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hkuds--lightrag/lightrag/kg/deprecated/chroma_impl.py
T
2026-07-13 12:08:54 +08:00

345 lines
13 KiB
Python

import asyncio
import os
from dataclasses import dataclass
from typing import Any, final
import numpy as np
from lightrag.base import BaseVectorStorage
from lightrag.constants import DEFAULT_QUERY_PRIORITY
from lightrag.utils import logger
import pipmaster as pm
if not pm.is_installed("chromadb"):
pm.install("chromadb")
from chromadb import HttpClient, PersistentClient # type: ignore
from chromadb.config import Settings # type: ignore
@final
@dataclass
class ChromaVectorDBStorage(BaseVectorStorage):
"""ChromaDB vector storage implementation."""
def __post_init__(self):
self._validate_embedding_func()
try:
config = self.global_config.get("vector_db_storage_cls_kwargs", {})
cosine_threshold = config.get("cosine_better_than_threshold")
if cosine_threshold is None:
raise ValueError(
"cosine_better_than_threshold must be specified in vector_db_storage_cls_kwargs"
)
self.cosine_better_than_threshold = cosine_threshold
user_collection_settings = config.get("collection_settings", {})
# Default HNSW index settings for ChromaDB
default_collection_settings = {
# Distance metric used for similarity search (cosine similarity)
"hnsw:space": "cosine",
# Number of nearest neighbors to explore during index construction
# Higher values = better recall but slower indexing
"hnsw:construction_ef": 128,
# Number of nearest neighbors to explore during search
# Higher values = better recall but slower search
"hnsw:search_ef": 128,
# Number of connections per node in the HNSW graph
# Higher values = better recall but more memory usage
"hnsw:M": 16,
# Number of vectors to process in one batch during indexing
"hnsw:batch_size": 100,
# Number of updates before forcing index synchronization
# Lower values = more frequent syncs but slower indexing
"hnsw:sync_threshold": 1000,
}
collection_settings = {
**default_collection_settings,
**user_collection_settings,
}
local_path = config.get("local_path", None)
if local_path:
self._client = PersistentClient(
path=local_path,
settings=Settings(
allow_reset=True,
anonymized_telemetry=False,
),
)
else:
auth_provider = config.get(
"auth_provider", "chromadb.auth.token_authn.TokenAuthClientProvider"
)
auth_credentials = config.get("auth_token", "secret-token")
headers = {}
if "token_authn" in auth_provider:
headers = {
config.get(
"auth_header_name", "X-Chroma-Token"
): auth_credentials
}
elif "basic_authn" in auth_provider:
auth_credentials = config.get("auth_credentials", "admin:admin")
self._client = HttpClient(
host=config.get("host", "localhost"),
port=config.get("port", 8000),
headers=headers,
settings=Settings(
chroma_api_impl="rest",
chroma_client_auth_provider=auth_provider,
chroma_client_auth_credentials=auth_credentials,
allow_reset=True,
anonymized_telemetry=False,
),
)
self._collection = self._client.get_or_create_collection(
name=self.namespace,
metadata={
**collection_settings,
"dimension": self.embedding_func.embedding_dim,
},
)
# Use batch size from collection settings if specified
self._max_batch_size = self.global_config.get(
"embedding_batch_num", collection_settings.get("hnsw:batch_size", 32)
)
except Exception as e:
logger.error(f"ChromaDB initialization failed: {str(e)}")
raise
async def upsert(self, data: dict[str, dict[str, Any]]) -> None:
logger.debug(f"Inserting {len(data)} to {self.namespace}")
if not data:
return
try:
import time
current_time = int(time.time())
ids = list(data.keys())
documents = [v["content"] for v in data.values()]
metadatas = [
{
**{k: v for k, v in item.items() if k in self.meta_fields},
"created_at": current_time,
}
or {"_default": "true", "created_at": current_time}
for item in data.values()
]
# Process in batches
batches = [
documents[i : i + self._max_batch_size]
for i in range(0, len(documents), self._max_batch_size)
]
embedding_tasks = [self.embedding_func(batch) for batch in batches]
embeddings_list = []
# Pre-allocate embeddings_list with known size
embeddings_list = [None] * len(embedding_tasks)
# Use asyncio.gather instead of as_completed if order doesn't matter
embeddings_results = await asyncio.gather(*embedding_tasks)
embeddings_list = list(embeddings_results)
embeddings = np.concatenate(embeddings_list)
# Upsert in batches
for i in range(0, len(ids), self._max_batch_size):
batch_slice = slice(i, i + self._max_batch_size)
self._collection.upsert(
ids=ids[batch_slice],
embeddings=embeddings[batch_slice].tolist(),
documents=documents[batch_slice],
metadatas=metadatas[batch_slice],
)
return ids
except Exception as e:
logger.error(f"Error during ChromaDB upsert: {str(e)}")
raise
async def query(self, query: str, top_k: int) -> list[dict[str, Any]]:
try:
embedding = await self.embedding_func(
[query], _priority=DEFAULT_QUERY_PRIORITY
) # higher priority for query
results = self._collection.query(
query_embeddings=embedding.tolist()
if not isinstance(embedding, list)
else embedding,
n_results=top_k * 2, # Request more results to allow for filtering
include=["metadatas", "distances", "documents"],
)
# Filter results by cosine similarity threshold and take top k
# We request 2x results initially to have enough after filtering
# ChromaDB returns cosine similarity (1 = identical, 0 = orthogonal)
# We convert to distance (0 = identical, 1 = orthogonal) via (1 - similarity)
# Only keep results with distance below threshold, then take top k
return [
{
"id": results["ids"][0][i],
"distance": 1 - results["distances"][0][i],
"content": results["documents"][0][i],
"created_at": results["metadatas"][0][i].get("created_at"),
**results["metadatas"][0][i],
}
for i in range(len(results["ids"][0]))
if (1 - results["distances"][0][i]) >= self.cosine_better_than_threshold
][:top_k]
except Exception as e:
logger.error(f"Error during ChromaDB query: {str(e)}")
raise
async def index_done_callback(self) -> None:
# ChromaDB handles persistence automatically
pass
async def delete_entity(self, entity_name: str) -> None:
"""Delete an entity by its ID.
Args:
entity_name: The ID of the entity to delete
"""
try:
logger.info(f"Deleting entity with ID {entity_name} from {self.namespace}")
self._collection.delete(ids=[entity_name])
except Exception as e:
logger.error(f"Error during entity deletion: {str(e)}")
raise
async def delete_entity_relation(self, entity_name: str) -> None:
"""Delete an entity and its relations by ID.
In vector DB context, this is equivalent to delete_entity.
Args:
entity_name: The ID of the entity to delete
"""
await self.delete_entity(entity_name)
async def delete(self, ids: list[str]) -> None:
"""Delete vectors with specified IDs
Args:
ids: List of vector IDs to be deleted
"""
try:
self._collection.delete(ids=ids)
logger.debug(
f"Successfully deleted {len(ids)} vectors from {self.namespace}"
)
except Exception as e:
logger.error(f"Error while deleting vectors from {self.namespace}: {e}")
raise
except Exception as e:
logger.error(f"Error during prefix search in ChromaDB: {str(e)}")
raise
async def get_by_id(self, id: str) -> dict[str, Any] | None:
"""Get vector data by its ID
Args:
id: The unique identifier of the vector
Returns:
The vector data if found, or None if not found
"""
try:
# Query the collection for a single vector by ID
result = self._collection.get(
ids=[id], include=["metadatas", "embeddings", "documents"]
)
if not result or not result["ids"] or len(result["ids"]) == 0:
return None
# Format the result to match the expected structure
return {
"id": result["ids"][0],
"vector": result["embeddings"][0],
"content": result["documents"][0],
"created_at": result["metadatas"][0].get("created_at"),
**result["metadatas"][0],
}
except Exception as e:
logger.error(f"Error retrieving vector data for ID {id}: {e}")
return None
async def get_by_ids(self, ids: list[str]) -> list[dict[str, Any]]:
"""Get multiple vector data by their IDs
Args:
ids: List of unique identifiers
Returns:
List of vector data objects that were found
"""
if not ids:
return []
try:
# Query the collection for multiple vectors by IDs
result = self._collection.get(
ids=ids, include=["metadatas", "embeddings", "documents"]
)
if not result or not result["ids"] or len(result["ids"]) == 0:
return []
# Format the results to match the expected structure and preserve ordering
formatted_map: dict[str, dict[str, Any]] = {}
for i, result_id in enumerate(result["ids"]):
record = {
"id": result_id,
"vector": result["embeddings"][i],
"content": result["documents"][i],
"created_at": result["metadatas"][i].get("created_at"),
**result["metadatas"][i],
}
formatted_map[str(result_id)] = record
ordered_results: list[dict[str, Any] | None] = []
for requested_id in ids:
ordered_results.append(formatted_map.get(str(requested_id)))
return ordered_results
except Exception as e:
logger.error(f"Error retrieving vector data for IDs {ids}: {e}")
return []
async def drop(self) -> dict[str, str]:
"""Drop all vector data from storage and clean up resources
This method will delete all documents from the ChromaDB collection.
Returns:
dict[str, str]: Operation status and message
- On success: {"status": "success", "message": "data dropped"}
- On failure: {"status": "error", "message": "<error details>"}
"""
try:
# Get all IDs in the collection
result = self._collection.get(include=[])
if result and result["ids"] and len(result["ids"]) > 0:
# Delete all documents
self._collection.delete(ids=result["ids"])
logger.info(
f"Process {os.getpid()} drop ChromaDB collection {self.namespace}"
)
return {"status": "success", "message": "data dropped"}
except Exception as e:
logger.error(f"Error dropping ChromaDB collection {self.namespace}: {e}")
return {"status": "error", "message": str(e)}