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langchain/langchain/agents/loading.py

113 lines
4.2 KiB
Python

"""Functionality for loading agents."""
import json
from pathlib import Path
from typing import Any, List, Optional, Union
import yaml
from langchain.agents.agent import Agent
from langchain.agents.agent_types import AgentType
from langchain.agents.chat.base import ChatAgent
from langchain.agents.conversational.base import ConversationalAgent
from langchain.agents.conversational_chat.base import ConversationalChatAgent
from langchain.agents.mrkl.base import ZeroShotAgent
from langchain.agents.react.base import ReActDocstoreAgent
from langchain.agents.self_ask_with_search.base import SelfAskWithSearchAgent
from langchain.agents.tools import Tool
from langchain.chains.loading import load_chain, load_chain_from_config
from langchain.llms.base import BaseLLM
from langchain.utilities.loading import try_load_from_hub
AGENT_TO_CLASS = {
AgentType.ZERO_SHOT_REACT_DESCRIPTION: ZeroShotAgent,
AgentType.REACT_DOCSTORE: ReActDocstoreAgent,
AgentType.SELF_ASK_WITH_SEARCH: SelfAskWithSearchAgent,
AgentType.CONVERSATIONAL_REACT_DESCRIPTION: ConversationalAgent,
AgentType.CHAT_ZERO_SHOT_REACT_DESCRIPTION: ChatAgent,
AgentType.CHAT_CONVERSATIONAL_REACT_DESCRIPTION: ConversationalChatAgent,
}
URL_BASE = "https://raw.githubusercontent.com/hwchase17/langchain-hub/master/agents/"
def _load_agent_from_tools(
config: dict, llm: BaseLLM, tools: List[Tool], **kwargs: Any
) -> Agent:
config_type = config.pop("_type")
if config_type not in AGENT_TO_CLASS:
raise ValueError(f"Loading {config_type} agent not supported")
if config_type not in AGENT_TO_CLASS:
raise ValueError(f"Loading {config_type} agent not supported")
agent_cls = AGENT_TO_CLASS[config_type]
combined_config = {**config, **kwargs}
return agent_cls.from_llm_and_tools(llm, tools, **combined_config)
def load_agent_from_config(
config: dict,
llm: Optional[BaseLLM] = None,
tools: Optional[List[Tool]] = None,
**kwargs: Any,
) -> Agent:
"""Load agent from Config Dict."""
if "_type" not in config:
raise ValueError("Must specify an agent Type in config")
load_from_tools = config.pop("load_from_llm_and_tools", False)
if load_from_tools:
if llm is None:
raise ValueError(
"If `load_from_llm_and_tools` is set to True, "
"then LLM must be provided"
)
if tools is None:
raise ValueError(
"If `load_from_llm_and_tools` is set to True, "
"then tools must be provided"
)
return _load_agent_from_tools(config, llm, tools, **kwargs)
config_type = config.pop("_type")
if config_type not in AGENT_TO_CLASS:
raise ValueError(f"Loading {config_type} agent not supported")
agent_cls = AGENT_TO_CLASS[config_type]
if "llm_chain" in config:
config["llm_chain"] = load_chain_from_config(config.pop("llm_chain"))
elif "llm_chain_path" in config:
config["llm_chain"] = load_chain(config.pop("llm_chain_path"))
else:
raise ValueError("One of `llm_chain` and `llm_chain_path` should be specified.")
combined_config = {**config, **kwargs}
return agent_cls(**combined_config) # type: ignore
def load_agent(path: Union[str, Path], **kwargs: Any) -> Agent:
"""Unified method for loading a agent from LangChainHub or local fs."""
if hub_result := try_load_from_hub(
path, _load_agent_from_file, "agents", {"json", "yaml"}
):
return hub_result
else:
return _load_agent_from_file(path, **kwargs)
def _load_agent_from_file(file: Union[str, Path], **kwargs: Any) -> Agent:
"""Load agent from file."""
# Convert file to Path object.
if isinstance(file, str):
file_path = Path(file)
else:
file_path = file
# Load from either json or yaml.
if file_path.suffix == ".json":
with open(file_path) as f:
config = json.load(f)
elif file_path.suffix == ".yaml":
with open(file_path, "r") as f:
config = yaml.safe_load(f)
else:
raise ValueError("File type must be json or yaml")
# Load the agent from the config now.
return load_agent_from_config(config, **kwargs)