Files
AIRegulation-DocAnalysis/backend/app/mcp/stats.py
T
wangweiandCopilot 31bbf80aeb feat: surface MCP server status in System Status page
Add per-tool in-memory call counters to the MCP module and a
GET /api/v1/status/mcp endpoint that joins them with the live tool
registry and endpoint config, then render it as a new card on the
System Status page with a one-click client-config copy button.

- app/mcp/stats.py: lock-guarded MCPStatsTracker (the mcp SDK runs sync
  tool bodies via anyio.to_thread.run_sync, so this is genuinely
  multi-threaded, unlike the async REST routes)
- app/mcp/server.py: instrument search_regulations, add get_mcp_status()
- app/config/settings.py: optional MCP_PUBLIC_URL override, required
  because the Vite proxy and reverse proxies rewrite the Host header
- StatusPage.tsx: MCP Server card, joins the existing parallel fetch

Counters are process-local by design; token usage is already persisted
by ModelUsageTracker since MCP calls route through ask().

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-08-03 11:37:22 +08:00

92 lines
3.4 KiB
Python

"""In-memory per-tool call counters for the MCP server.
Lives in `app/mcp/` rather than `app/shared/` because these counters are
meaningful only for the MCP transport: they answer "is anything actually
calling our MCP endpoint, and does it work?" for the System Status page.
Token consumption is deliberately not tracked here — MCP tool calls route
through AgentConversationService.ask() like every other caller, so the
existing ModelUsageTracker already accounts for it.
Counters are process-local and reset on restart. That is an accepted
tradeoff, recorded in the design spec: nothing billable depends on them.
"""
from __future__ import annotations
import threading
from dataclasses import dataclass
from datetime import datetime, timezone
from functools import lru_cache
from loguru import logger
@dataclass
class MCPToolStats:
"""Accumulated call outcomes for a single MCP tool."""
calls: int = 0
errors: int = 0
total_duration_ms: float = 0.0
last_called_at: datetime | None = None
@property
def avg_duration_ms(self) -> float | None:
"""Mean call duration, or None when the tool has never been called.
Returning None rather than 0.0 keeps "never called" distinguishable
from "called, but instantaneous" in the status UI.
"""
if self.calls == 0:
return None
return self.total_duration_ms / self.calls
class MCPStatsTracker:
"""Thread-safe registry of per-tool MCP call statistics.
The lock is load-bearing, not defensive habit: the mcp SDK dispatches
synchronous tool functions through anyio.to_thread.run_sync, so tool
bodies genuinely run on multiple worker threads at once — unlike the
async REST routes, which are serialized by the event loop.
"""
def __init__(self) -> None:
"""Initialize an empty registry guarded by a single lock."""
self._tools: dict[str, MCPToolStats] = {}
# One coarse lock is enough: record() runs once per MCP tool call and
# snapshot() is only read by the low-traffic status endpoint.
self._lock = threading.Lock()
def record(self, *, tool: str, duration_ms: float, success: bool) -> None:
"""Record the outcome of one MCP tool invocation.
Never raises: a defect in observability code must not turn a working
tool call into a protocol error for the client.
"""
try:
# Coerce outside the lock so a bad argument cannot abort mid-update
# and leave calls incremented but duration unaccounted for.
duration = float(duration_ms)
now = datetime.now(timezone.utc)
with self._lock:
stats = self._tools.setdefault(tool, MCPToolStats())
stats.calls += 1
if not success:
stats.errors += 1
stats.total_duration_ms += duration
stats.last_called_at = now
except Exception as exc: # noqa: BLE001 - tracking must never break a real call
logger.warning("MCPStatsTracker.record failed for tool {} - {}", tool, exc)
def snapshot(self) -> dict[str, MCPToolStats]:
"""Return a shallow copy of all tracked tools, safe to read outside the lock."""
with self._lock:
return dict(self._tools)
@lru_cache
def get_mcp_stats_tracker() -> MCPStatsTracker:
"""Return the process-wide singleton tracker (mirrors get_model_usage_tracker())."""
return MCPStatsTracker()