Adding memory
This shows how to add memory to an arbitrary chain. Right now, you can use the memory classes but need to hook it up manually
from operator import itemgetter
from langchain.memory import ConversationBufferMemory
from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder
from langchain_core.runnables import RunnableLambda, RunnablePassthrough
from langchain_openai import ChatOpenAI
model = ChatOpenAI()
prompt = ChatPromptTemplate.from_messages(
[
("system", "You are a helpful chatbot"),
MessagesPlaceholder(variable_name="history"),
("human", "{input}"),
]
)
memory = ConversationBufferMemory(return_messages=True)
memory.load_memory_variables({})
{'history': []}
chain = (
RunnablePassthrough.assign(
history=RunnableLambda(memory.load_memory_variables) | itemgetter("history")
)
| prompt
| model
)
inputs = {"input": "hi im bob"}
response = chain.invoke(inputs)
response
AIMessage(content='Hello Bob! How can I assist you today?', additional_kwargs={}, example=False)
memory.save_context(inputs, {"output": response.content})
memory.load_memory_variables({})
{'history': [HumanMessage(content='hi im bob', additional_kwargs={}, example=False),
AIMessage(content='Hello Bob! How can I assist you today?', additional_kwargs={}, example=False)]}
inputs = {"input": "whats my name"}
response = chain.invoke(inputs)
response
AIMessage(content='Your name is Bob.', additional_kwargs={}, example=False)