Files
DECNET/decnet/web/router/config/api_get_config.py
anti 255c2e5eb7 perf: cache auth user-lookup and admin list_users
The per-request SELECT users WHERE uuid=? in require_role was the
hidden tax behind every authed endpoint — it kept _execute at ~60%
across the profile even after the page caches landed. Even /health
(with its DB and Docker probes cached) was still 52% _execute from
this one query.

- dependencies.py: 10s TTL cache on get_user_by_uuid, well below JWT
  expiry. invalidate_user_cache(uuid) is called on password change,
  role change, and user delete.
- api_get_config.py: 5s TTL cache on the admin branch's list_users()
  (previously fetched every /config call). Invalidated on user
  create/update/delete.
- api_change_pass.py + api_manage_users.py: invalidation hooks on
  all user-mutating endpoints.
2026-04-17 19:56:39 -04:00

125 lines
3.8 KiB
Python

import asyncio
import time
from typing import Any, Optional
from fastapi import APIRouter, Depends
from decnet.env import DECNET_DEVELOPER
from decnet.telemetry import traced as _traced
from decnet.web.dependencies import require_viewer, repo
from decnet.web.db.models import UserResponse
router = APIRouter()
_DEFAULT_DEPLOYMENT_LIMIT = 10
_DEFAULT_MUTATION_INTERVAL = "30m"
# Cache config_limits / config_globals reads — these change on rare admin
# writes but get polled constantly by the UI and locust.
_STATE_TTL = 5.0
_state_cache: dict[str, tuple[Optional[dict[str, Any]], float]] = {}
_state_locks: dict[str, asyncio.Lock] = {}
# Admin branch fetched repo.list_users() on every /config call — cache 5s,
# invalidate on user create/update/delete so the admin UI stays consistent.
_USERS_TTL = 5.0
_users_cache: tuple[Optional[list[dict[str, Any]]], float] = (None, 0.0)
_users_lock: Optional[asyncio.Lock] = None
def _reset_state_cache() -> None:
"""Reset cached config state — used by tests."""
global _users_cache, _users_lock
_state_cache.clear()
# Drop any locks bound to the previous event loop — reusing one from
# a dead loop deadlocks the next test.
_state_locks.clear()
_users_cache = (None, 0.0)
_users_lock = None
def invalidate_list_users_cache() -> None:
global _users_cache
_users_cache = (None, 0.0)
async def _get_list_users_cached() -> list[dict[str, Any]]:
global _users_cache, _users_lock
value, ts = _users_cache
now = time.monotonic()
if value is not None and now - ts < _USERS_TTL:
return value
if _users_lock is None:
_users_lock = asyncio.Lock()
async with _users_lock:
value, ts = _users_cache
now = time.monotonic()
if value is not None and now - ts < _USERS_TTL:
return value
value = await repo.list_users()
_users_cache = (value, time.monotonic())
return value
async def _get_state_cached(name: str) -> Optional[dict[str, Any]]:
entry = _state_cache.get(name)
now = time.monotonic()
if entry is not None and now - entry[1] < _STATE_TTL:
return entry[0]
lock = _state_locks.setdefault(name, asyncio.Lock())
async with lock:
entry = _state_cache.get(name)
now = time.monotonic()
if entry is not None and now - entry[1] < _STATE_TTL:
return entry[0]
value = await repo.get_state(name)
_state_cache[name] = (value, time.monotonic())
return value
@router.get(
"/config",
tags=["Configuration"],
responses={
401: {"description": "Could not validate credentials"},
403: {"description": "Insufficient permissions"},
},
)
@_traced("api.get_config")
async def api_get_config(user: dict = Depends(require_viewer)) -> dict:
limits_state = await _get_state_cached("config_limits")
globals_state = await _get_state_cached("config_globals")
deployment_limit = (
limits_state.get("deployment_limit", _DEFAULT_DEPLOYMENT_LIMIT)
if limits_state
else _DEFAULT_DEPLOYMENT_LIMIT
)
global_mutation_interval = (
globals_state.get("global_mutation_interval", _DEFAULT_MUTATION_INTERVAL)
if globals_state
else _DEFAULT_MUTATION_INTERVAL
)
base = {
"role": user["role"],
"deployment_limit": deployment_limit,
"global_mutation_interval": global_mutation_interval,
}
if user["role"] == "admin":
all_users = await _get_list_users_cached()
base["users"] = [
UserResponse(
uuid=u["uuid"],
username=u["username"],
role=u["role"],
must_change_password=u["must_change_password"],
).model_dump()
for u in all_users
]
if DECNET_DEVELOPER:
base["developer_mode"] = True
return base