Odysseus v1.0

src/search/cache.py

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+"""Search and content caching with LRU eviction."""
+
+import hashlib
+import logging
+from datetime import datetime, timedelta
+from pathlib import Path
+from typing import Dict
+
+logger = logging.getLogger(__name__)
+
+# Cache directories
+CACHE_DIR = Path(__file__).resolve().parent.parent / "cache"
+SEARCH_CACHE_DIR = CACHE_DIR / "search"
+CONTENT_CACHE_DIR = CACHE_DIR / "content"
+CACHE_MAX_ENTRIES = 1000
+
+# Create cache directories
+SEARCH_CACHE_DIR.mkdir(parents=True, exist_ok=True)
+CONTENT_CACHE_DIR.mkdir(parents=True, exist_ok=True)
+
+# Track cache size for LRU eviction
+search_cache_index: Dict[str, datetime] = {}
+content_cache_index: Dict[str, datetime] = {}
+
+# Cache metrics (shared across modules)
+cache_metrics = {"hits": 0, "misses": 0, "evictions": 0}
+
+
+def generate_cache_key(data: str) -> str:
+    """Generate a unique cache key using SHA-256 hash."""
+    return hashlib.sha256(data.encode("utf-8")).hexdigest()
+
+
+def cleanup_cache(cache_dir: Path, cache_index: Dict[str, datetime], max_age: timedelta):
+    """Remove expired cache entries and enforce LRU policy."""
+    current_time = datetime.now()
+    files_in_dir = {f.name.split(".")[0]: f for f in cache_dir.glob("*.cache")}
+
+    to_remove = []
+    for key, timestamp in list(cache_index.items()):
+        if current_time - timestamp > max_age or key not in files_in_dir:
+            to_remove.append(key)
+            if key in files_in_dir:
+                files_in_dir[key].unlink(missing_ok=True)
+
+    for key in to_remove:
+        cache_index.pop(key, None)
+        cache_metrics["evictions"] += 1
+
+    if len(cache_index) > CACHE_MAX_ENTRIES:
+        sorted_items = sorted(cache_index.items(), key=lambda x: x[1])
+        excess_count = len(cache_index) - CACHE_MAX_ENTRIES
+        for key, _ in sorted_items[:excess_count]:
+            cache_index.pop(key, None)
+            cache_file = cache_dir / f"{key}.cache"
+            cache_file.unlink(missing_ok=True)
+            cache_metrics["evictions"] += 1