Files
AstrAI/astrai/tokenize/tokenizer.py
T
ViperEkura fc47319240 refactor: simplify BaseFactory and separate ModelFactory from AutoModel
- Extract _resolve_base_type and _validate_component as module-level helpers
- Replace ForwardRef._evaluate private API with eval in module namespace
- Remove broad except Exception in __init_subclass__, _component_base always set
- Replace direct _entries mutation in strategy.py with register() call form
- Remove dead TOKENIZER_CLASSES registry from AutoTokenizer
- Extract ModelFactory(BaseFactory[nn.Module]) as pure factory
- AutoModel now inherits only nn.Module, no factory state
- Move @AutoModel.register to @ModelFactory.register in transformer.py and encoder.py
2026-07-30 09:38:20 +08:00

290 lines
9.9 KiB
Python

"""
Tokenizer module with implementation and auto-loading support.
"""
import json
from pathlib import Path
from typing import Dict, List, Optional, Union
from tokenizers import Tokenizer
from astrai.tokenize.chat_template import ChatTemplate
Message = Dict[str, str]
"""Single chat message with ``role`` and ``content`` keys."""
Messages = List[Message]
"""Single conversation — a list of messages."""
class AutoTokenizer:
"""Base tokenizer class with automatic loading support"""
def __init__(
self,
path: Optional[Union[str, Path]] = None,
special_token_map: Optional[Dict[str, str]] = None,
chat_template: Optional[str] = None,
):
self._tokenizer: Tokenizer = None
self._chat_template: Optional[ChatTemplate] = None
self._special_token_map: Optional[Dict] = special_token_map or {}
if chat_template:
self.set_chat_template(chat_template)
if path:
self.load(path)
def load(self, path: Union[str, Path]):
"""Load tokenizer from directory."""
path = Path(path)
tokenizer_file = path / "tokenizer.json"
config_file = path / "tokenizer_config.json"
self._tokenizer = Tokenizer.from_file(str(tokenizer_file))
if config_file.exists():
with open(config_file, "r", encoding="utf-8") as f:
config = json.load(f)
if "special_tokens" in config:
self._special_token_map.update(config["special_tokens"])
# Load chat template from config
if "chat_template" in config:
self.set_chat_template(config["chat_template"])
@classmethod
def from_pretrained(cls, path: Union[str, Path]) -> "AutoTokenizer":
"""Load tokenizer from pretrained directory.
Raises:
FileNotFoundError: If tokenizer.json is missing.
RuntimeError: If tokenizer failed to initialize.
"""
path = Path(path)
tokenizer_file = path / "tokenizer.json"
if not tokenizer_file.exists():
raise FileNotFoundError(
f"Tokenizer file not found: {tokenizer_file}. "
"A valid tokenizer.json is required."
)
instance = cls(path)
if instance._tokenizer is None:
raise RuntimeError(
f"Failed to load tokenizer from {path}. "
"The tokenizer.json may be corrupted or incompatible."
)
return instance
def save_pretrained(self, save_path: str):
"""
Save tokenizer to pretrained directory.
Args:
save_path: Path to save the tokenizer
"""
if self._tokenizer is None:
raise RuntimeError(
"Tokenizer not initialized. Load or create a tokenizer first."
)
save_path = Path(save_path)
save_path.mkdir(parents=True, exist_ok=True)
# Save tokenizer
self._tokenizer.save(str(save_path / "tokenizer.json"))
# Save tokenizer config
config = {}
if self._special_token_map is not None:
config["special_tokens"] = self._special_token_map
if self._chat_template is not None:
config["chat_template"] = self._chat_template.template_str
with open(save_path / "tokenizer_config.json", "w", encoding="utf-8") as f:
json.dump(config, f, ensure_ascii=False, indent=2)
def encode(
self,
tokens: Union[str, List[str]],
out_ids: bool = True,
is_pretokenized: bool = False,
add_special_tokens: bool = True,
) -> List:
"""Encode text to token IDs.
Accepts both single strings and batches:
- ``encode("hello")`` → ``[123, 456]``
- ``encode(["hello", "world"])`` → ``[[123, 456], [789]]``
Batches are tokenised in parallel via the Rust backend's
``encode_batch`` (uses all available CPU cores).
"""
if self._tokenizer is None:
raise RuntimeError(
"Tokenizer not initialized. Load or create a tokenizer first."
)
if isinstance(tokens, str):
encoded = self._tokenizer.encode(
tokens,
is_pretokenized=is_pretokenized,
add_special_tokens=add_special_tokens,
)
return encoded.ids if out_ids else encoded.tokens
encoded_list = self._tokenizer.encode_batch(
tokens,
is_pretokenized=is_pretokenized,
add_special_tokens=add_special_tokens,
)
return [encoded.ids if out_ids else encoded.tokens for encoded in encoded_list]
def decode(self, tokens: List[int], skip_special_tokens: bool = True) -> str:
"""Decode token IDs to text."""
if self._tokenizer is None:
raise RuntimeError(
"Tokenizer not initialized. Load or create a tokenizer first."
)
return self._tokenizer.decode(tokens, skip_special_tokens=skip_special_tokens)
def __len__(self) -> int:
if self._tokenizer is None:
return 0
return self._tokenizer.get_vocab_size()
def __getattr__(self, key: str):
"""
Dynamically intercept special token attribute access.
Supports three forms:
- tokenizer.bos_token → returns string
- tokenizer.bos_token_id → returns corresponding integer ID
- tokenizer.stop_ids → returns list of corresponding integer IDs for all special tokens
Internal/private attrs are not intercepted: during unpickle
``__dict__`` is empty, so probing ``self._special_token_map``
would recurse infinitely.
"""
if key.startswith("_"):
raise AttributeError(key)
# Handle stop_ids - return IDs for all special tokens
if key == "stop_ids":
stop_ids = []
if self._tokenizer is None:
return stop_ids
for val in self._special_token_map.values():
token_id = self._tokenizer.token_to_id(val)
if token_id is not None:
stop_ids.append(token_id)
return stop_ids
# Handle _id suffix (e.g., bos_token_id -> bos_token)
if key.endswith("_id"):
base_attr = key[:-3] # Remove "_id"
token_str = self._special_token_map.get(base_attr)
if token_str is None:
return None
if self._tokenizer is None:
raise RuntimeError("Tokenizer not loaded, cannot convert token to id.")
return self._tokenizer.token_to_id(token_str)
# Handle regular string attributes
if key in self._special_token_map:
return self._special_token_map.get(key)
# Other attributes trigger default AttributeError
raise AttributeError(f"'{type(self).__name__}' object has no attribute '{key}'")
@property
def vocab_size(self) -> int:
return len(self)
def set_chat_template(self, template: Union[str, ChatTemplate]):
"""
Set the chat template for the tokenizer.
Args:
template: Either a template name (str) registered in the global registry,
or a ChatTemplate instance, or a Jinja2 template string.
Raises:
KeyError: If template name is not registered.
"""
if isinstance(template, str):
self._chat_template = ChatTemplate.from_string(template)
elif isinstance(template, ChatTemplate):
self._chat_template = template
else:
raise ValueError("Invalid template type, must be str or ChatTemplate.")
def apply_chat_template(
self,
messages: Union[Messages, List[Messages]],
system_prompt: Optional[str] = None,
tokenize: bool = True,
add_generation_prompt: bool = True,
**kwargs,
) -> Union[str, List[int], List[str], List[List[int]]]:
"""Apply the chat template and optionally tokenize.
Accepts both single conversations and batches:
- ``apply_chat_template([msg1, msg2])`` → ``"..."`` or ``[ids]``
- ``apply_chat_template([[msg1, msg2], [msg3]])`` → ``["..", ".."]``
or ``[[ids], [ids]]``
Batches render each conversation list and tokenise all at once via
:meth:`encode` (``List[str]`` → Rust parallel ``encode_batch``).
Args:
messages: Single conversation (``Messages``) or batch of
conversations (``BatchMessages``).
system_prompt: Optional system prompt prepended (single mode only).
tokenize: Whether to return token IDs (True) or raw string (False).
add_generation_prompt: Whether to add the generation prompt.
**kwargs: Additional template variables.
Returns:
Single mode: ``str`` or ``List[int]``.
Batch mode: ``List[str]`` or ``List[List[int]]``.
"""
if self._chat_template is None:
raise RuntimeError(
"Chat template not set. Use set_chat_template() to set a template first."
)
is_batch = bool(messages) and isinstance(messages[0], list)
if is_batch:
rendered = [
self._chat_template.render(
messages=msgs,
add_generation_prompt=add_generation_prompt,
**kwargs,
)
for msgs in messages
]
if tokenize:
return self.encode(rendered) # List[str] → batch encode
return rendered
# Single conversation
if system_prompt:
messages = [{"role": "system", "content": system_prompt}] + list(messages)
rendered = self._chat_template.render(
messages=messages,
add_generation_prompt=add_generation_prompt,
**kwargs,
)
if tokenize:
return self.encode(rendered)
return rendered