Source code for langchain_prompty.langchain
from typing import Any, Dict
from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder
from langchain_core.runnables import Runnable, RunnableLambda
from .parsers import RoleMap
from .utils import load, prepare
[docs]def create_chat_prompt(
path: str,
input_name_agent_scratchpad: str = "agent_scratchpad",
) -> Runnable[Dict[str, Any], ChatPromptTemplate]:
"""Create a chat prompt from a Langchain schema."""
def runnable_chat_lambda(inputs: Dict[str, Any]) -> ChatPromptTemplate:
p = load(path)
parsed = prepare(p, inputs)
# Parsed messages have been templated
# Convert to Message objects to avoid templating attempts in ChatPromptTemplate
lc_messages = []
for message in parsed:
message_class = RoleMap.get_message_class(message["role"])
lc_messages.append(message_class(content=message["content"]))
lc_messages.append(
MessagesPlaceholder(
variable_name=input_name_agent_scratchpad, optional=True
) # type: ignore[arg-type]
)
lc_p = ChatPromptTemplate.from_messages(lc_messages)
lc_p = lc_p.partial(**p.inputs)
return lc_p
return RunnableLambda(runnable_chat_lambda)