refractor agents (#100)

* refractor agents

* minor cosmetic, add terminal ui for cli

* pump to 0.3.4

* Add temporary path

* fix unclose files in tests

---------

Co-authored-by: trducng <trungduc1992@gmail.com>

knowledgehub/agents/langchain_based.py

@@ -0,0 +1,81 @@
+from typing import List, Optional
+
+from langchain.agents import AgentType as LCAgentType
+from langchain.agents import initialize_agent
+from langchain.agents.agent import AgentExecutor as LCAgentExecutor
+
+from kotaemon.llms import LLM, ChatLLM
+
+from .base import BaseAgent
+from .io import AgentOutput, AgentType
+from .tools import BaseTool
+
+
+class LangchainAgent(BaseAgent):
+    """Wrapper for Langchain Agent"""
+
+    name: str = "LangchainAgent"
+    agent_type: AgentType
+    description: str = "LangchainAgent for answering multi-step reasoning questions"
+    AGENT_TYPE_MAP = {
+        AgentType.openai: LCAgentType.OPENAI_FUNCTIONS,
+        AgentType.openai_multi: LCAgentType.OPENAI_MULTI_FUNCTIONS,
+        AgentType.react: LCAgentType.ZERO_SHOT_REACT_DESCRIPTION,
+        AgentType.self_ask: LCAgentType.SELF_ASK_WITH_SEARCH,
+    }
+    agent: Optional[LCAgentExecutor] = None
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+        if self.agent_type not in self.AGENT_TYPE_MAP:
+            raise NotImplementedError(
+                f"AgentType {self.agent_type } not supported by Langchain wrapper"
+            )
+        self.update_agent_tools()
+
+    def update_agent_tools(self):
+        assert isinstance(self.llm, (ChatLLM, LLM))
+        langchain_plugins = [tool.to_langchain_format() for tool in self.plugins]
+
+        # a fix for search_doc tool name:
+        # use "Intermediate Answer" for self-ask agent
+        found_search_tool = False
+        if self.agent_type == AgentType.self_ask:
+            for plugin in langchain_plugins:
+                if plugin.name == "search_doc":
+                    plugin.name = "Intermediate Answer"
+                    langchain_plugins = [plugin]
+                    found_search_tool = True
+                    break
+
+        if self.agent_type != AgentType.self_ask or found_search_tool:
+            # reinit Langchain AgentExecutor
+            self.agent = initialize_agent(
+                langchain_plugins,
+                # TODO: could cause bugs for non-langchain llms
+                # related to https://github.com/Cinnamon/kotaemon/issues/73
+                self.llm._obj,  # type: ignore
+                agent=self.AGENT_TYPE_MAP[self.agent_type],
+                handle_parsing_errors=True,
+                verbose=True,
+            )
+
+    def add_tools(self, tools: List[BaseTool]) -> None:
+        super().add_tools(tools)
+        self.update_agent_tools()
+        return
+
+    def run(self, instruction: str) -> AgentOutput:
+        assert (
+            self.agent is not None
+        ), "Lanchain AgentExecutor is not correclty initialized"
+
+        # Langchain AgentExecutor call
+        output = self.agent(instruction)["output"]
+
+        return AgentOutput(
+            text=output,
+            agent_type=self.agent_type,
+            status="finished",
+        )