refactor : 统一 SectionedMaskBuilder,支持可配置 dtype

- 三合一 MaskBuilder,移除 chat/instruction/text,统一为 sections 配置
- OutputConfig 增加 dtype 字段 (per-key,默认 int32)
- 移除 from __future__ import annotations
- 测试适配新配置格式
This commit is contained in:
2026-05-31 14:24:10 +08:00
parent 2a65c3314c
commit dbe5891201
5 changed files with 330 additions and 206 deletions
+102 -104
View File
@@ -1,13 +1,11 @@
"""Mask building strategies for preprocessing pipeline.
Each builder knows how to tokenize one input format and construct
the loss_mask according to declarative mask rules from the config.
The single :class:`SectionedMaskBuilder` handles all input formats
via declarative ``input.sections`` config.
"""
from __future__ import annotations
from abc import ABC, abstractmethod
from typing import List, Optional
from typing import Optional
from astrai.factory import BaseFactory
@@ -40,122 +38,122 @@ def _extract_domain(item: dict, domain_key: Optional[str]) -> str:
return val if isinstance(val, str) else "__default__"
@MaskBuilderFactory.register("chat")
class ChatMaskBuilder(BaseMaskBuilder):
"""Mask by role via message-level tokenisation with role-span tracking.
def _resolve_action(action: str, role: str, config) -> str:
"""Resolve action to "train" or "mask".
For each message, renders the chat template for that single message,
encodes individually, and records its token span + role action.
The concatenated sequence receives a loss_mask built from span rules.
- ``"train"`` / ``"mask"`` → literal
- ``"$role"`` → look up ``role`` in ``config.mask``, fall back to ``config.mask_default``
"""
if action == "$role":
return config.mask.get(role, config.mask_default)
return action
@MaskBuilderFactory.register("sectioned")
class SectionedMaskBuilder(BaseMaskBuilder):
"""Config-driven builder: iterates over ``input.sections`` in order.
Each section specifies a JSONL field + mask action.
Section spec::
{
"field": "messages", # JSONL key
"action": "$role", # "train" | "mask" | "$role"
"template": true, # apply chat_template per message (optional)
"add_special_tokens": false # override encode flag (optional)
}
Example configs::
# Chat
{"input": {"sections": [
{"field": "messages", "action": "$role", "template": true}
]}}
# Instruction
{"input": {"sections": [
{"field": "prompt", "action": "mask", "add_special_tokens": true},
{"field": "response", "action": "train"}
]}}
# Text
{"input": {"sections": [
{"field": "text", "action": "train"}
]}}
"""
def build(self, item: dict, config, tokenizer) -> Optional[dict]:
messages = item.get(config.input.messages_key)
if not isinstance(messages, list) or not messages:
sections = config.input.sections
if not sections:
return None
all_ids: List[int] = []
spans: List[tuple] = []
all_ids: list[int] = []
loss_mask: list[int] = []
if tokenizer.bos_token_id is not None:
has_template = any(s.get("template") for s in sections)
is_text_config = not has_template and all(
s["action"] == "train" for s in sections
)
if has_template and tokenizer.bos_token_id is not None:
all_ids.append(tokenizer.bos_token_id)
loss_mask.append(0)
for msg in messages:
role = msg.get("role", "")
action = config.mask.get(role, config.mask_default)
rendered = tokenizer.apply_chat_template(
[msg], tokenize=False, add_generation_prompt=False
first_section = True
for sec in sections:
field = sec["field"]
action = sec["action"]
use_template = sec.get("template", False)
add_special = sec.get(
"add_special_tokens", not use_template and first_section
)
ids = tokenizer.encode(rendered, add_special_tokens=False)
start = len(all_ids)
all_ids.extend(ids)
spans.append((start, len(all_ids), action))
if use_template:
messages = item.get(field)
if not isinstance(messages, list) or not messages:
continue
for msg in messages:
role = msg.get("role", "")
act = _resolve_action(action, role, config)
rendered = tokenizer.apply_chat_template(
[msg], tokenize=False, add_generation_prompt=False
)
ids = tokenizer.encode(rendered, add_special_tokens=False)
all_ids.extend(ids)
val = 1 if act == "train" else 0
loss_mask.extend([val] * len(ids))
else:
text = str(item.get(field, ""))
if not text.strip():
continue
if is_text_config:
pp = config.preprocessing
if pp.min_chars > 0 and len(text) < pp.min_chars:
continue
if len(text) > pp.max_chars:
continue
ids = tokenizer.encode(text, add_special_tokens=add_special)
all_ids.extend(ids)
val = 1 if action == "train" else 0
loss_mask.extend([val] * len(ids))
if len(all_ids) <= 1:
return None
first_section = False
max_len = config.preprocessing.max_seq_len
all_ids = all_ids[:max_len]
loss_mask = loss_mask[: len(all_ids)]
loss_mask = [0] * len(all_ids)
for start, end, action in spans:
if start >= len(all_ids):
break
e = min(end, len(all_ids))
if action == "train":
loss_mask[start:e] = [1] * (e - start)
if not all_ids:
return None
return {
if has_template and len(all_ids) <= 1:
return None
result: dict = {
"ids": all_ids,
"loss_mask": loss_mask,
"domain": _extract_domain(item, config.output.domain_key),
}
@MaskBuilderFactory.register("instruction")
class InstructionMaskBuilder(BaseMaskBuilder):
"""Mask by prompt / response field boundary.
Encodes prompt and response independently, then fills mask
according to ``prompt`` / ``response`` entries in the mask config.
"""
def build(self, item: dict, config, tokenizer) -> Optional[dict]:
prompt = str(item.get(config.input.prompt_key, ""))
response = str(item.get(config.input.response_key, ""))
if not prompt.strip() and not response.strip():
return None
prompt_ids = tokenizer.encode(prompt, add_special_tokens=True)
response_ids = tokenizer.encode(response, add_special_tokens=False)
max_len = config.preprocessing.max_seq_len
full_ids = (prompt_ids + response_ids)[:max_len]
prompt_action = config.mask.get("prompt", config.mask_default)
response_action = config.mask.get("response", config.mask_default)
p_len = min(len(prompt_ids), len(full_ids))
r_len = len(full_ids) - p_len
loss_mask = []
if prompt_action == "train":
loss_mask += [1] * p_len
else:
loss_mask += [0] * p_len
if response_action == "train":
loss_mask += [1] * r_len
else:
loss_mask += [0] * r_len
return {
"ids": full_ids,
"loss_mask": loss_mask,
"domain": _extract_domain(item, config.output.domain_key),
}
@MaskBuilderFactory.register("text")
class TextMaskBuilder(BaseMaskBuilder):
"""Plain tokenisation — no mask, used for pre-training data."""
def build(self, item: dict, config, tokenizer) -> Optional[dict]:
text = item.get(config.input.text_key, "")
if not isinstance(text, str) or not text.strip():
return None
pp = config.preprocessing
if not (pp.min_chars <= len(text) <= pp.max_chars):
return None
ids = tokenizer.encode(text, add_special_tokens=True)
ids = ids[: pp.max_seq_len]
return {
"ids": ids,
"domain": _extract_domain(item, config.output.domain_key),
}
if not all(m == 1 for m in loss_mask):
result["loss_mask"] = loss_mask
return result