YueGuobin 6b73f00281 docs: update AI chat API design with detailed statistics collection
Update the AI chat API design documentation to provide comprehensive details about statistics collection during streaming conversations. The documentation now includes:

1. **Enhanced statistics collection logic**:
   - Clarified message_count increments for user messages, AI responses, and tool results
   - Added LLM call tracking via on_chat_model_start events
   - Detailed token counting methodology using LangGraph's usage_metadata

2. **Improved implementation details**:
   - Added specific event handlers for statistics collection
   - Explained LangGraph's cumulative token counting behavior
   - Provided real-world examples of token accumulation

3. **Updated data models**:
   - Enhanced ChatSession model documentation with field descriptions
   - Separated fields into categories (basic, statistics, timestamps, reserved)

4. **Refined architecture documentation**:
   - Added detailed flow for stream_chat method
   - Documented statistics collection mechanism during SSE streaming
   - Explained batch update strategy to reduce database writes

The changes ensure developers understand how conversation statistics are collected, processed, and stored without impacting streaming performance.
2026-03-04 22:33:28 +08:00

511 lines
19 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 json
import logging
import os
from datetime import datetime
from typing import AsyncGenerator, Dict, Any, Optional, List
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
from gns3server.agent.gns3_copilot.chat_sessions_repository import ChatSessionsRepository
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()
# Create chat_sessions table in the same database
await self._create_chat_sessions_table(conn)
self._checkpointer_path = checkpointer_path
self._initialized = True
log.info("Project checkpointer created at: %s", checkpointer_path)
return self._checkpointer
async def _create_chat_sessions_table(self, conn: aiosqlite.Connection):
"""
Create the chat_sessions table in the checkpoint database.
Args:
conn: aiosqlite connection
"""
await conn.execute("""
CREATE TABLE IF NOT EXISTS chat_sessions (
id INTEGER PRIMARY KEY AUTOINCREMENT,
thread_id TEXT UNIQUE NOT NULL,
user_id TEXT NOT NULL,
project_id TEXT NOT NULL,
title TEXT DEFAULT 'New Conversation',
-- Statistics
message_count INTEGER DEFAULT 0,
llm_calls_count INTEGER DEFAULT 0,
input_tokens INTEGER DEFAULT 0,
output_tokens INTEGER DEFAULT 0,
total_tokens INTEGER DEFAULT 0,
-- Timestamps
last_message_at TIMESTAMP,
created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
-- Reserved fields (JSON strings)
metadata TEXT DEFAULT '{}',
stats TEXT DEFAULT '{}'
)
""")
# Create indexes
await conn.execute("CREATE INDEX IF NOT EXISTS idx_thread_id ON chat_sessions(thread_id)")
await conn.execute("CREATE INDEX IF NOT EXISTS idx_user_project ON chat_sessions(user_id, project_id)")
await conn.commit()
log.debug("chat_sessions table created in checkpoint database")
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
"""
log.info(
"Stream chat started: project_id=%s, user_id=%s, session_id=%s, mode=%s",
project_id,
user_id,
session_id,
mode,
)
# Ensure checkpointer is initialized
if not self._checkpointer_conn:
await self._get_checkpointer()
# Get or create chat session
repo = ChatSessionsRepository(self._checkpointer_conn)
session = await repo.get_session_by_thread(session_id)
is_new_session = session is None
if is_new_session:
# Create new session
session = await repo.create_session(
thread_id=session_id,
user_id=user_id or "",
project_id=project_id or "",
title="New Conversation"
)
log.debug("Created new chat session: thread_id=%s", session_id)
# 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)
log.debug("JWT token set in context")
if llm_config:
from gns3server.agent.gns3_copilot.gns3_client import set_current_llm_config
set_current_llm_config(llm_config)
log.debug("LLM config set in context: provider=%s, model=%s",
llm_config.get("provider"), llm_config.get("model"))
# Build config - only thread-safe identifiers
config = {
"configurable": {
"thread_id": session_id,
"project_id": project_id,
},
"metadata": {
"user_id": user_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()
log.debug("LangGraph graph obtained, starting stream")
# Track statistics for session update
message_count = 1 # User message
llm_calls_count = 0
input_tokens = 0
output_tokens = 0
last_message_at = datetime.utcnow().isoformat()
# Track if we've counted the AI response for this turn
ai_response_counted = False
tool_messages_counted = 0
# Stream events
try:
async for event in graph.astream_events(inputs, config=config, version="v2"):
event_type = event.get("event", "")
data = event.get("data", {})
# Track LLM calls and tokens
if event_type == "on_chat_model_start":
llm_calls_count += 1
log.debug("LLM call started, count=%d", llm_calls_count)
elif event_type == "on_chat_model_end":
# Extract token usage from response metadata
# Try multiple possible locations where token usage might be stored
token_info_found = False
# Method 1: response.usage_metadata
response = data.get("response", {})
if hasattr(response, "usage_metadata"):
usage = response.usage_metadata
if usage:
input_tokens += usage.get("input_tokens", 0)
output_tokens += usage.get("output_tokens", 0)
token_info_found = True
# Method 2: output.usage_metadata
if not token_info_found:
output_msg = data.get("output", {})
if hasattr(output_msg, "usage_metadata"):
usage = output_msg.usage_metadata
if usage:
input_tokens += usage.get("input_tokens", 0)
output_tokens += usage.get("output_tokens", 0)
token_info_found = True
# Method 3: Check data directly for token usage fields
if not token_info_found:
if "input_tokens" in data:
input_tokens += data.get("input_tokens", 0)
if "output_tokens" in data:
output_tokens += data.get("output_tokens", 0)
if "input_tokens" in data or "output_tokens" in data:
token_info_found = True
# Count AI response as one message (only once per turn)
if not ai_response_counted:
message_count += 1
ai_response_counted = True
# Track tool messages
elif event_type == "on_tool_end":
message_count += 1 # Tool result message
tool_messages_counted += 1
log.debug("Tool message counted, message_count=%d", message_count)
# Convert event to chunk for SSE streaming
chunk = self._convert_event_to_chunk(event, session_id)
if chunk:
log.debug("Yielding chunk: type=%s", chunk.get("type"))
yield chunk
# Update session statistics after successful stream
await repo.update_session(
thread_id=session_id,
message_count=message_count,
llm_calls_count=llm_calls_count,
input_tokens=input_tokens,
output_tokens=output_tokens,
total_tokens=input_tokens + output_tokens,
last_message_at=last_message_at
)
log.info("Session statistics updated: thread_id=%s, messages=%d, llm_calls=%d, tokens=%d+%d=%d",
session_id, message_count, llm_calls_count, input_tokens, output_tokens, input_tokens + output_tokens)
# Sync auto-generated title from checkpoint state
final_state = await graph.aget_state(config)
if final_state and "conversation_title" in final_state.values:
generated_title = final_state.values["conversation_title"]
current_session = await repo.get_session_by_thread(session_id)
if current_session and current_session.title != generated_title:
await repo.update_session(thread_id=session_id, title=generated_title)
log.info("Auto-generated title synced: thread_id=%s, title=%s",
session_id, generated_title)
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 list_sessions(self, user_id: Optional[str] = None, limit: int = 100) -> List[Dict[str, Any]]:
"""
List chat sessions for this project.
Args:
user_id: Filter by user ID (optional)
limit: Maximum number of sessions to return
Returns:
List of session dictionaries
"""
if not self._checkpointer_conn:
await self._get_checkpointer()
repo = ChatSessionsRepository(self._checkpointer_conn)
sessions = await repo.list_sessions(user_id=user_id, limit=limit)
return [s.to_dict() for s in sessions]
async def delete_session(self, session_id: str) -> bool:
"""
Delete a chat session and its checkpoints.
Args:
session_id: Thread ID to delete
Returns:
True if deleted, False if not found
"""
if not self._checkpointer_conn:
await self._get_checkpointer()
repo = ChatSessionsRepository(self._checkpointer_conn)
return await repo.delete_session(session_id)
async def rename_session(self, session_id: str, new_title: str) -> Optional[Dict[str, Any]]:
"""
Rename a chat session.
Args:
session_id: Thread ID
new_title: New title
Returns:
Updated session dictionary or None
"""
if not self._checkpointer_conn:
await self._get_checkpointer()
repo = ChatSessionsRepository(self._checkpointer_conn)
session = await repo.update_session(thread_id=session_id, title=new_title)
return session.to_dict() if session else None
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