Replace streaming endpoint local cache with shared DB cache

backend/api/content_planning/api/content_strategy/endpoints/streaming_endpoints.py

@@ -12,11 +12,12 @@ from loguru import logger
 import json
 import asyncio
 from datetime import datetime
-from collections import defaultdict
-import time
+from datetime import timedelta
 
 # Import database
 from services.database import get_db_session
+from models.content_strategy_state_models import StreamingCacheState
+from models.enhanced_strategy_models import Base
 
 # Import authentication middleware
 from middleware.auth_middleware import get_current_user, get_current_user_with_query_token
@@ -32,28 +33,100 @@ from ....utils.constants import ERROR_MESSAGES, SUCCESS_MESSAGES
 
 router = APIRouter(tags=["Strategy Streaming"])
 
-# Cache for streaming endpoints (5 minutes cache)
-streaming_cache = defaultdict(dict)
-CACHE_DURATION = 300  # 5 minutes
+STREAMING_CACHE_TTL_SECONDS = 300
+STREAMING_CACHE_MAX_KEYS_PER_USER = 20
+STREAMING_CACHE_ENDPOINT_VERSION = "v1"
 
-def get_cached_data(cache_key: str) -> Optional[Dict[str, Any]]:
-    """Get cached data if it exists and is not expired."""
-    if cache_key in streaming_cache:
-        cached_data = streaming_cache[cache_key]
-        if time.time() - cached_data.get("timestamp", 0) < CACHE_DURATION:
-            return cached_data.get("data")
+
+def _build_cache_key(endpoint_name: str, authenticated_user_id: str) -> str:
+    """Build namespaced cache key by endpoint version and user."""
+    return f"streaming:{STREAMING_CACHE_ENDPOINT_VERSION}:{endpoint_name}:user:{authenticated_user_id}"
+
+
+def get_cached_data(db: Session, authenticated_user_id: str, cache_key: str) -> Optional[Dict[str, Any]]:
+    """Get cached data from shared DB-backed cache with validation and instrumentation."""
+    try:
+        cache_entry = db.query(StreamingCacheState).filter(
+            StreamingCacheState.user_id == authenticated_user_id,
+            StreamingCacheState.cache_key == cache_key,
+            StreamingCacheState.expires_at > datetime.utcnow()
+        ).first()
+
+        if not cache_entry:
+            logger.info(f"📭 Streaming cache MISS | key={cache_key} | user={authenticated_user_id}")
             return None
 
-def set_cached_data(cache_key: str, data: Dict[str, Any]):
-    """Set cached data with timestamp."""
-    streaming_cache[cache_key] = {
-        "data": data,
-        "timestamp": time.time()
-    }
+        payload = cache_entry.cache_payload
+        if not isinstance(payload, dict):
+            logger.warning(f"⚠️ Streaming cache deserialize failed (payload not dict) | key={cache_key} | user={authenticated_user_id}")
+            db.delete(cache_entry)
+            db.commit()
+            return None
+
+        logger.info(f"📦 Streaming cache HIT | key={cache_key} | user={authenticated_user_id}")
+        return payload
+    except Exception as e:
+        logger.error(f"❌ Streaming cache read error | key={cache_key} | user={authenticated_user_id} | error={str(e)}")
+        db.rollback()
+        return None
+
+
+def set_cached_data(db: Session, authenticated_user_id: str, cache_key: str, data: Dict[str, Any]) -> None:
+    """Store cached data in shared DB-backed cache with TTL, key cap, and serialization checks."""
+    try:
+        if not isinstance(data, dict):
+            logger.warning(f"⚠️ Streaming cache serialize skipped (data not dict) | key={cache_key} | user={authenticated_user_id}")
+            return
+
+        serialized_payload = json.loads(json.dumps(data))
+        if not isinstance(serialized_payload, dict):
+            logger.warning(f"⚠️ Streaming cache serialize skipped (post-serialize not dict) | key={cache_key} | user={authenticated_user_id}")
+            return
+
+        expiry = datetime.utcnow() + timedelta(seconds=STREAMING_CACHE_TTL_SECONDS)
+        existing = db.query(StreamingCacheState).filter(
+            StreamingCacheState.user_id == authenticated_user_id,
+            StreamingCacheState.cache_key == cache_key
+        ).first()
+
+        if existing:
+            existing.cache_payload = serialized_payload
+            existing.expires_at = expiry
+        else:
+            db.add(StreamingCacheState(
+                user_id=authenticated_user_id,
+                cache_key=cache_key,
+                cache_payload=serialized_payload,
+                expires_at=expiry
+            ))
+
+        db.flush()
+
+        # Max-key policy per user: delete oldest entries beyond cap
+        entries = db.query(StreamingCacheState).filter(
+            StreamingCacheState.user_id == authenticated_user_id
+        ).order_by(StreamingCacheState.updated_at.desc(), StreamingCacheState.id.desc()).all()
+
+        if len(entries) > STREAMING_CACHE_MAX_KEYS_PER_USER:
+            for stale_entry in entries[STREAMING_CACHE_MAX_KEYS_PER_USER:]:
+                db.delete(stale_entry)
+
+        db.commit()
+        logger.info(
+            f"💾 Streaming cache STORE | key={cache_key} | user={authenticated_user_id} | "
+            f"ttl={STREAMING_CACHE_TTL_SECONDS}s | max_keys={STREAMING_CACHE_MAX_KEYS_PER_USER}"
+        )
+    except Exception as e:
+        logger.error(f"❌ Streaming cache write error | key={cache_key} | user={authenticated_user_id} | error={str(e)}")
+        db.rollback()
 
 # Helper function to get database session
 def get_db():
     db = get_db_session()
+    try:
+        Base.metadata.create_all(bind=db.bind, tables=[StreamingCacheState.__table__], checkfirst=True)
+    except Exception as table_error:
+        logger.warning(f"⚠️ Could not ensure streaming cache table exists: {str(table_error)}")
     try:
         yield db
     finally:
@@ -151,8 +224,8 @@ async def stream_strategic_intelligence(
             logger.info(f"🚀 Starting strategic intelligence stream for authenticated user: {authenticated_user_id}")
             
             # Check cache first
-            cache_key = f"strategic_intelligence_{authenticated_user_id}"
-            cached_data = get_cached_data(cache_key)
+            cache_key = _build_cache_key("strategic-intelligence", authenticated_user_id)
+            cached_data = get_cached_data(db, authenticated_user_id, cache_key)
             if cached_data:
                 logger.info(f"✅ Returning cached strategic intelligence data for user: {authenticated_user_id}")
                 yield {"type": "result", "status": "success", "data": cached_data, "progress": 100}
@@ -241,7 +314,7 @@ async def stream_strategic_intelligence(
             }
             
             # Cache the strategic intelligence data
-            set_cached_data(cache_key, strategic_intelligence)
+            set_cached_data(db, authenticated_user_id, cache_key, strategic_intelligence)
             
             # Send progress update
             yield {"type": "progress", "message": "Finalizing strategic intelligence...", "progress": 80}
@@ -288,8 +361,8 @@ async def stream_keyword_research(
             logger.info(f"🚀 Starting keyword research stream for authenticated user: {authenticated_user_id}")
             
             # Check cache first
-            cache_key = f"keyword_research_{authenticated_user_id}"
-            cached_data = get_cached_data(cache_key)
+            cache_key = _build_cache_key("keyword-research", authenticated_user_id)
+            cached_data = get_cached_data(db, authenticated_user_id, cache_key)
             if cached_data:
                 logger.info(f"✅ Returning cached keyword research data for user: {authenticated_user_id}")
                 yield {"type": "result", "status": "success", "data": cached_data, "progress": 100}
@@ -359,7 +432,7 @@ async def stream_keyword_research(
             }
             
             # Cache the keyword data
-            set_cached_data(cache_key, keyword_data)
+            set_cached_data(db, authenticated_user_id, cache_key, keyword_data)
             
             # Send progress update
             yield {"type": "progress", "message": "Finalizing keyword research...", "progress": 80}