dify/api/core/embedding/cached_embedding.py
2024-02-01 18:11:57 +08:00

94 lines
3.7 KiB
Python

import base64
import json
import logging
from typing import List, Optional, cast
import numpy as np
from core.model_manager import ModelInstance
from core.model_runtime.entities.model_entities import ModelPropertyKey
from core.model_runtime.model_providers.__base.text_embedding_model import TextEmbeddingModel
from extensions.ext_database import db
from extensions.ext_redis import redis_client
from langchain.embeddings.base import Embeddings
from libs import helper
from models.dataset import Embedding
from sqlalchemy.exc import IntegrityError
logger = logging.getLogger(__name__)
class CacheEmbedding(Embeddings):
def __init__(self, model_instance: ModelInstance, user: Optional[str] = None) -> None:
self._model_instance = model_instance
self._user = user
def embed_documents(self, texts: List[str]) -> List[List[float]]:
"""Embed search docs in batches of 10."""
text_embeddings = []
try:
model_type_instance = cast(TextEmbeddingModel, self._model_instance.model_type_instance)
model_schema = model_type_instance.get_model_schema(self._model_instance.model, self._model_instance.credentials)
max_chunks = model_schema.model_properties[ModelPropertyKey.MAX_CHUNKS] \
if model_schema and ModelPropertyKey.MAX_CHUNKS in model_schema.model_properties else 1
for i in range(0, len(texts), max_chunks):
batch_texts = texts[i:i + max_chunks]
embedding_result = self._model_instance.invoke_text_embedding(
texts=batch_texts,
user=self._user
)
for vector in embedding_result.embeddings:
try:
normalized_embedding = (vector / np.linalg.norm(vector)).tolist()
text_embeddings.append(normalized_embedding)
except IntegrityError:
db.session.rollback()
except Exception as e:
logging.exception('Failed to add embedding to redis')
except Exception as ex:
logger.error('Failed to embed documents: ', ex)
raise ex
return text_embeddings
def embed_query(self, text: str) -> List[float]:
"""Embed query text."""
# use doc embedding cache or store if not exists
hash = helper.generate_text_hash(text)
embedding_cache_key = f'{self._model_instance.provider}_{self._model_instance.model}_{hash}'
embedding = redis_client.get(embedding_cache_key)
if embedding:
redis_client.expire(embedding_cache_key, 600)
return list(np.frombuffer(base64.b64decode(embedding), dtype="float"))
try:
embedding_result = self._model_instance.invoke_text_embedding(
texts=[text],
user=self._user
)
embedding_results = embedding_result.embeddings[0]
embedding_results = (embedding_results / np.linalg.norm(embedding_results)).tolist()
except Exception as ex:
raise ex
try:
# encode embedding to base64
embedding_vector = np.array(embedding_results)
vector_bytes = embedding_vector.tobytes()
# Transform to Base64
encoded_vector = base64.b64encode(vector_bytes)
# Transform to string
encoded_str = encoded_vector.decode("utf-8")
redis_client.setex(embedding_cache_key, 600, encoded_str)
except IntegrityError:
db.session.rollback()
except:
logging.exception('Failed to add embedding to redis')
return embedding_results