File size: 2,656 Bytes
df4a21a | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 | """
Cache service for managing cached data.
Note: For Milestone 1, this is a simple placeholder.
Future milestones may add more sophisticated caching.
"""
from typing import Any, Dict, Optional
import hashlib
import time
from app.core.logging import get_logger
logger = get_logger(__name__)
class CacheService:
"""
Simple in-memory cache service.
This is a basic implementation for Milestone 1.
Future versions may use Redis or other backends.
"""
def __init__(self, max_size: int = 100, ttl_seconds: int = 3600):
"""
Initialize the cache service.
Args:
max_size: Maximum number of items to cache
ttl_seconds: Time-to-live for cache entries in seconds
"""
self._cache: Dict[str, Dict[str, Any]] = {}
self.max_size = max_size
self.ttl_seconds = ttl_seconds
def _generate_key(self, data: bytes) -> str:
"""Generate a cache key from data (SHA256 hash)."""
return hashlib.sha256(data).hexdigest()
def get(self, key: str) -> Optional[Any]:
"""
Get a value from cache.
Args:
key: Cache key
Returns:
Cached value or None if not found/expired
"""
entry = self._cache.get(key)
if entry is None:
return None
# Check TTL
if time.time() - entry["timestamp"] > self.ttl_seconds:
del self._cache[key]
return None
return entry["value"]
def set(self, key: str, value: Any) -> None:
"""
Set a value in cache.
Args:
key: Cache key
value: Value to cache
"""
# Simple eviction: remove oldest if at max size
if len(self._cache) >= self.max_size:
oldest_key = min(self._cache.keys(), key=lambda k: self._cache[k]["timestamp"])
del self._cache[oldest_key]
self._cache[key] = {
"value": value,
"timestamp": time.time()
}
def clear(self) -> None:
"""Clear all cached entries."""
self._cache.clear()
def size(self) -> int:
"""Get current cache size."""
return len(self._cache)
# Global singleton instance
_cache_service: Optional[CacheService] = None
def get_cache_service() -> CacheService:
"""
Get the global cache service instance.
Returns:
CacheService instance
"""
global _cache_service
if _cache_service is None:
_cache_service = CacheService()
return _cache_service
|