YueGuobin 289ae0cddf feat(agent): remove redundant done message from stream_chat
The `stream_chat` method was yielding a "done" message after streaming all chunks, but this is unnecessary as the streaming completion is already indicated by the end of the stream. Removing this redundant message simplifies the response handling and aligns with typical streaming patterns.
2026-03-04 13:57:03 +08:00

294 lines
10 KiB
Python

"""
GNS3 Copilot Agent Service
Provides project-level Agent instances with SQLite checkpoint management.
Each project has its own AgentService with a dedicated checkpoint database
in the project directory.
"""
import asyncio
import logging
import os
from typing import AsyncGenerator, Dict, Any, Optional
from uuid import uuid4
import aiosqlite
from langchain_core.messages import HumanMessage, AIMessage, ToolMessage
from langgraph.checkpoint.sqlite.aio import AsyncSqliteSaver
from gns3server.agent.gns3_copilot.agent.gns3_copilot import agent_builder
log = logging.getLogger(__name__)
class AgentService:
"""
Project-level Agent Service with async checkpoint management.
Manages a LangGraph agent instance with SQLite-based state persistence
for a single GNS3 project.
"""
def __init__(self, project_path: str):
"""
Initialize AgentService for a project.
Args:
project_path: Path to the GNS3 project directory
"""
self.project_path = project_path
self._checkpointer: Optional[AsyncSqliteSaver] = None
self._checkpointer_conn: Optional[aiosqlite.Connection] = None
self._checkpointer_path: Optional[str] = None
self._graph = None
self._init_lock = asyncio.Lock()
self._initialized = False
def _get_checkpoint_dir(self) -> str:
"""Get or create the checkpoint directory for this project."""
checkpoint_dir = os.path.join(self.project_path, "gns3-copilot")
os.makedirs(checkpoint_dir, exist_ok=True)
return checkpoint_dir
async def _get_checkpointer(self) -> AsyncSqliteSaver:
"""
Get or create the SQLite checkpointer for this project.
Returns:
AsyncSqliteSaver instance
"""
async with self._init_lock:
if self._checkpointer is not None:
return self._checkpointer
checkpoint_dir = self._get_checkpoint_dir()
checkpointer_path = os.path.join(checkpoint_dir, "copilot_checkpoints.db")
log.debug("Creating checkpointer at: %s", checkpointer_path)
# Close existing connection if switching projects
if self._checkpointer_conn:
try:
await self._checkpointer_conn.close()
log.debug("Closed previous checkpointer connection")
except Exception as e:
log.warning("Error closing old checkpointer connection: %s", e)
# Create new connection
conn = await aiosqlite.connect(checkpointer_path)
# Enable WAL mode for better concurrent performance
await conn.execute("PRAGMA journal_mode=WAL;")
self._checkpointer_conn = conn # Save connection reference to prevent GC
self._checkpointer = AsyncSqliteSaver(conn)
# CRITICAL: Initialize database schema
await self._checkpointer.setup()
self._checkpointer_path = checkpointer_path
self._initialized = True
log.info("Project checkpointer created at: %s", checkpointer_path)
return self._checkpointer
async def _get_graph(self):
"""Get or compile the LangGraph agent."""
if self._graph is None:
checkpointer = await self._get_checkpointer()
self._graph = agent_builder.compile(checkpointer=checkpointer)
log.info("LangGraph agent compiled for project: %s", self.project_path)
return self._graph
async def stream_chat(
self,
message: str,
session_id: str,
project_id: Optional[str] = None,
user_id: Optional[str] = None,
jwt_token: Optional[str] = None,
mode: str = "text",
llm_config: Optional[Dict[str, Any]] = None
) -> AsyncGenerator[Dict[str, Any], None]:
"""
Stream chat responses from the agent.
Args:
message: User message
session_id: Session/thread ID for conversation continuity
project_id: GNS3 project ID (optional, for context)
user_id: User ID for metadata tracking
jwt_token: JWT token for API authentication (optional)
mode: Interaction mode (default: "text")
llm_config: LLM configuration dict (provider, model, api_key, etc.)
Yields:
Dict containing SSE-compatible response chunks
"""
# Set request-scoped context variables (memory-only, not persisted)
if jwt_token:
from gns3server.agent.gns3_copilot.gns3_client import set_current_jwt_token
set_current_jwt_token(jwt_token)
if llm_config:
from gns3server.agent.gns3_copilot.gns3_client import set_current_llm_config
set_current_llm_config(llm_config)
# Build config - only thread-safe identifiers
config = {
"configurable": {
"thread_id": session_id,
},
"metadata": {
"user_id": user_id,
"project_id": project_id,
}
}
# Build inputs
inputs = {
"messages": [HumanMessage(content=message)],
"llm_calls": 0,
"remaining_steps": 20,
"mode": mode,
}
# Get the compiled graph
graph = await self._get_graph()
# Stream events
try:
async for event in graph.astream_events(inputs, config=config, version="v2"):
chunk = self._convert_event_to_chunk(event, session_id)
if chunk:
yield chunk
except Exception as e:
log.error("Error in stream_chat: %s", e, exc_info=True)
yield {"type": "error", "error": str(e), "session_id": session_id}
def _convert_event_to_chunk(self, event: Dict[str, Any], session_id: str) -> Optional[Dict[str, Any]]:
"""
Convert LangGraph event to API response chunk.
Args:
event: LangGraph event from astream_events
session_id: Session ID for the response
Returns:
Dict for SSE response or None if event should be filtered
"""
event_type = event.get("event", "")
data = event.get("data", {})
if event_type == "on_chat_model_stream":
# Streaming text content from LLM
chunk = data.get("chunk", {})
# chunk is AIMessageChunk object, access content directly
content = getattr(chunk, "content", "")
if content:
return {"type": "content", "content": content}
elif event_type == "on_tool_start":
# Tool execution started
return {
"type": "tool_start",
"tool_name": event.get("name", ""),
"session_id": session_id
}
elif event_type == "on_tool_end":
# Tool execution completed
output = data.get("output", "")
# Convert output to string if it's not already
if not isinstance(output, str):
output = str(output)
return {
"type": "tool_end",
"tool_name": event.get("name", ""),
"tool_output": output,
"session_id": session_id
}
return None
async def get_history(self, session_id: str, limit: int = 100) -> Dict[str, Any]:
"""
Get conversation history for a session.
Args:
session_id: Session/thread ID
limit: Maximum number of messages to retrieve
Returns:
Dict containing thread_id, title, and messages
"""
config = {"configurable": {"thread_id": session_id}}
try:
graph = await self._get_graph()
state = await graph.aget_state(config)
if state and "messages" in state.values:
messages = []
for msg in state.values["messages"][-limit:]:
messages.append(self._convert_message_to_dict(msg))
title = state.values.get("conversation_title", "New Conversation")
return {
"thread_id": session_id,
"title": title,
"messages": messages
}
except Exception as e:
log.error("Error getting history: %s", e, exc_info=True)
return {
"thread_id": session_id,
"title": "New Conversation",
"messages": []
}
def _convert_message_to_dict(self, msg) -> Dict[str, Any]:
"""Convert a LangChain message to dict format."""
from datetime import datetime
msg_type = type(msg).__name__
result = {
"id": getattr(msg, "id", str(uuid4())),
"role": "user",
"content": getattr(msg, "content", str(msg)),
"created_at": datetime.utcnow().isoformat() + "Z",
}
if msg_type == "HumanMessage":
result["role"] = "user"
elif msg_type == "AIMessage":
result["role"] = "assistant"
if hasattr(msg, "tool_calls") and msg.tool_calls:
result["tool_calls"] = msg.tool_calls
elif msg_type == "ToolMessage":
result["role"] = "tool"
result["tool_call_id"] = getattr(msg, "tool_call_id", None)
result["name"] = getattr(msg, "name", None)
elif msg_type == "SystemMessage":
result["role"] = "system"
return result
async def close(self):
"""
Close the checkpointer connection and cleanup resources.
"""
async with self._init_lock:
if self._checkpointer_conn:
try:
await self._checkpointer_conn.close()
log.debug("Checkpointer connection closed for: %s", self.project_path)
except Exception as e:
log.warning("Error closing checkpointer connection: %s", e)
finally:
self._checkpointer_conn = None
self._checkpointer = None
self._graph = None
self._initialized = False