Improve feedback API resilience

app.py

@@ -1,8 +1,13 @@
+import logging
 import os
+import threading
 import time
 from urllib.error import URLError, HTTPError
+
 import requests
 from flask import Flask, render_template, jsonify, request, Blueprint
+from requests.adapters import HTTPAdapter
+from urllib3.util.retry import Retry
 from werkzeug.middleware.proxy_fix import ProxyFix
 
 app = Flask(__name__)
@@ -13,6 +18,10 @@ DISCORD_WEBHOOK_URL = os.getenv("DISCORD_WEBHOOK_URL")
 
 COOLDOWN_SECONDS = 60 * 60
 _last_feedback_by_ip = {}
+_feedback_lock = threading.Lock()
+
+logging.basicConfig(level=os.getenv("LOG_LEVEL", "INFO"))
+logger = logging.getLogger(__name__)
 
 PROHIBITED_WORDS = {
     'fuck', 'shit', 'asshole', 'bitch', 'bastard', 'damn', 'crap', 'dick', 'piss', 'cunt',
@@ -39,6 +48,21 @@ def _contains_prohibited_word(text: str) -> bool:
     return any(w in lower for w in PROHIBITED_WORDS)
 
 
+def _get_discord_session() -> requests.Session:
+    session = requests.Session()
+    retry = Retry(
+        total=3,
+        backoff_factor=0.5,
+        status_forcelist=(429, 500, 502, 503, 504),
+        allowed_methods=("POST",),
+        raise_on_status=False,
+    )
+    adapter = HTTPAdapter(max_retries=retry)
+    session.mount("https://", adapter)
+    session.mount("http://", adapter)
+    return session
+
+
 def _post_to_discord(payload: dict) -> None:
     if not DISCORD_WEBHOOK_URL:
         raise RuntimeError("DISCORD_WEBHOOK_URL is not set on the server.")
@@ -52,16 +76,26 @@ def _post_to_discord(payload: dict) -> None:
         "Accept": "application/json",
     }
 
-    resp = requests.post(url, json=payload, headers=headers, timeout=10)
+    session = _get_discord_session()
+    resp = session.post(url, json=payload, headers=headers, timeout=10)
     if resp.status_code not in (200, 204):
         raise RuntimeError(f"Discord returned {resp.status_code}: {resp.text[:500]}")
 
 
+def _prune_feedback_cache(now: float) -> None:
+    stale_cutoff = now - COOLDOWN_SECONDS
+    stale_ips = [ip for ip, ts in _last_feedback_by_ip.items() if ts < stale_cutoff]
+    for ip in stale_ips:
+        _last_feedback_by_ip.pop(ip, None)
+
+
 @api.post("/feedback")
 def api_feedback():
     ip = _get_client_ip()
     now = time.time()
-    last = _last_feedback_by_ip.get(ip, 0)
+    with _feedback_lock:
+        _prune_feedback_cache(now)
+        last = _last_feedback_by_ip.get(ip, 0)
 
     if now - last < COOLDOWN_SECONDS:
         retry_after = int(COOLDOWN_SECONDS - (now - last))
@@ -98,9 +132,11 @@ def api_feedback():
     try:
         _post_to_discord({"username": name, "content": content})
     except (HTTPError, URLError, RuntimeError) as e:
+        logger.exception("Failed to forward feedback to Discord")
         return jsonify({"ok": False, "error": f"Failed to forward feedback: {str(e)}"}), 502
 
-    _last_feedback_by_ip[ip] = now
+    with _feedback_lock:
+        _last_feedback_by_ip[ip] = now
     return jsonify({"ok": True}), 200