perf: QA Gatekeeper audit fixes for backend concurrency and thread-safety

backend/api/fashion_matches/router.py

@@ -269,7 +269,7 @@ def _get_colors_by_group(group: str, color_groups_map: dict, exclude: str | None
 
 
 @router.get("/{code}")
-async def get_fashion_matches(code: str):
+def get_fashion_matches(code: str):
     from worker.stylist_engine import StylistEngine
 
     engine = StylistEngine()
@@ -426,7 +426,7 @@ async def color_logic(req: ColorLogicRequest):
 
 
 @router.post("/outfit-suggest")
-async def outfit_suggest(req: OutfitSuggestRequest):
+def outfit_suggest(req: OutfitSuggestRequest):
     try:
         rules = _load_rules()
         color_keys = rules.get("color_keys", {})
@@ -531,7 +531,7 @@ class ScoreTestRequest(BaseModel):
 
 
 @router.post("/score-test")
-async def score_test(req: ScoreTestRequest):
+def score_test(req: ScoreTestRequest):
     try:
         from worker.stylist_engine import StylistEngine
 
@@ -569,7 +569,7 @@ async def score_test(req: ScoreTestRequest):
 
 
 @router.get("/audit/tag-coverage")
-async def audit_tag_coverage(limit: int = Query(300, ge=20, le=2000), q: str = ""):
+def audit_tag_coverage(limit: int = Query(300, ge=20, le=2000), q: str = ""):
     """Audit product tags vs rules coverage for data QA."""
     try:
         from worker.stylist_engine import StylistEngine
@@ -745,7 +745,7 @@ async def audit_tag_coverage(limit: int = Query(300, ge=20, le=2000), q: str = "
 
 # --- Rules Framework HTML View ---
 @router.get("/rules/view")
-async def rules_view():
+def rules_view():
     from collections import defaultdict
 
     from fastapi.responses import HTMLResponse

backend/common/starrocks_connection.py

@@ -6,6 +6,7 @@ Based on chatbot-rsa pattern
 import asyncio
 import logging
 import os
+import threading
 from typing import Any
 
 import aiomysql
@@ -47,8 +48,8 @@ get_db_connection = _manager.get_connection
 
 
 class StarRocksConnection:
-    # Shared connection (Singleton-like behavior) for all instances
-    _shared_conn = None
+    # Use thread-local storage to ensure thread-safety across FastAPI sync workers
+    _thread_local = threading.local()
 
     def __init__(
         self,
@@ -71,16 +72,17 @@ class StarRocksConnection:
         """
         Establish or reuse persistent connection.
         """
-        # 1. Try to reuse existing shared connection
-        if StarRocksConnection._shared_conn and StarRocksConnection._shared_conn.open:
+        # 1. Try to reuse existing thread-local connection
+        conn = getattr(StarRocksConnection._thread_local, 'conn', None)
+        if conn and conn.open:
             try:
                 # Ping to check if alive, reconnect if needed
-                StarRocksConnection._shared_conn.ping(reconnect=True)
-                self.conn = StarRocksConnection._shared_conn
+                conn.ping(reconnect=True)
+                self.conn = conn
                 return self.conn
             except Exception as e:
                 logger.warning(f"⚠️ Connection lost, reconnecting: {e}")
-                StarRocksConnection._shared_conn = None
+                StarRocksConnection._thread_local.conn = None
 
         # 2. Create new connection if needed
         print(f"   [DB] 🔌 Đang kết nối StarRocks (New Session): {self.host}:{self.port}...")
@@ -101,8 +103,8 @@ class StarRocksConnection:
             print("   [DB] ✅ Kết nối thành công.")
             logger.info("✅ Connected to StarRocks")
 
-            # Save to class variable
-            StarRocksConnection._shared_conn = new_conn
+            # Save to thread-local variable
+            StarRocksConnection._thread_local.conn = new_conn
             self.conn = new_conn
 
         except Exception as e:
@@ -136,7 +138,7 @@ class StarRocksConnection:
             print(f"   [DB] ❌ Lỗi truy vấn: {e!s}")
             logger.error(f"❌ StarRocks query error: {e}")
             # Incase of query error due to connection, invalidate it
-            StarRocksConnection._shared_conn = None
+            StarRocksConnection._thread_local.conn = None
             raise
         # FINALLY BLOCK REMOVED: Do NOT close connection
 
@@ -264,7 +266,8 @@ class StarRocksConnection:
 
     def close(self):
         """Explicitly close if needed (e.g. app shutdown)"""
-        if StarRocksConnection._shared_conn and StarRocksConnection._shared_conn.open:
-            StarRocksConnection._shared_conn.close()
-            StarRocksConnection._shared_conn = None
+        conn = getattr(StarRocksConnection._thread_local, 'conn', None)
+        if conn and conn.open:
+            conn.close()
+            StarRocksConnection._thread_local.conn = None
             self.conn = None