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FabledScribe/src/scribe/app.py
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bvandeusenandClaude Opus 5 1fcfd47ab6
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fix(startup): a slow database costs seconds, not the instance (#4181)
On 2026-09-19 a host storage stall made one Postgres checkpoint of 14
buffers take 281 seconds against a 1.3-second baseline. The app restarted
into the tail of it, `get_maintenance_hour()` — the first DB read in
`before_serving` — hung with no deadline, Hypercorn killed the worker at
its 60-second lifespan timeout, and nothing retries a failed lifespan. A
five-minute disk hiccup became a three-hour outage that only a human
restart could clear. Every MCP call returned 405, which reads like a
routing fault and was nothing of the kind: nothing was serving.

Three changes, none of which prevent a stall — they stop a transient one
becoming a permanent one.

1. THE STARTUP READ IS BOUNDED (rule 156). `get_maintenance_hour` already
   answered `_DEFAULT_HOUR` for a value it could not parse; a database
   that will not answer in three seconds is the same class of "no usable
   value here". The failure is now a WARNING naming the symptom — the
   breadcrumb whose absence meant this was only diagnosable from
   Postgres's own log — and a default run-hour, instead of the app.

2. THE BACKFILL NO LONGER RACES STARTUP. Its comment said it "never
   blocks the server from accepting requests": true of requests, false of
   startup, because the task began while `before_serving` was still
   running and competed for the same pool. Both of the incident's
   cancelled statements were in flight together. It now waits on a flag
   released on the hook's way out — in a `finally`, never after the work
   (rule 157), because an undeadlined wait is only safe when the wake-up
   cannot be missed.

3. THE ENGINE CANNOT WAIT FOREVER TO CONNECT. asyncpg's default is 60s,
   the whole lifespan budget spent before a query is sent. `command_timeout`
   is deliberately NOT set alongside it and the comment says why: it would
   apply to every statement, and this app runs long ones on purpose.

tests/test_startup_survives_a_slow_database.py asserts the shape rather
than the stall: a read that never returns still yields an hour, the
warning names the symptom, a healthy read is unaffected, the backfill
does no work before release, the flag is released even when startup
raises, and the engine's connect args carry a deadline but no blanket
statement timeout.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01821k5B3Ysecp9fNYs92Kuy
2026-09-19 10:50:57 -04:00

363 lines
16 KiB
Python

import logging
import time
import traceback as tb_module
from pathlib import Path
from quart import Quart, g, jsonify, make_response, request, send_from_directory
from scribe.config import Config
from scribe.routes.admin import admin_bp
from scribe.routes.api import api
from scribe.routes.auth import auth_bp
from scribe.routes.export import export_bp
from scribe.routes.notes import notes_bp
from scribe.routes.milestones import milestones_bp
from scribe.routes.task_logs import task_logs_bp
from scribe.routes.projects import projects_bp
from scribe.routes.retrieval import retrieval_bp
from scribe.routes.settings import settings_bp
from scribe.routes.tasks import tasks_bp
from scribe.routes.groups import groups_bp
from scribe.routes.shares import shares_bp
from scribe.routes.in_app_notifications import notifications_bp
from scribe.routes.users import users_bp
from scribe.routes.api_keys import api_keys_bp
from scribe.routes.search import search_bp
from scribe.routes.profile import profile_bp
from scribe.routes.knowledge import knowledge_bp
from scribe.routes.rulebooks import rulebooks_bp
from scribe.routes.plugin import plugin_bp
from scribe.routes.design_systems import design_systems_bp
from scribe.routes.trash import trash_bp
from scribe.routes.dashboard import dashboard_bp
from scribe.routes.systems import systems_bp
from scribe.routes.canonical_systems import canonical_systems_bp
from scribe.routes.snippets import snippets_bp
from scribe.routes.webhooks import webhooks_bp
from scribe.mcp import mount_mcp
STATIC_DIR = Path(__file__).parent / "static"
logger = logging.getLogger(__name__)
def create_app() -> Quart:
# Configure logging
logging.basicConfig(
format="%(asctime)s [%(levelname)s] %(name)s: %(message)s",
level=getattr(logging, Config.LOG_LEVEL.upper(), logging.INFO),
)
# Validate config early so misconfigurations surface immediately with clear messages
try:
Config.validate()
except ValueError as exc:
logging.getLogger(__name__).error("Invalid configuration:\n%s", exc)
raise
app = Quart(__name__, static_folder=None)
app.secret_key = Config.SECRET_KEY
app.config["SESSION_COOKIE_HTTPONLY"] = True
app.config["SESSION_COOKIE_SAMESITE"] = "Lax"
app.config["SESSION_COOKIE_SECURE"] = Config.SECURE_COOKIES
if Config.SECRET_KEY == "dev-secret-change-me":
logger.warning(
"SECRET_KEY is set to the default value — session cookies are insecure. "
"Set SECRET_KEY or SECRET_KEY_FILE for production use."
)
if not Config.TRUST_PROXY_HEADERS:
logger.warning(
"TRUST_PROXY_HEADERS is not set. If this instance is behind a reverse proxy "
"(nginx, Caddy, Traefik) set TRUST_PROXY_HEADERS=true so rate limiting uses "
"real client IPs rather than the proxy IP."
)
app.register_blueprint(admin_bp)
app.register_blueprint(api)
app.register_blueprint(auth_bp)
app.register_blueprint(export_bp)
app.register_blueprint(milestones_bp)
app.register_blueprint(notes_bp)
app.register_blueprint(projects_bp)
app.register_blueprint(retrieval_bp)
app.register_blueprint(settings_bp)
app.register_blueprint(task_logs_bp)
app.register_blueprint(tasks_bp)
app.register_blueprint(groups_bp)
app.register_blueprint(shares_bp)
app.register_blueprint(notifications_bp)
app.register_blueprint(users_bp)
app.register_blueprint(api_keys_bp)
app.register_blueprint(search_bp)
app.register_blueprint(profile_bp)
app.register_blueprint(knowledge_bp)
app.register_blueprint(rulebooks_bp)
app.register_blueprint(plugin_bp)
app.register_blueprint(design_systems_bp)
app.register_blueprint(trash_bp)
app.register_blueprint(dashboard_bp)
app.register_blueprint(systems_bp)
app.register_blueprint(canonical_systems_bp)
app.register_blueprint(snippets_bp)
app.register_blueprint(webhooks_bp)
@app.before_request
async def before_request():
g.request_start = time.monotonic()
@app.after_request
async def after_request(response):
duration = time.monotonic() - getattr(g, "request_start", time.monotonic())
duration_ms = round(duration * 1000, 1)
# Downgrade noisy high-frequency / static paths to DEBUG
_quiet = (
request.path in {"/api/health", "/api/chat/status"}
or request.path.startswith(("/static/", "/assets/", "/sw.js", "/manifest.json"))
)
log_fn = logger.debug if _quiet else logger.info
log_fn(
"%s %s %s %.1fms",
request.method,
request.path,
response.status_code,
duration_ms,
)
# Log usage for API requests (skip logs endpoint to avoid recursion)
if request.path.startswith("/api/") and not request.path.startswith("/api/admin/logs"):
try:
from scribe.services.logging import log_usage
user = getattr(g, "user", None)
await log_usage(
user_id=user.id if user else None,
username=user.username if user else None,
endpoint=request.path,
method=request.method,
status_code=response.status_code,
duration_ms=duration_ms,
)
except Exception:
logger.debug("Failed to log usage", exc_info=True)
response.headers.setdefault("X-Content-Type-Options", "nosniff")
response.headers.setdefault("X-Frame-Options", "DENY")
response.headers.setdefault("Referrer-Policy", "strict-origin-when-cross-origin")
response.headers.setdefault(
"Content-Security-Policy",
"default-src 'self'; "
"script-src 'self' 'unsafe-inline' 'wasm-unsafe-eval'; "
"style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; "
"img-src 'self' data: blob:; "
"connect-src 'self'; "
"font-src 'self' data: https://fonts.gstatic.com; "
"object-src 'none'; "
"base-uri 'self'; worker-src 'self' blob:;"
)
return response
@app.before_serving
async def startup():
import asyncio
# Set on the last line of this hook; the deferred backfill below waits
# on it. An Event rather than a bare bool so the waiter is woken
# instead of polling, and declared here — inside the hook, where
# `asyncio` is in scope and a running loop exists — rather than in
# `create_app`, which runs before either is true.
_startup_finished = asyncio.Event()
from scribe.services.auth import start_auth_token_retention_loop
from scribe.services.embeddings import (
backfill_milestone_embeddings, backfill_note_embeddings, backfill_rule_embeddings,
)
from scribe.services.logging import start_log_retention_loop
from scribe.services.notifications import start_notification_loop
start_log_retention_loop()
start_notification_loop()
start_auth_token_retention_loop()
# Backfill embeddings for any notes that don't have one. Runs in the
# background so it never blocks the server from accepting requests —
# and, since #4181, not until the rest of this hook has finished.
#
# "Background" was true of REQUESTS and false of STARTUP. A task
# created here begins immediately, while `before_serving` is still
# running, so its four passes competed with the startup hook's own
# database reads for the same connection pool. That is survivable on a
# healthy disk and fatal on a sick one: on 2026-09-19 both this
# backfill's first query and the hook's maintenance-hour read were
# cancelled together when Hypercorn killed the worker at its lifespan
# timeout, and the instance stayed down for three hours.
#
# The wait is on the SERVING FLAG rather than a sleep, because a sleep
# would be a guess about how long the rest of the hook takes and would
# be wrong in exactly the conditions that matter.
async def _delayed_backfill() -> None:
await _startup_finished.wait()
try:
await backfill_note_embeddings()
except Exception:
logger.warning("Embedding backfill failed", exc_info=True)
# Rules got vectors in milestone 307; every rule written before it
# has none, so this is the pass that makes them findable at all.
try:
await backfill_rule_embeddings()
except Exception:
logger.warning("Rule embedding backfill failed", exc_info=True)
# Milestones got vectors in milestone 415, so a plan written before
# it is findable only after this pass.
try:
await backfill_milestone_embeddings()
except Exception:
logger.warning("Milestone embedding backfill failed", exc_info=True)
# Snippets written before migration 0070 have no `notes.data` mirror,
# and the location reverse lookup queries that column — an unfilled
# row would read as "no snippet here" rather than as a gap. Separate
# try block so neither backfill can skip the other.
try:
from scribe.services.snippets import backfill_snippet_data
await backfill_snippet_data()
except Exception:
logger.warning("Snippet data backfill failed", exc_info=True)
# Created here but gated on the flag released at the END of this hook,
# so the task exists (nothing can forget to start it) while none of its
# work overlaps startup's own.
asyncio.create_task(_delayed_backfill())
# RELEASED IN A `finally`, never after the work (rules 156 and 157).
# The waiter above has no deadline of its own, and the way to make an
# undeadlined wait safe is to make the release unmissable: if anything
# below raises, the flag is still set and the task ends instead of
# living on as a coroutine nobody will ever wake.
try:
# Recurrence scheduler (recurring-task spawn every 15m)
from scribe.services.recurrence_scheduler import start_recurrence_scheduler
start_recurrence_scheduler(asyncio.get_running_loop())
# Version-pinning scheduler (daily auto-pin scan at 03:00 UTC)
from scribe.services.version_pinning_scheduler import (
start_version_pinning_scheduler,
)
start_version_pinning_scheduler(asyncio.get_running_loop())
# Trash retention scheduler (daily expired-trash purge at 03:30 UTC)
from scribe.services.trash_scheduler import start_trash_scheduler
start_trash_scheduler(asyncio.get_running_loop())
# DB maintenance scheduler (daily targeted VACUUM ANALYZE, default
# 04:00 UTC). `get_maintenance_hour` is the FIRST database read in
# this hook and is bounded for that reason (#4181) — see the long
# comment above `_STARTUP_READ_TIMEOUT`. Anything added here that
# touches the database needs the same treatment: a lifespan hook
# that does not return is a worker that never serves.
from scribe.services.db_maintenance_scheduler import (
get_maintenance_hour,
start_db_maintenance_scheduler,
)
start_db_maintenance_scheduler(
asyncio.get_running_loop(), await get_maintenance_hour()
)
# Diagnostic instrumentation — heartbeat, signal handlers, asyncio
# exception hook. Cheap (~1 log line/min), high diagnostic value when
# the app crashes mysteriously. See services/diagnostics.py.
from scribe.services.diagnostics import start_diagnostics
start_diagnostics(asyncio.get_running_loop())
finally:
# STARTUP IS OVER — release the backfill (#4181). Everything above
# is work the server needs done before it serves; everything the
# backfill does is work that can wait for a server already up.
logger.info("Startup complete; releasing deferred backfill")
_startup_finished.set()
@app.after_serving
async def shutdown():
from scribe.services.recurrence_scheduler import stop_recurrence_scheduler
stop_recurrence_scheduler()
from scribe.services.version_pinning_scheduler import (
stop_version_pinning_scheduler,
)
stop_version_pinning_scheduler()
from scribe.services.trash_scheduler import stop_trash_scheduler
stop_trash_scheduler()
from scribe.services.db_maintenance_scheduler import (
stop_db_maintenance_scheduler,
)
stop_db_maintenance_scheduler()
from scribe.services.diagnostics import stop_diagnostics
stop_diagnostics()
@app.route("/")
async def serve_index():
resp = await make_response(
await send_from_directory(STATIC_DIR, "index.html")
)
resp.headers["Cache-Control"] = "no-cache, no-store, must-revalidate"
return resp
# File extensions that belong to the SPA or its assets.
# Anything else with an extension is not a valid app path and gets a hard 404.
_SPA_EXTENSIONS = {
"", ".html", ".js", ".css", ".ico", ".png", ".jpg", ".jpeg",
".svg", ".webp", ".woff", ".woff2", ".ttf", ".otf", ".map", ".json",
}
@app.errorhandler(404)
async def handle_404(error):
# Return JSON 404 for API routes
if request.path.startswith("/api/"):
return jsonify({"error": "Not found"}), 404
# Try to serve a real static file first
path = request.path.lstrip("/")
file_path = STATIC_DIR / path
if path and file_path.is_file():
return await send_from_directory(STATIC_DIR, path)
# Reject paths with file extensions the app doesn't serve.
# This turns scanner probes (.php, .asp, .cgi, etc.) into honest 404s
# instead of serving them the Vue SPA with a misleading 200.
from pathlib import PurePosixPath
suffix = PurePosixPath(request.path).suffix.lower()
if suffix not in _SPA_EXTENSIONS:
return "", 404
# SPA fallback for clean client-side routes (/notes/123, /chat, etc.)
resp = await make_response(
await send_from_directory(STATIC_DIR, "index.html")
)
resp.headers["Cache-Control"] = "no-cache, no-store, must-revalidate"
return resp
@app.errorhandler(500)
async def handle_500(error):
logger.exception("Internal server error on %s %s", request.method, request.path)
try:
from scribe.services.logging import log_error
user = getattr(g, "user", None)
await log_error(
user_id=user.id if user else None,
username=user.username if user else None,
endpoint=request.path,
method=request.method,
error_type=type(error).__name__,
error_message=str(error),
traceback=tb_module.format_exc(),
)
except Exception:
logger.debug("Failed to log error", exc_info=True)
if request.path.startswith("/api/"):
return jsonify({"error": "Internal server error"}), 500
return "Internal Server Error", 500
mount_mcp(app)
return app