introduce a new service called metadata_relay to implement caching for TMDB and TVDB API responses with valkey

metadata_relay/app/cache.py

@@ -0,0 +1,65 @@
+import json
+import hashlib
+import logging
+from typing import Any, Optional
+import valkey.asyncio as valkey
+import os
+from functools import wraps
+import asyncio
+import inspect
+
+log = logging.getLogger(__name__)
+
+redis_client = valkey.Redis(
+    host=os.getenv("VALKEY_HOST", "localhost"),
+    port=int(os.getenv("VALKEY_PORT", 6379)),
+    db=int(os.getenv("VALKEY_DB", 0)),
+    decode_responses=True,
+)
+
+
+def generate_cache_key(prefix: str, *args, **kwargs) -> str:
+    key_data = f"{prefix}:{args}:{sorted(kwargs.items())}"
+    return hashlib.md5(key_data.encode()).hexdigest()
+
+
+async def get_cached_response(cache_key: str) -> Optional[Any]:
+    try:
+        cached_data = await redis_client.get(cache_key)
+        if cached_data:
+            return json.loads(cached_data)
+        return None
+    except Exception as e:
+        log.error(f"Error getting cached response: {e}")
+        return None
+
+
+async def set_cached_response(cache_key: str, data: Any, ttl: int = 3600) -> bool:
+    try:
+        await redis_client.setex(cache_key, ttl, json.dumps(data, default=str))
+        return True
+    except Exception as e:
+        log.error(f"Error setting cached response: {e}")
+        return False
+
+
+def cache_response(prefix: str, ttl: int = 3600):
+    def decorator(func):
+        @wraps(func)
+        async def wrapper(*args, **kwargs):
+            cache_key = generate_cache_key(prefix, *args, **kwargs)
+
+            cached_response = await get_cached_response(cache_key)
+            if cached_response is not None:
+                log.info(f"Cache hit for key: {cache_key}")
+                return cached_response
+
+            log.info(f"Cache miss for key: {cache_key}")
+
+            response = await func(*args, **kwargs)
+
+            await set_cached_response(cache_key, response, ttl)
+
+            return response
+        return wrapper
+    return decorator