File size: 7,513 Bytes
932bc69
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
"""
Prepare data for speculator training

Accepted inputs contain responses produced by the target model, either as
natural-language conversations or as speculator-format ``input_ids`` and
``loss_mask`` rows. For natural-language input this command:

1. Uses the target model's vLLM endpoint to render each conversation
2. Derives a loss mask from each assistant-turn boundary
3. Records token frequency statistics

Rendering converts an existing on-policy conversation into speculator format.
It does not generate responses or make an arbitrary conversation on-policy.

The output of this command is:
1. Processed dataset ready for online training or offline datagen in output_dir
2. Token frequency statistics file at token_freq_path

Preprocessing will be skipped if the dataset already exists at the output directory.
Token frequencies are saved in the output directory by default.

Usage::

    speculators prepare-data \\
        --model meta-llama/Llama-3.1-8B-Instruct \\
        --data ./on_policy_conversations.jsonl \\
        --render-endpoint http://localhost:8000 \\
        --output ./training_data \\
        --max-samples 5000
"""

import logging
import shutil
from pathlib import Path
from typing import Annotated

import typer

from speculators.data_generation.logging_utils import PipelineLogger
from speculators.data_generation.preprocessing import (
    default_preprocessing_workers,
    load_and_preprocess_dataset,
)

log = PipelineLogger(__name__)


PREPARE_DATA_OVERWRITE_ALLOWED_FILES = {
    "dataset_info.json",
    "state.json",
    "token_freq.pt",
}


def assert_safe_to_overwrite(output: Path, token_freq_path: Path) -> None:
    """Refuse to ``--overwrite`` a directory holding non-artifact files.

    Guards against pointing ``--output`` at a directory with unrelated user files
    and wiping it: only prepare-data's own outputs (``.arrow`` shards, dataset
    metadata, and the token frequency file) may be deleted.
    """
    unexpected_paths = []
    resolved_token_freq_path = token_freq_path.resolve()
    for path in output.iterdir():
        if path.is_file() and (
            path.suffix == ".arrow"
            or path.name in PREPARE_DATA_OVERWRITE_ALLOWED_FILES
            or path.resolve() == resolved_token_freq_path
        ):
            continue
        unexpected_paths.append(path)

    if unexpected_paths:
        formatted_paths = ", ".join(str(path) for path in unexpected_paths)
        raise ValueError(
            "--overwrite would delete files that do not look like prepare-data "
            f"artifacts: {formatted_paths}. Remove them manually or choose a "
            "different --output directory."
        )


def prepare_data(
    model: Annotated[
        str,
        typer.Option(help="HuggingFace model ID or local path for target model"),
    ],
    data: Annotated[
        list[str],
        typer.Option("--data", help="Path to training data (repeatable)"),
    ],
    output: Annotated[
        str,
        typer.Option(help="Directory to save output dataset"),
    ] = "./output",
    seq_length: Annotated[
        int,
        typer.Option(help="Maximum sequence length for preprocessing and model"),
    ] = 8192,
    max_samples: Annotated[
        int | None,
        typer.Option(help="Maximum number of samples to process"),
    ] = None,
    token_freq_path: Annotated[
        str | None,
        typer.Option(
            help="Path to save token frequency distribution",
        ),
    ] = None,
    render_endpoint: Annotated[
        str | None,
        typer.Option(
            help=(
                "Base URL of a running vLLM server (e.g. http://localhost:8000). "
                "Required unless every --data input already contains input_ids "
                "and loss_mask."
            ),
        ),
    ] = None,
    seed: Annotated[
        int,
        typer.Option(help="Random seed"),
    ] = 0,
    num_preprocessing_workers: Annotated[
        int | None,
        typer.Option(
            help=(
                "Number of CPU processes for dataset preprocessing. Each one "
                "blocks on a single render call at a time, so this is also the "
                "render concurrency. Defaults to a shared render CPU budget using "
                "75% of available CPUs, with a maximum of 128."
            ),
        ),
    ] = None,
    minimum_valid_tokens: Annotated[
        int | None,
        typer.Option(
            help=(
                "Drop samples whose loss mask contains fewer than this many "
                "trainable tokens."
            ),
        ),
    ] = None,
    overwrite: Annotated[
        bool,
        typer.Option(
            "--overwrite",
            help="Forcibly rerun. Deletes existing content in output dir",
        ),
    ] = False,
    allow_empty_output: Annotated[
        bool,
        typer.Option(
            "--allow-empty-output",
            help=(
                "Allow writing an empty preprocessed dataset. By default raises "
                "when normalization or filtering removes every sample."
            ),
        ),
    ] = False,
    trust_remote_code: Annotated[
        bool,
        typer.Option(
            "--trust-remote-code",
            help=(
                "Allow executing code from HF Hub when loading the target "
                "model's processor."
            ),
        ),
    ] = False,
) -> None:
    """Preprocess a dataset for speculator training.

    Tokenizes each sample, produces loss/assistant masks, and records token
    frequency statistics. Output is a HuggingFace dataset ready for online
    training or offline data generation.
    """
    logging.basicConfig(
        level=logging.INFO,
        format="%(asctime)s - %(name)s - %(levelname)s - %(message)s",
    )
    log.section("Preparing data")
    log.config(
        {
            "Target Model": model,
            "Dataset": data,
            "Output Dir": output,
        }
    )

    output_path = Path(output)
    resolved_token_freq_path = (
        output_path / "token_freq.pt"
        if token_freq_path is None
        else Path(token_freq_path)
    )

    if output_path.exists():
        if not overwrite and list(output_path.glob("*.arrow")):
            log.warning(
                "Dataset files already exist in output directory, skipping "
                "preprocessing. To overwrite existing files use --overwrite."
            )
            raise typer.Exit
        if overwrite:
            assert_safe_to_overwrite(output_path, resolved_token_freq_path)
            log.warning(f"Removing existing output directory: {output_path}")
            shutil.rmtree(output_path)
            output_path.mkdir(parents=True)
    else:
        output_path.mkdir(parents=True)

    dataset, _ = load_and_preprocess_dataset(
        target_model_path=model,
        train_data_paths=data,
        seq_length=seq_length,
        build_dataset_num_proc=(
            num_preprocessing_workers
            if num_preprocessing_workers is not None
            else default_preprocessing_workers()
        ),
        seed=seed,
        max_samples=max_samples,
        token_freq_path=resolved_token_freq_path,
        render_endpoint=render_endpoint,
        minimum_valid_tokens=minimum_valid_tokens,
        allow_empty_output=allow_empty_output,
        trust_remote_code=trust_remote_code,
    )

    log.info("Done preparing data")
    log.section(f"Writing dataset to {output}")
    dataset.save_to_disk(output)