packages/rag-chroma/rag_chroma/chain.py

#from langchain_community.chat_models import ChatOpenAI
from langchain_together.embeddings import TogetherEmbeddings
from langchain_together import Together
from langchain_community.vectorstores import Chroma
from langchain_core.output_parsers import StrOutputParser
from langchain_core.prompts import ChatPromptTemplate
from langchain_core.pydantic_v1 import BaseModel
from langchain_core.runnables import RunnableParallel, RunnablePassthrough

import os
from dotenv import load_dotenv
load_dotenv()
together_api_key = os.getenv("TOGETHER_API_KEY")


embeddings = TogetherEmbeddings(model="togethercomputer/m2-bert-80M-2k-retrieval")



# Example for document loading (from url), splitting, and creating vectostore

""" 
# Load
from langchain_community.document_loaders import WebBaseLoader
loader = WebBaseLoader("https://lilianweng.github.io/posts/2023-06-23-agent/")
data = loader.load()

# Split
from langchain_text_splitters import RecursiveCharacterTextSplitter
text_splitter = RecursiveCharacterTextSplitter(chunk_size=500, chunk_overlap=0)
all_splits = text_splitter.split_documents(data)

# Add to vectorDB
vectorstore = Chroma.from_documents(documents=all_splits, 
                                    collection_name="rag-chroma",
                                    embedding=OpenAIEmbeddings(),
                                    )
retriever = vectorstore.as_retriever()
"""

""" # Embed a single document as a test
vectorstore = Chroma.from_texts(
    ["harrison worked at kensho"],
    collection_name="rag-chroma",
    embedding=OpenAIEmbeddings(),
)
retriever = vectorstore.as_retriever() """


# Load up vector-store
vectorstore = Chroma(persist_directory="packages/rag-chroma/rag_chroma/vecdb",
                     collection_name="rag-chroma",
                     embedding_function = embeddings)


retriever = vectorstore.as_retriever(search_type="mmr", search_kwargs={'k': 7})


# RAG prompt
template = """Answer the question based only on the following context:
{context}

Question: {question}
"""
prompt = ChatPromptTemplate.from_template(template)

# LLM
model  = Together(
    #model="mistralai/Mistral-7B-Instruct-v0.2",
    model="mistralai/Mixtral-8x7B-Instruct-v0.1",
    temperature=0.7,
    top_k=50,
    top_p=0.7,
    repetition_penalty=1,
    together_api_key=together_api_key
)

# RAG chain
chain = (
    RunnableParallel({"context": retriever, "question": RunnablePassthrough()})
    | prompt
    | model
    | StrOutputParser()
)


# Add typing for input
class Question(BaseModel):
    __root__: str


chain = chain.with_types(input_type=Question)