Generate: basic token streaming (#22449)

* haha tokens go brrrr
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Joao Gante 2023-03-30 12:00:12 +01:00 committed by GitHub
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@ -139,6 +139,29 @@ one for summarization with beam search). You must have the right Hub permissions
['Les fichiers de configuration sont faciles à utiliser !']
```
## Streaming
The `generate()` supports streaming, through its `streamer` input. The `streamer` input is compatible any instance
from a class that has the following methods: `put()` and `end()`. Internally, `put()` is used to push new tokens and
`end()` is used to flag the end of text generation.
In practice, you can craft your own streaming class for all sorts of purposes! We also have basic streaming classes
ready for you to use. For example, you can use the [`TextStreamer`] class to stream the output of `generate()` into
your screen, one word at a time:
```python
>>> from transformers import AutoModelForCausalLM, AutoTokenizer, TextStreamer
>>> tok = AutoTokenizer.from_pretrained("gpt2")
>>> model = AutoModelForCausalLM.from_pretrained("gpt2")
>>> inputs = tok(["An increasing sequence: one,"], return_tensors="pt")
>>> streamer = TextStreamer(tok)
>>> # Despite returning the usual output, the streamer will also print the generated text to stdout.
>>> _ = model.generate(**inputs, streamer=streamer, max_new_tokens=20)
An increasing sequence: one, two, three, four, five, six, seven, eight, nine, ten, eleven,
```
## Decoding strategies
Certain combinations of the `generate()` parameters, and ultimately `generation_config`, can be used to enable specific

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@ -265,3 +265,7 @@ A [`Constraint`] can be used to force the generation to include specific tokens
[[autodoc]] top_k_top_p_filtering
[[autodoc]] tf_top_k_top_p_filtering
## Streamers
[[autodoc]] TextStreamer

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@ -24,7 +24,8 @@ of the generation method.
To learn how to inspect a model's generation configuration, what are the defaults, how to change the parameters ad hoc,
and how to create and save a customized generation configuration, refer to the
[text generation strategies guide](../generation_strategies).
[text generation strategies guide](../generation_strategies). The guide also explains how to use related features,
like token streaming.
## GenerationConfig

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@ -96,7 +96,7 @@ _import_structure = {
"feature_extraction_sequence_utils": ["SequenceFeatureExtractor"],
"feature_extraction_utils": ["BatchFeature", "FeatureExtractionMixin"],
"file_utils": [],
"generation": ["GenerationConfig"],
"generation": ["GenerationConfig", "TextStreamer"],
"hf_argparser": ["HfArgumentParser"],
"image_transforms": [],
"integrations": [
@ -3769,7 +3769,7 @@ if TYPE_CHECKING:
from .feature_extraction_utils import BatchFeature, FeatureExtractionMixin
# Generation
from .generation import GenerationConfig
from .generation import GenerationConfig, TextStreamer
from .hf_argparser import HfArgumentParser
# Integrations

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@ -17,8 +17,7 @@ from typing import TYPE_CHECKING
from ..utils import OptionalDependencyNotAvailable, _LazyModule, is_flax_available, is_tf_available, is_torch_available
_import_structure = {"configuration_utils": ["GenerationConfig"]}
_import_structure = {"configuration_utils": ["GenerationConfig"], "streamers": ["TextStreamer"]}
try:
if not is_torch_available():
@ -150,6 +149,7 @@ else:
if TYPE_CHECKING:
from .configuration_utils import GenerationConfig
from .streamers import TextStreamer
try:
if not is_torch_available():

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@ -0,0 +1,104 @@
# coding=utf-8
# Copyright 2023 The HuggingFace Inc. team.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from typing import TYPE_CHECKING
if TYPE_CHECKING:
from ..models.auto import AutoTokenizer
class BaseStreamer:
"""
Base class from which `.generate()` streamers should inherit.
"""
def put(self, value):
"""Function that is called by `.generate()` to push new tokens"""
raise NotImplementedError()
def end(self):
"""Function that is called by `.generate()` to signal the end of generation"""
raise NotImplementedError()
class TextStreamer(BaseStreamer):
"""
Simple text streamer that prints the token(s) to stdout as soon as entire words are formed.
Parameters:
tokenizer (`AutoTokenizer`):
The tokenized used to decode the tokens.
Examples:
```python
>>> from transformers import AutoModelForCausalLM, AutoTokenizer, TextStreamer
>>> tok = AutoTokenizer.from_pretrained("gpt2")
>>> model = AutoModelForCausalLM.from_pretrained("gpt2")
>>> inputs = tok(["An increasing sequence: one,"], return_tensors="pt")
>>> streamer = TextStreamer(tok)
>>> # Despite returning the usual output, the streamer will also print the generated text to stdout.
>>> _ = model.generate(**inputs, streamer=streamer, max_new_tokens=20)
An increasing sequence: one, two, three, four, five, six, seven, eight, nine, ten, eleven,
```
"""
def __init__(self, tokenizer: "AutoTokenizer"):
self.tokenizer = tokenizer
self.token_cache = []
self.print_len = 0
def put(self, value):
"""
Recives tokens, decodes them, and prints them to stdout as soon as they form entire words.
"""
if len(value.shape) > 1 and value.shape[0] > 1:
raise ValueError("TextStreamer only supports batch size 1")
elif len(value.shape) > 1:
value = value[0]
# Add the new token to the cache and decodes the entire thing.
self.token_cache.extend(value.tolist())
text = self.tokenizer.decode(self.token_cache)
# After symbol for a new line, we flush the cache.
if text.endswith("\n"):
printable_text = text[self.print_len :]
self.token_cache = []
self.print_len = 0
# Otherwise, prints until the last space char (simple heuristic to avoid printing incomplete words,
# which may change with the subsequent token -- there are probably smarter ways to do this!)
else:
printable_text = text[self.print_len : text.rfind(" ") + 1]
self.print_len += len(printable_text)
print(printable_text, flush=True, end="")
def end(self):
"""Flushes any remaining cache and prints a newline to stdout."""
# Flush the cache, if it exists
if len(self.token_cache) > 0:
text = self.tokenizer.decode(self.token_cache)
printable_text = text[self.print_len :]
self.token_cache = []
self.print_len = 0
else:
printable_text = ""
# Print a newline (and the remaining text, if any)
print(printable_text, flush=True)

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@ -18,7 +18,7 @@ import copy
import inspect
import warnings
from dataclasses import dataclass
from typing import Any, Callable, Dict, List, Optional, Tuple, Union
from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, Tuple, Union
import torch
import torch.distributed as dist
@ -72,6 +72,10 @@ from .stopping_criteria import (
)
if TYPE_CHECKING:
from .streamers import BaseStreamer
logger = logging.get_logger(__name__)
@ -1116,6 +1120,7 @@ class GenerationMixin:
stopping_criteria: Optional[StoppingCriteriaList] = None,
prefix_allowed_tokens_fn: Optional[Callable[[int, torch.Tensor], List[int]]] = None,
synced_gpus: Optional[bool] = None,
streamer: Optional["BaseStreamer"] = None,
**kwargs,
) -> Union[GenerateOutput, torch.LongTensor]:
r"""
@ -1165,6 +1170,9 @@ class GenerationMixin:
Whether to continue running the while loop until max_length. Unless overridden this flag will be set to
`True` under DeepSpeed ZeRO Stage 3 multiple GPUs environment to avoid hanging if one GPU finished
generating before other GPUs. Otherwise it'll be set to `False`.
streamer (`BaseStreamer`, *optional*):
Streamer object that will be used to stream the generated sequences. Generated tokens are passed
through `streamer.put(token_ids)` and the streamer is responsible for any further processing.
kwargs:
Ad hoc parametrization of `generate_config` and/or additional model-specific kwargs that will be
@ -1295,6 +1303,9 @@ class GenerationMixin:
else:
input_ids = inputs_tensor if model_input_name == "input_ids" else model_kwargs.pop("input_ids")
if streamer is not None:
streamer.put(input_ids.cpu())
# 6. Prepare `max_length` depending on other stopping criteria.
input_ids_seq_length = input_ids.shape[-1]
has_default_max_length = kwargs.get("max_length") is None and generation_config.max_length is not None
@ -1335,7 +1346,8 @@ class GenerationMixin:
)
is_contrastive_search_gen_mode = (
generation_config.top_k is not None
(generation_config.num_beams == 1)
and generation_config.top_k is not None
and generation_config.top_k > 1
and generation_config.do_sample is False
and generation_config.penalty_alpha is not None
@ -1384,6 +1396,11 @@ class GenerationMixin:
"Diverse beam search cannot be used in sampling mode. Make sure that `do_sample` is set to `False`."
)
if streamer is not None and (generation_config.num_beams > 1):
raise ValueError(
"`streamer` cannot be used with beam search (yet!). Make sure that `num_beams` is set to 1."
)
if self.device.type != input_ids.device.type:
warnings.warn(
"You are calling .generate() with the `input_ids` being on a device type different"
@ -1426,6 +1443,7 @@ class GenerationMixin:
output_scores=generation_config.output_scores,
return_dict_in_generate=generation_config.return_dict_in_generate,
synced_gpus=synced_gpus,
streamer=streamer,
**model_kwargs,
)
@ -1447,6 +1465,7 @@ class GenerationMixin:
output_scores=generation_config.output_scores,
return_dict_in_generate=generation_config.return_dict_in_generate,
synced_gpus=synced_gpus,
streamer=streamer,
**model_kwargs,
)
@ -1473,6 +1492,7 @@ class GenerationMixin:
output_scores=generation_config.output_scores,
return_dict_in_generate=generation_config.return_dict_in_generate,
synced_gpus=synced_gpus,
streamer=streamer,
**model_kwargs,
)
@ -1703,6 +1723,7 @@ class GenerationMixin:
output_scores: Optional[bool] = None,
return_dict_in_generate: Optional[bool] = None,
synced_gpus: Optional[bool] = False,
streamer: Optional["BaseStreamer"] = None,
**model_kwargs,
) -> Union[ContrastiveSearchOutput, torch.LongTensor]:
r"""
@ -1750,6 +1771,9 @@ class GenerationMixin:
Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple.
synced_gpus (`bool`, *optional*, defaults to `False`):
Whether to continue running the while loop until max_length (needed for ZeRO stage 3)
streamer (`BaseStreamer`, *optional*):
Streamer object that will be used to stream the generated sequences. Generated tokens are passed
through `streamer.put(token_ids)` and the streamer is responsible for any further processing.
model_kwargs:
Additional model specific keyword arguments will be forwarded to the `forward` function of the model.
If model is an encoder-decoder model the kwargs should include `encoder_outputs`.
@ -2010,6 +2034,8 @@ class GenerationMixin:
# update generated ids, model inputs, and length for next step
input_ids = torch.cat([input_ids, next_tokens[:, None]], dim=-1)
if streamer is not None:
streamer.put(next_tokens.cpu())
model_kwargs = self._update_model_kwargs_for_generation(
outputs, model_kwargs, is_encoder_decoder=self.config.is_encoder_decoder
)
@ -2027,6 +2053,9 @@ class GenerationMixin:
else:
this_peer_finished = True
if streamer is not None:
streamer.end()
if return_dict_in_generate:
if self.config.is_encoder_decoder:
return ContrastiveSearchEncoderDecoderOutput(
@ -2061,6 +2090,7 @@ class GenerationMixin:
output_scores: Optional[bool] = None,
return_dict_in_generate: Optional[bool] = None,
synced_gpus: Optional[bool] = False,
streamer: Optional["BaseStreamer"] = None,
**model_kwargs,
) -> Union[GreedySearchOutput, torch.LongTensor]:
r"""
@ -2105,6 +2135,9 @@ class GenerationMixin:
Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple.
synced_gpus (`bool`, *optional*, defaults to `False`):
Whether to continue running the while loop until max_length (needed for ZeRO stage 3)
streamer (`BaseStreamer`, *optional*):
Streamer object that will be used to stream the generated sequences. Generated tokens are passed
through `streamer.put(token_ids)` and the streamer is responsible for any further processing.
model_kwargs:
Additional model specific keyword arguments will be forwarded to the `forward` function of the model.
If model is an encoder-decoder model the kwargs should include `encoder_outputs`.
@ -2256,6 +2289,8 @@ class GenerationMixin:
# update generated ids, model inputs, and length for next step
input_ids = torch.cat([input_ids, next_tokens[:, None]], dim=-1)
if streamer is not None:
streamer.put(next_tokens.cpu())
model_kwargs = self._update_model_kwargs_for_generation(
outputs, model_kwargs, is_encoder_decoder=self.config.is_encoder_decoder
)
@ -2273,6 +2308,9 @@ class GenerationMixin:
else:
this_peer_finished = True
if streamer is not None:
streamer.end()
if return_dict_in_generate:
if self.config.is_encoder_decoder:
return GreedySearchEncoderDecoderOutput(
@ -2308,6 +2346,7 @@ class GenerationMixin:
output_scores: Optional[bool] = None,
return_dict_in_generate: Optional[bool] = None,
synced_gpus: Optional[bool] = False,
streamer: Optional["BaseStreamer"] = None,
**model_kwargs,
) -> Union[SampleOutput, torch.LongTensor]:
r"""
@ -2354,6 +2393,9 @@ class GenerationMixin:
Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple.
synced_gpus (`bool`, *optional*, defaults to `False`):
Whether to continue running the while loop until max_length (needed for ZeRO stage 3)
streamer (`BaseStreamer`, *optional*):
Streamer object that will be used to stream the generated sequences. Generated tokens are passed
through `streamer.put(token_ids)` and the streamer is responsible for any further processing.
model_kwargs:
Additional model specific kwargs will be forwarded to the `forward` function of the model. If model is
an encoder-decoder model the kwargs should include `encoder_outputs`.
@ -2525,6 +2567,8 @@ class GenerationMixin:
# update generated ids, model inputs, and length for next step
input_ids = torch.cat([input_ids, next_tokens[:, None]], dim=-1)
if streamer is not None:
streamer.put(next_tokens.cpu())
model_kwargs = self._update_model_kwargs_for_generation(
outputs, model_kwargs, is_encoder_decoder=self.config.is_encoder_decoder
)
@ -2542,6 +2586,9 @@ class GenerationMixin:
else:
this_peer_finished = True
if streamer is not None:
streamer.end()
if return_dict_in_generate:
if self.config.is_encoder_decoder:
return SampleEncoderDecoderOutput(

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@ -0,0 +1,44 @@
# coding=utf-8
# Copyright 2023 The HuggingFace Team Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a clone of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import unittest
from transformers import AutoTokenizer, TextStreamer, is_torch_available
from transformers.testing_utils import CaptureStdout, require_torch, torch_device
from ..test_modeling_common import ids_tensor
if is_torch_available():
from transformers import AutoModelForCausalLM
@require_torch
class StreamerTester(unittest.TestCase):
def test_text_streamer_stdout(self):
tokenizer = AutoTokenizer.from_pretrained("hf-internal-testing/tiny-random-gpt2")
model = AutoModelForCausalLM.from_pretrained("hf-internal-testing/tiny-random-gpt2").to(torch_device)
model.config.eos_token_id = -1
input_ids = ids_tensor((1, 5), vocab_size=model.config.vocab_size).to(torch_device)
greedy_ids = model.generate(input_ids, max_new_tokens=10, do_sample=False)
greedy_text = tokenizer.decode(greedy_ids[0])
with CaptureStdout() as cs:
streamer = TextStreamer(tokenizer)
model.generate(input_ids, max_new_tokens=10, do_sample=False, streamer=streamer)
# The greedy text should be printed to stdout, except for the final "\n" in the streamer
self.assertEqual(cs.out[:-1], greedy_text)