instrument langchain

[codefromthecrypt]

I have the following program and I'd love to be able to showcase this or similar with LangTrace!

const {ChatOpenAI, OpenAIEmbeddings} = require("@langchain/openai");
const {MemoryVectorStore} = require("langchain/vectorstores/memory");
const {ChatPromptTemplate} = require("@langchain/core/prompts");
const {StringOutputParser} = require("@langchain/core/output_parsers");
const {RunnablePassthrough, RunnableSequence} = require("@langchain/core/runnables");

async function main() {
    const llm = new ChatOpenAI({model: 'qwen2.5:0.5b'});
    const embeddings = new OpenAIEmbeddings({model: 'all-minilm:33m'});

    const monsters = [
        "Goblin: Weak but numerous, attacks in groups.",
        "Orc: Strong and aggressive, fights head-on.",
        "Skeleton: Undead warrior, immune to poison but fragile.",
        "Giant Spider: Webs players, poisonous bite.",
        "Dragon: Powerful and magical, breathes fire.",
        "Keegorg: Senior Solution Architect at Docker",
    ].map((pageContent) => ({ pageContent, metadata: {} }));

    const vectorStore = new MemoryVectorStore(embeddings);
    // Create embeddings for the monsters
    await vectorStore.addDocuments(monsters);

    // Retrieve only one monster
    const retriever = vectorStore.asRetriever(1);

    // Create prompt template
    const ANSWER_PROMPT = ChatPromptTemplate.fromTemplate(
        `You are a monster expert, and the context includes relevant monsters. Answer the user concisely only using the provided context. If you don't know the answer, just say that you don't know.
        context: {context}
        Question: "{question}"
        Answer:`
    );

    function onlyContent(docs) {
        return docs.map(doc => doc.page_content).join('\n\n');
    }

    const chain = RunnableSequence.from([
        {
            context: retriever.pipe(onlyContent),
            question: new RunnablePassthrough(),
        },
        ANSWER_PROMPT,
        llm,
        new StringOutputParser(),
    ]);

    // Pass the user's question to the sequence
    const response = await chain.invoke("Who is Keegorg?");
    console.log(response);
}

main();

[karthikscale3]

@codefromthecrypt - Thanks for the issue. We tried instrumenting langchain's typescript sdk but we ran into a bunch of issues with the way the library is set up. We realized majority of langchain ecosystem is on python and as a result we have decided not to support langchain's typescript sdk at this point of time. But, will keep you posted if that changes.

[codefromthecrypt]

fyi this might help in the future https://github.com/langchain-ai/langchain/discussions/27954

[karthikscale3]

Thanks @codefromthecrypt - just upvoted