableParallel(
        {
            "context": itemgetter("question") | contextual_rerank_retriever,
            "question": itemgetter("question"),
        }
    )
    | RunnableParallel(
        answer=qa_bot,
        prompt=prompt,
        gen_question=gem_question_chain,
        event=event_extraction_chain,
        org=org_extraction_chain,
        human=human_extraction_chain,
        mind=mind_extraction_chain,
    ).with_config(config={"max_concurrency": 2})
)

这样设置后，RunnableParallel部分的最大并发数将被限制为2^[1].

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[shell-nlp]

但是我经过测试发现，max_concurrency 并没有生效

[shell-nlp]

查看源码后，现阶段并不支持