Redis®*: The same in Python
This documentation is part of the Vector search and RAG guide. View the full guide here: Semantic search, recommendations, and retrieval-augmented generation with Redis.
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import os
import numpy as np
import redis
from redis.commands.search.field import TextField, TagField, VectorField
from redis.commands.search.index_definition import IndexDefinition, IndexType
from redis.commands.search.query import Query
DIMENSIONS = 1536
r = redis.from_url(os.environ['STACKHERO_REDIS_URL_TLS'])
# Create the index once, at startup
try:
r.ft('chunksIndex').create_index(
(
TextField('content'),
TagField('documentId'),
VectorField(
'embedding',
'HNSW',
{'TYPE': 'FLOAT32', 'DIM': DIMENSIONS, 'DISTANCE_METRIC': 'COSINE'},
),
),
definition=IndexDefinition(prefix=['chunk:'], index_type=IndexType.HASH),
)
except redis.ResponseError as error:
if 'Index already exists' not in str(error):
raise
def index_chunk(chunk_id, document_id, content, embedding):
r.hset(
f'chunk:{chunk_id}',
mapping={
'content': content,
'documentId': document_id,
'embedding': np.array(embedding, dtype=np.float32).tobytes(),
},
)
def retrieve(question_embedding, document_id, count=5):
query = (
Query(f'(@documentId:{{{document_id}}})=>[KNN {count} @embedding $queryVector AS score]')
.sort_by('score')
.return_fields('content', 'score')
.dialect(2)
)
results = r.ft('chunksIndex').search(
query,
query_params={'queryVector': np.array(question_embedding, dtype=np.float32).tobytes()},
)
return [document.content for document in results.docs]