refactor: chat and base searcher
This commit is contained in:
136
packages/leann-core/src/leann/chat.py
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136
packages/leann-core/src/leann/chat.py
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#!/usr/bin/env python3
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"""
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This file contains the chat generation logic for the LEANN project,
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supporting different backends like Ollama, Hugging Face Transformers, and a simulation mode.
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"""
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from abc import ABC, abstractmethod
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from typing import Dict, Any, Optional
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import logging
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# Configure logging
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logging.basicConfig(level=logging.INFO)
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logger = logging.getLogger(__name__)
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class LLMInterface(ABC):
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"""Abstract base class for a generic Language Model (LLM) interface."""
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@abstractmethod
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def ask(self, prompt: str, **kwargs) -> str:
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"""
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Sends a prompt to the LLM and returns the generated text.
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Args:
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prompt: The input prompt for the LLM.
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**kwargs: Additional keyword arguments for the LLM backend.
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Returns:
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The response string from the LLM.
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"""
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pass
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class OllamaChat(LLMInterface):
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"""LLM interface for Ollama models."""
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def __init__(self, model: str = "llama3:8b", host: str = "http://localhost:11434"):
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self.model = model
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self.host = host
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logger.info(f"Initializing OllamaChat with model='{model}' and host='{host}'")
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try:
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import requests
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# Check if the Ollama server is responsive
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if host:
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requests.get(host)
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except ImportError:
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raise ImportError("The 'requests' library is required for Ollama. Please install it with 'pip install requests'.")
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except requests.exceptions.ConnectionError:
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logger.error(f"Could not connect to Ollama at {host}. Please ensure Ollama is running.")
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raise ConnectionError(f"Could not connect to Ollama at {host}. Please ensure Ollama is running.")
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def ask(self, prompt: str, **kwargs) -> str:
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import requests
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import json
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full_url = f"{self.host}/api/generate"
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payload = {
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"model": self.model,
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"prompt": prompt,
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"stream": False, # Keep it simple for now
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"options": kwargs
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}
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logger.info(f"Sending request to Ollama: {payload}")
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try:
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response = requests.post(full_url, data=json.dumps(payload))
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response.raise_for_status()
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# The response from Ollama can be a stream of JSON objects, handle this
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response_parts = response.text.strip().split('\n')
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full_response = ""
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for part in response_parts:
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if part:
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json_part = json.loads(part)
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full_response += json_part.get("response", "")
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if json_part.get("done"):
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break
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return full_response
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except requests.exceptions.RequestException as e:
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logger.error(f"Error communicating with Ollama: {e}")
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return f"Error: Could not get a response from Ollama. Details: {e}"
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class HFChat(LLMInterface):
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"""LLM interface for local Hugging Face Transformers models."""
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def __init__(self, model_name: str = "deepseek-ai/deepseek-llm-7b-chat"):
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logger.info(f"Initializing HFChat with model='{model_name}'")
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try:
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from transformers import pipeline
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except ImportError:
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raise ImportError("The 'transformers' library is required for Hugging Face models. Please install it with 'pip install transformers'.")
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self.pipeline = pipeline("text-generation", model=model_name)
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def ask(self, prompt: str, **kwargs) -> str:
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# Sensible defaults for text generation
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params = {
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"max_length": 500,
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"num_return_sequences": 1,
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**kwargs
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}
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logger.info(f"Generating text with Hugging Face model with params: {params}")
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results = self.pipeline(prompt, **params)
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return results[0]['generated_text']
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class SimulatedChat(LLMInterface):
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"""A simple simulated chat for testing and development."""
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def ask(self, prompt: str, **kwargs) -> str:
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logger.info("Simulating LLM call...")
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print("Prompt sent to LLM (simulation):", prompt[:500] + "...")
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return "This is a simulated answer from the LLM based on the retrieved context."
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def get_llm(llm_config: Optional[Dict[str, Any]] = None) -> LLMInterface:
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"""
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Factory function to get an LLM interface based on configuration.
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Args:
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llm_config: A dictionary specifying the LLM type and its parameters.
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Example: {"type": "ollama", "model": "llama3"}
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{"type": "hf", "model": "distilgpt2"}
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None (for simulation mode)
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Returns:
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An instance of an LLMInterface subclass.
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"""
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if llm_config is None:
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logger.info("No LLM config provided, defaulting to simulated chat.")
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return SimulatedChat()
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llm_type = llm_config.get("type", "simulated")
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model = llm_config.get("model")
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logger.info(f"Attempting to create LLM of type='{llm_type}' with model='{model}'")
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if llm_type == "ollama":
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return OllamaChat(model=model, host=llm_config.get("host"))
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elif llm_type == "hf":
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return HFChat(model_name=model)
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elif llm_type == "simulated":
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return SimulatedChat()
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else:
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raise ValueError(f"Unknown LLM type: '{llm_type}'")
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97
packages/leann-core/src/leann/searcher_base.py
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97
packages/leann-core/src/leann/searcher_base.py
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@@ -0,0 +1,97 @@
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import json
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import pickle
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from abc import ABC, abstractmethod
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from pathlib import Path
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from typing import Dict, Any, List
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import numpy as np
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from .embedding_server_manager import EmbeddingServerManager
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from .interface import LeannBackendSearcherInterface
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class BaseSearcher(LeannBackendSearcherInterface, ABC):
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"""
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Abstract base class for Leann searchers, containing common logic for
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loading metadata, managing embedding servers, and handling file paths.
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"""
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def __init__(self, index_path: str, backend_module_name: str, **kwargs):
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"""
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Initializes the BaseSearcher.
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Args:
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index_path: Path to the Leann index file (e.g., '.../my_index.leann').
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backend_module_name: The specific embedding server module to use
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(e.g., 'leann_backend_hnsw.hnsw_embedding_server').
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**kwargs: Additional keyword arguments.
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"""
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self.index_path = Path(index_path)
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self.index_dir = self.index_path.parent
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self.meta = kwargs.get("meta", self._load_meta())
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if not self.meta:
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raise ValueError("Searcher requires metadata from .meta.json.")
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self.dimensions = self.meta.get("dimensions")
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if not self.dimensions:
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raise ValueError("Dimensions not found in Leann metadata.")
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self.embedding_model = self.meta.get("embedding_model")
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if not self.embedding_model:
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print("WARNING: embedding_model not found in meta.json. Recompute will fail.")
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self.label_map = self._load_label_map()
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self.embedding_server_manager = EmbeddingServerManager(
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backend_module_name=backend_module_name
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)
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def _load_meta(self) -> Dict[str, Any]:
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"""Loads the metadata file associated with the index."""
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# This is the corrected logic for finding the meta file.
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meta_path = self.index_dir / f"{self.index_path.name}.meta.json"
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if not meta_path.exists():
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raise FileNotFoundError(f"Leann metadata file not found at {meta_path}")
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with open(meta_path, 'r', encoding='utf-8') as f:
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return json.load(f)
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def _load_label_map(self) -> Dict[int, str]:
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"""Loads the mapping from integer IDs to string IDs."""
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label_map_file = self.index_dir / "leann.labels.map"
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if not label_map_file.exists():
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raise FileNotFoundError(f"Label map file not found: {label_map_file}")
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with open(label_map_file, 'rb') as f:
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return pickle.load(f)
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def _ensure_server_running(self, passages_source_file: str, port: int, **kwargs) -> None:
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"""
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Ensures the embedding server is running if recompute is needed.
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This is a helper for subclasses.
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"""
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if not self.embedding_model:
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raise ValueError("Cannot use recompute mode without 'embedding_model' in meta.json.")
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server_started = self.embedding_server_manager.start_server(
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port=port,
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model_name=self.embedding_model,
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passages_file=passages_source_file,
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distance_metric=kwargs.get("distance_metric"),
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)
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if not server_started:
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raise RuntimeError(f"Failed to start embedding server on port {kwargs.get('zmq_port')}")
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@abstractmethod
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def search(self, query: np.ndarray, top_k: int, **kwargs) -> Dict[str, Any]:
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"""
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Search for the top_k nearest neighbors of the query vector.
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Must be implemented by subclasses.
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"""
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pass
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def __del__(self):
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"""Ensures the embedding server is stopped when the searcher is destroyed."""
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if hasattr(self, 'embedding_server_manager'):
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self.embedding_server_manager.stop_server()
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