langchain/templates/rag-milvus/rag_milvus/chain.py
ChengZi 2443e85533
docs: fix milvus import and update template (#22306)
docs: fix milvus import problem
update milvus-rag template with milvus-lite

Signed-off-by: ChengZi <chen.zhang@zilliz.com>
2024-05-30 08:28:55 -07:00

80 lines
2.4 KiB
Python

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
from langchain_milvus.vectorstores import Milvus
from langchain_openai import ChatOpenAI, OpenAIEmbeddings
# Example for document loading (from url), splitting, and creating vectorstore
# Setting the URI as a local file, e.g.`./milvus.db`, is the most convenient method,
# as it automatically utilizes Milvus Lite to store all data in this file.
#
# If you have large scale of data such as more than a million docs,
# we recommend setting up a more performant Milvus server on docker or kubernetes.
# (https://milvus.io/docs/quickstart.md)
# When using this setup, please use the server URI,
# e.g.`http://localhost:19530`, as your URI.
URI = "./milvus.db"
"""
# 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 = Milvus.from_documents(documents=all_splits,
collection_name="rag_milvus",
embedding=OpenAIEmbeddings(),
drop_old=True,
connection_args={"uri": URI},
)
retriever = vectorstore.as_retriever()
"""
# Embed a single document as a test
vectorstore = Milvus.from_texts(
["harrison worked at kensho"],
collection_name="rag_milvus",
embedding=OpenAIEmbeddings(),
drop_old=True,
connection_args={"uri": URI},
)
retriever = vectorstore.as_retriever()
# RAG prompt
template = """Answer the question based only on the following context:
{context}
Question: {question}
"""
prompt = ChatPromptTemplate.from_template(template)
# LLM
model = ChatOpenAI()
# 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)