ReMe/reme2/component/embedding/base_embedding_model.py
jinli.yl baf110e602
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feat(components): add token counter and file-based utility components
- Introduce BaseAsTokenCounter and EstimatedAsTokenCounter for token estimation
- Add AsMsgStat and AsBlockStat schema for message statistics tracking
- Implement FileIO class with read/write/append/edit operations
- Create file utility functions for safe async file reading and truncation
- Add MemorySearch component for semantic search in memory files
- Register new component types in ComponentEnum and update imports
- Add constants for default host, port, and truncation limits
- Create BaseService abstract base class for service implementations
- Implement BaseStep with component accessors and lifecycle management
- Add proper __all__ exports for all new modules and components
2026-04-16 20:21:04 +08:00

346 lines
15 KiB
Python

"""Base embedding model with caching, batching, and retry support."""
import asyncio
import hashlib
import json
import time
from abc import abstractmethod
from collections import OrderedDict
from pathlib import Path
from ..base_component import BaseComponent
from ...enumeration import ComponentEnum
from ...schema import BaseNode
class BaseEmbeddingModel(BaseComponent):
"""Abstract base class for embedding models with LRU cache and retry logic.
Provides:
- LRU in-memory cache with disk persistence (JSONL)
- Automatic text truncation to max_input_length
- Retry logic with exponential backoff
- Batch embedding support
"""
component_type = ComponentEnum.EMBEDDING_MODEL
def __init__(
self,
api_key: str | None = None,
base_url: str | None = None,
model_name: str = "",
dimensions: int = 1024,
use_dimensions: bool = False,
max_batch_size: int = 10,
max_retries: int = 3,
raise_exception: bool = True,
max_input_length: int = 8192,
cache_dir: str | Path = ".reme",
max_cache_size: int = 2000,
enable_cache: bool = True,
encoding: str = "utf-8",
**kwargs,
):
"""Initialize embedding model configuration.
Args:
api_key: API key for the embedding service.
base_url: Base URL for the embedding service.
model_name: Name of the embedding model.
dimensions: Vector dimensions.
use_dimensions: Whether to pass dimensions parameter to API.
max_batch_size: Maximum batch size for embedding requests.
max_retries: Maximum retry attempts on failure.
raise_exception: Whether to raise exceptions on failure.
max_input_length: Maximum input text length.
cache_dir: Directory for cache storage.
max_cache_size: Maximum LRU cache size.
enable_cache: Whether to enable caching.
encoding: Text encoding for cache file operations.
"""
super().__init__(**kwargs)
self.api_key: str | None = api_key
self.base_url: str | None = base_url
self.model_name = model_name
self.dimensions = dimensions
self.use_dimensions = use_dimensions
self.max_batch_size = max_batch_size
self.max_retries = max_retries
self.raise_exception = raise_exception
self.max_input_length = max_input_length
self.cache_dir = cache_dir
self.max_cache_size = max_cache_size
self.enable_cache = enable_cache
self.encoding = encoding
self._embedding_cache: OrderedDict[str, list[float]] = OrderedDict()
self._cache_hits = 0
self._cache_misses = 0
self.cache_path: Path = Path(self.cache_dir)
def _truncate_text(self, text: str) -> str:
"""Truncate text to max_input_length."""
return text[: self.max_input_length] if len(text) > self.max_input_length else text
def _validate_and_adjust_embedding(self, embedding: list[float]) -> list[float]:
"""Adjust embedding dimensions to match expected dimensions."""
actual_len = len(embedding)
if actual_len == self.dimensions:
return embedding
if actual_len < self.dimensions:
self.logger.warning(
f"[ACTUAL_EMB_LENGTH] Embedding {actual_len} < expected {self.dimensions}, padding with zeros",
)
return embedding + [0.0] * (self.dimensions - actual_len)
self.logger.warning(
f"[ACTUAL_EMB_LENGTH] Embedding {actual_len} > expected {self.dimensions}, truncating",
)
return embedding[: self.dimensions]
def _get_cache_key(self, text: str) -> str:
"""Generate cache key from text + model_name + dimensions."""
cache_string = f"{text}|{self.model_name}|{self.dimensions}"
return hashlib.sha256(cache_string.encode(self.encoding)).hexdigest()
def _get_cache_file_path(self) -> Path:
"""Return path to the cache JSONL file."""
return self.cache_path / "embedding_cache.jsonl"
def _load_cache(self) -> None:
"""Load embedding cache from disk (JSONL format)."""
if not self.enable_cache:
return
self.cache_path.mkdir(parents=True, exist_ok=True)
cache_file = self._get_cache_file_path()
if not cache_file.exists():
self.logger.info(f"No cache file at {cache_file}, starting empty")
return
try:
load_start = time.time()
with open(cache_file, "r", encoding=self.encoding) as f:
lines = f.readlines()
loaded_count = 0
for line in reversed(lines):
line = line.strip()
if not line:
continue
try:
data = json.loads(line)
except json.JSONDecodeError as e:
self.logger.warning(f"Failed to parse cache line: {e}")
continue
if not data:
continue
cache_key, embedding = next(iter(data.items()))
if cache_key and embedding and isinstance(embedding, list):
if cache_key in self._embedding_cache:
continue
if len(embedding) != self.dimensions:
self.logger.warning(
f"Cache dimension mismatch for {cache_key}: "
f"expected {self.dimensions}, got {len(embedding)}",
)
continue
if len(self._embedding_cache) >= self.max_cache_size:
self.logger.info(f"Cache limit reached ({self.max_cache_size}), loaded {loaded_count}")
break
self._embedding_cache[cache_key] = embedding
loaded_count += 1
self.logger.info(f"Loaded {loaded_count} embeddings from {cache_file} in {time.time() - load_start:.2f}s")
except Exception as e:
self.logger.error(f"Failed to load cache from {cache_file}: {e}, deleting file")
try:
cache_file.unlink()
except Exception as del_e:
self.logger.error(f"Failed to delete cache file: {del_e}")
def _save_cache(self) -> None:
"""Save embedding cache to disk (JSONL format)."""
if not self.enable_cache or not self._embedding_cache:
return
cache_file = self._get_cache_file_path()
try:
with open(cache_file, "w", encoding=self.encoding) as f:
for cache_key, embedding in self._embedding_cache.items():
if len(embedding) != self.dimensions:
self.logger.warning(f"Cache dimension mismatch for {cache_key}")
continue
f.write(json.dumps({cache_key: embedding}, ensure_ascii=False) + "\n")
self.logger.info(f"Saved {len(self._embedding_cache)} embeddings to {cache_file}")
except Exception as e:
self.logger.error(f"Failed to save cache to {cache_file}: {e}")
def _get_from_cache(self, text: str) -> list[float] | None:
"""Retrieve embedding from cache if available."""
if not self.enable_cache:
return None
cache_key = self._get_cache_key(text)
if cache_key not in self._embedding_cache:
self._cache_misses += 1
return None
embeddings = self._embedding_cache[cache_key]
if len(embeddings) != self.dimensions:
self.logger.warning("Cached embedding dimension mismatch, removing entry")
del self._embedding_cache[cache_key]
self._cache_misses += 1
return None
self._embedding_cache.move_to_end(cache_key)
self._cache_hits += 1
preview = text[:50] + "..." if len(text) > 50 else text
self.logger.info(f"Cache hit: {preview} (hits: {self._cache_hits}, misses: {self._cache_misses})")
return embeddings
def _put_to_cache(self, text: str, embedding: list[float]) -> None:
"""Store embedding in cache with LRU eviction."""
if not self.enable_cache or self.max_cache_size <= 0:
return
cache_key = self._get_cache_key(text)
if len(embedding) != self.dimensions:
self.logger.warning(f"[PUT_TO_CACHE] Dimension mismatch for {cache_key}")
return
if len(self._embedding_cache) >= self.max_cache_size and cache_key not in self._embedding_cache:
self._embedding_cache.popitem(last=False)
self._embedding_cache[cache_key] = embedding
self._embedding_cache.move_to_end(cache_key)
def get_cache_stats(self) -> dict[str, int | float]:
"""Return cache statistics: size, hits, misses, hit_rate."""
total = self._cache_hits + self._cache_misses
hit_rate = self._cache_hits / total if total > 0 else 0.0
return {
"cache_size": len(self._embedding_cache),
"max_cache_size": self.max_cache_size,
"cache_hits": self._cache_hits,
"cache_misses": self._cache_misses,
"hit_rate": hit_rate,
}
def clear_cache(self) -> None:
"""Clear in-memory cache and reset statistics."""
self._embedding_cache.clear()
self._cache_hits = 0
self._cache_misses = 0
@abstractmethod
async def _get_embeddings(self, input_text: list[str], **kwargs) -> list[list[float]]:
"""Fetch embeddings for a batch of texts. Override in subclasses."""
async def get_embedding(self, input_text: str, **kwargs) -> list[float]:
"""Get embedding for a single text with cache and retry."""
truncated_text = self._truncate_text(input_text)
cached = self._get_from_cache(truncated_text)
if cached is not None:
return cached
for retry in range(self.max_retries):
try:
result = await self._get_embeddings([truncated_text], **kwargs)
if result and len(result) == 1:
embedding = self._validate_and_adjust_embedding(result[0])
self._put_to_cache(truncated_text, embedding)
return embedding
self.logger.warning(
f"Model {self.model_name} returned {len(result) if result else 0} results, expected 1",
)
if retry == self.max_retries - 1:
if self.raise_exception:
raise RuntimeError("Embedding API returned empty result")
return []
await asyncio.sleep(retry + 1)
except Exception as e:
self.logger.error(f"Model {self.model_name} failed: {e}")
if retry == self.max_retries - 1:
if self.raise_exception:
raise
return []
await asyncio.sleep(retry + 1)
return []
async def get_embeddings(self, input_text: list[str], **kwargs) -> list[list[float]]:
"""Get embeddings for multiple texts with cache and batching."""
truncated_texts = [self._truncate_text(t) for t in input_text]
results: list[list[float] | None] = [None] * len(truncated_texts)
texts_to_compute: list[tuple[int, str]] = []
for idx, text in enumerate(truncated_texts):
cached = self._get_from_cache(text)
if cached is not None:
results[idx] = cached
else:
texts_to_compute.append((idx, text))
if texts_to_compute:
uncached_texts = [text for _, text in texts_to_compute]
for i in range(0, len(uncached_texts), self.max_batch_size):
batch_texts = uncached_texts[i : i + self.max_batch_size]
batch_indices = [idx for idx, _ in texts_to_compute[i : i + self.max_batch_size]]
for retry in range(self.max_retries):
try:
batch_embeddings = await self._get_embeddings(batch_texts, **kwargs)
if batch_embeddings and len(batch_embeddings) == len(batch_texts):
for orig_idx, text, embedding in zip(batch_indices, batch_texts, batch_embeddings):
adjusted = self._validate_and_adjust_embedding(embedding)
results[orig_idx] = adjusted
self._put_to_cache(text, adjusted)
break
self.logger.warning(
f"Batch returned {len(batch_embeddings) if batch_embeddings else 0} "
f"results for {len(batch_texts)} inputs",
)
if retry == self.max_retries - 1:
if self.raise_exception:
raise RuntimeError(f"Batch embedding failed after {self.max_retries} retries")
for orig_idx in batch_indices:
if results[orig_idx] is None:
results[orig_idx] = []
else:
await asyncio.sleep(retry + 1)
except Exception as e:
self.logger.error(f"Model {self.model_name} batch failed: {e}")
if retry == self.max_retries - 1:
if self.raise_exception:
raise
for orig_idx in batch_indices:
if results[orig_idx] is None:
results[orig_idx] = []
else:
await asyncio.sleep(retry + 1)
return [r if r is not None else [] for r in results]
async def get_node_embeddings(self, nodes: list[BaseNode], **kwargs) -> list[BaseNode]:
"""Get embeddings for a list of nodes and assign to node.embedding."""
texts = [node.text for node in nodes]
embeddings = await self.get_embeddings(texts, **kwargs)
if len(embeddings) == len(nodes):
for node, vec in zip(nodes, embeddings):
node.embedding = vec
else:
self.logger.warning(f"Mismatch: {len(embeddings)} vectors for {len(nodes)} nodes, skipping assignment")
return nodes
async def _start(self, app_context=None) -> None:
"""Load cache on start."""
self._load_cache()
async def _close(self) -> None:
"""Save cache on close."""
self._save_cache()