SurfSense/surfsense_backend/app/indexing_pipeline/cache/cached_indexing.py

121 lines
4.5 KiB
Python

"""Entry point: serve chunk embeddings from cache, embedding only on a miss.
Embeddings are a pure function of the markdown, the embedding model, and the
chunker -- so identical markdown is chunked and embedded once and reused across
workspaces, even when it came from different sources.
"""
from __future__ import annotations
import asyncio
import hashlib
import logging
import numpy as np
from app.config import config
from app.indexing_pipeline.cache.eligibility import is_index_cacheable
from app.indexing_pipeline.cache.schemas import CachedChunk, EmbeddingKey, EmbeddingSet
from app.indexing_pipeline.cache.service import IndexCacheService
from app.indexing_pipeline.cache.settings import load_index_cache_settings
from app.indexing_pipeline.document_chunker import chunk_text, chunk_text_hybrid
from app.indexing_pipeline.document_embedder import embed_texts
from app.observability import metrics
logger = logging.getLogger(__name__)
ChunkPair = tuple[str, np.ndarray]
async def build_chunk_embeddings(
markdown: str, *, use_code_chunker: bool
) -> tuple[np.ndarray, list[ChunkPair]]:
"""Return the document-level vector and ordered ``(chunk_text, vector)`` pairs.
Drop-in for the inline chunk+embed step; reuses prior output when the same
markdown has already been embedded with the current model and chunker.
"""
settings = load_index_cache_settings()
chunker_kind = "code" if use_code_chunker else "hybrid"
embedding_dim = getattr(config.embedding_model_instance, "dimension", None)
cacheable = is_index_cacheable(
cache_enabled=settings.enabled,
embedding_model=config.EMBEDDING_MODEL,
embedding_dim=embedding_dim,
)
if not cacheable:
return await _compute(markdown, use_code_chunker=use_code_chunker)
key = EmbeddingKey(
markdown_sha256=_hash_text(markdown),
embedding_model=config.EMBEDDING_MODEL,
embedding_dim=int(embedding_dim),
chunker_kind=chunker_kind,
chunker_version=settings.chunker_version,
)
cached = await _recall(key)
if cached is not None:
metrics.record_index_cache_lookup(
embedding_model=key.embedding_model, chunker_kind=chunker_kind, outcome="hit"
)
logger.debug("Index cache hit for %s", key.markdown_sha256)
return cached.summary_embedding, [(c.text, c.embedding) for c in cached.chunks]
metrics.record_index_cache_lookup(
embedding_model=key.embedding_model, chunker_kind=chunker_kind, outcome="miss"
)
summary_embedding, chunk_pairs = await _compute(
markdown, use_code_chunker=use_code_chunker
)
await _remember(key, summary_embedding, chunk_pairs)
return summary_embedding, chunk_pairs
async def _compute(
markdown: str, *, use_code_chunker: bool
) -> tuple[np.ndarray, list[ChunkPair]]:
if use_code_chunker:
chunk_texts = await asyncio.to_thread(
chunk_text, markdown, use_code_chunker=True
)
else:
# Table-aware hybrid chunker keeps Markdown tables intact (issue #1334).
chunk_texts = await asyncio.to_thread(chunk_text_hybrid, markdown)
embeddings = await asyncio.to_thread(embed_texts, [markdown, *chunk_texts])
summary_embedding, *chunk_embeddings = embeddings
return summary_embedding, list(zip(chunk_texts, chunk_embeddings, strict=False))
async def _recall(key: EmbeddingKey) -> EmbeddingSet | None:
# Caching is best-effort: any failure falls through to a normal embed.
try:
from app.tasks.celery_tasks import get_celery_session_maker
async with get_celery_session_maker()() as session:
return await IndexCacheService(session).recall(key)
except Exception:
logger.warning("Index cache recall failed; embedding fresh", exc_info=True)
return None
async def _remember(
key: EmbeddingKey, summary_embedding: np.ndarray, chunk_pairs: list[ChunkPair]
) -> None:
try:
from app.tasks.celery_tasks import get_celery_session_maker
embedding_set = EmbeddingSet(
summary_embedding=summary_embedding,
chunks=[CachedChunk(text=text, embedding=vec) for text, vec in chunk_pairs],
)
async with get_celery_session_maker()() as session:
await IndexCacheService(session).remember(key, embedding_set)
except Exception:
logger.warning("Index cache write failed; result not cached", exc_info=True)
def _hash_text(text: str) -> str:
return hashlib.sha256(text.encode("utf-8")).hexdigest()