Files
LEANN/packages/leann-core/src/leann/searcher_base.py

99 lines
3.7 KiB
Python

import json
import pickle
from abc import ABC, abstractmethod
from pathlib import Path
from typing import Dict, Any, List
import numpy as np
from .embedding_server_manager import EmbeddingServerManager
from .interface import LeannBackendSearcherInterface
class BaseSearcher(LeannBackendSearcherInterface, ABC):
"""
Abstract base class for Leann searchers, containing common logic for
loading metadata, managing embedding servers, and handling file paths.
"""
def __init__(self, index_path: str, backend_module_name: str, **kwargs):
"""
Initializes the BaseSearcher.
Args:
index_path: Path to the Leann index file (e.g., '.../my_index.leann').
backend_module_name: The specific embedding server module to use
(e.g., 'leann_backend_hnsw.hnsw_embedding_server').
**kwargs: Additional keyword arguments.
"""
self.index_path = Path(index_path)
self.index_dir = self.index_path.parent
self.meta = kwargs.get("meta", self._load_meta())
if not self.meta:
raise ValueError("Searcher requires metadata from .meta.json.")
self.dimensions = self.meta.get("dimensions")
if not self.dimensions:
raise ValueError("Dimensions not found in Leann metadata.")
self.embedding_model = self.meta.get("embedding_model")
if not self.embedding_model:
print("WARNING: embedding_model not found in meta.json. Recompute will fail.")
self.label_map = self._load_label_map()
self.embedding_server_manager = EmbeddingServerManager(
backend_module_name=backend_module_name
)
def _load_meta(self) -> Dict[str, Any]:
"""Loads the metadata file associated with the index."""
# This is the corrected logic for finding the meta file.
meta_path = self.index_dir / f"{self.index_path.name}.meta.json"
if not meta_path.exists():
raise FileNotFoundError(f"Leann metadata file not found at {meta_path}")
with open(meta_path, 'r', encoding='utf-8') as f:
return json.load(f)
def _load_label_map(self) -> Dict[int, str]:
"""Loads the mapping from integer IDs to string IDs."""
label_map_file = self.index_dir / "leann.labels.map"
if not label_map_file.exists():
raise FileNotFoundError(f"Label map file not found: {label_map_file}")
with open(label_map_file, 'rb') as f:
return pickle.load(f)
def _ensure_server_running(self, passages_source_file: str, port: int, **kwargs) -> None:
"""
Ensures the embedding server is running if recompute is needed.
This is a helper for subclasses.
"""
if not self.embedding_model:
raise ValueError("Cannot use recompute mode without 'embedding_model' in meta.json.")
server_started = self.embedding_server_manager.start_server(
port=port,
model_name=self.embedding_model,
passages_file=passages_source_file,
distance_metric=kwargs.get("distance_metric"),
use_mlx=kwargs.get("use_mlx", False),
)
if not server_started:
raise RuntimeError(f"Failed to start embedding server on port {port}")
@abstractmethod
def search(self, query: np.ndarray, top_k: int, **kwargs) -> Dict[str, Any]:
"""
Search for the top_k nearest neighbors of the query vector.
Must be implemented by subclasses.
"""
pass
def __del__(self):
"""Ensures the embedding server is stopped when the searcher is destroyed."""
if hasattr(self, 'embedding_server_manager'):
self.embedding_server_manager.stop_server()