# Copyright 2025 The HuggingFace Team. All rights reserved.
#
# 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.
import copy
import json
import os
import platform
import string
import time
from argparse import ArgumentParser, Namespace
from dataclasses import dataclass, field
from threading import Thread
from typing import Optional
import yaml
from transformers.utils import is_rich_available, is_torch_available
from . import BaseTransformersCLICommand
if platform.system() != "Windows":
import pwd
if is_rich_available():
from rich.console import Console
from rich.live import Live
from rich.markdown import Markdown
if is_torch_available():
import torch
from transformers import AutoModelForCausalLM, AutoTokenizer, BitsAndBytesConfig, TextIteratorStreamer
ALLOWED_KEY_CHARS = set(string.ascii_letters + string.whitespace)
ALLOWED_VALUE_CHARS = set(
string.ascii_letters + string.digits + string.whitespace + r".!\"#$%&'()*+,\-/:<=>?@[]^_`{|}~"
)
HELP_STRING = """\
**TRANSFORMERS CHAT INTERFACE**
The chat interface is a simple tool to try out a chat model.
Besides talking to the model there are several commands:
- **help**: show this help message
- **clear**: clears the current conversation and start a new one
- **example {NAME}**: load example named `{NAME}` from the config and use it as the user input
- **set {SETTING_NAME}={SETTING_VALUE};**: change the system prompt or generation settings (multiple settings are separated by a ';').
- **reset**: same as clear but also resets the generation configs to defaults if they have been changed by **set**
- **save {SAVE_NAME} (optional)**: save the current chat and settings to file by default to `./chat_history/{MODEL_NAME}/chat_{DATETIME}.yaml` or `{SAVE_NAME}` if provided
- **exit**: closes the interface
"""
SUPPORTED_GENERATION_KWARGS = [
"max_new_tokens",
"do_sample",
"num_beams",
"temperature",
"top_p",
"top_k",
"repetition_penalty",
]
DEFAULT_EXAMPLES = {
"llama": {"text": "There is a Llama in my lawn, how can I get rid of it?"},
"code": {
"text": "Write a Python function that integrates any Python function f(x) numerically over an arbitrary interval [x_start, x_end]."
},
"helicopter": {"text": "How many helicopters can a human eat in one sitting?"},
"numbers": {"text": "Count to 10 but skip every number ending with an 'e'"},
"birds": {"text": "Why aren't birds real?"},
"socks": {"text": "Why is it important to eat socks after meditating?"},
}
def get_username():
if platform.system() == "Windows":
return os.getlogin()
else:
return pwd.getpwuid(os.getuid()).pw_name
def create_default_filename(model_name):
time_str = time.strftime("%Y-%m-%d_%H-%M-%S")
return f"{model_name}/chat_{time_str}.json"
def save_chat(chat, args, filename):
output_dict = {}
output_dict["settings"] = vars(args)
output_dict["chat_history"] = chat
folder = args.save_folder
if filename is None:
filename = create_default_filename(args.model_name_or_path)
filename = os.path.join(folder, filename)
os.makedirs(os.path.dirname(filename), exist_ok=True)
with open(filename, "w") as f:
json.dump(output_dict, f, indent=4)
return os.path.abspath(filename)
def clear_chat_history(system_prompt):
if system_prompt is None:
chat = []
else:
chat = [{"role": "system", "content": system_prompt}]
return chat
def parse_settings(user_input, current_args, interface):
settings = user_input[4:].strip().split(";")
settings = [(setting.split("=")[0], setting[len(setting.split("=")[0]) + 1 :]) for setting in settings]
settings = dict(settings)
error = False
for name in settings:
if hasattr(current_args, name):
try:
if isinstance(getattr(current_args, name), bool):
if settings[name] == "True":
settings[name] = True
elif settings[name] == "False":
settings[name] = False
else:
raise ValueError
else:
settings[name] = type(getattr(current_args, name))(settings[name])
except ValueError:
interface.print_red(
f"Cannot cast setting {name} (={settings[name]}) to {type(getattr(current_args, name))}."
)
else:
interface.print_red(f"There is no '{name}' setting.")
if error:
interface.print_red("There was an issue parsing the settings. No settings have been changed.")
return current_args, False
else:
for name in settings:
setattr(current_args, name, settings[name])
interface.print_green(f"Set {name} to {settings[name]}.")
time.sleep(1.5) # so the user has time to read the changes
return current_args, True
def get_quantization_config(model_args) -> Optional["BitsAndBytesConfig"]:
if model_args.load_in_4bit:
quantization_config = BitsAndBytesConfig(
load_in_4bit=True,
bnb_4bit_compute_dtype=model_args.torch_dtype, # For consistency with model weights, we use the same value as `torch_dtype`
bnb_4bit_quant_type=model_args.bnb_4bit_quant_type,
bnb_4bit_use_double_quant=model_args.use_bnb_nested_quant,
bnb_4bit_quant_storage=model_args.torch_dtype,
)
elif model_args.load_in_8bit:
quantization_config = BitsAndBytesConfig(
load_in_8bit=True,
)
else:
quantization_config = None
return quantization_config
def load_model_and_tokenizer(args):
tokenizer = AutoTokenizer.from_pretrained(
args.model_name_or_path,
revision=args.model_revision,
trust_remote_code=args.trust_remote_code,
)
torch_dtype = args.torch_dtype if args.torch_dtype in ["auto", None] else getattr(torch, args.torch_dtype)
quantization_config = get_quantization_config(args)
model_kwargs = {
"revision": args.model_revision,
"attn_implementation": args.attn_implementation,
"torch_dtype": torch_dtype,
"device_map": "auto",
"quantization_config": quantization_config,
}
model = AutoModelForCausalLM.from_pretrained(
args.model_name_or_path, trust_remote_code=args.trust_remote_code, **model_kwargs
)
if getattr(model, "hf_device_map", None) is None:
model = model.to(args.device)
return model, tokenizer
def parse_eos_tokens(tokenizer, eos_tokens, eos_token_ids):
if tokenizer.pad_token_id is None:
pad_token_id = tokenizer.eos_token_id
else:
pad_token_id = tokenizer.pad_token_id
all_eos_token_ids = []
if eos_tokens is not None:
all_eos_token_ids.extend(tokenizer.convert_tokens_to_ids(eos_tokens.split(",")))
if eos_token_ids is not None:
all_eos_token_ids.extend([int(token_id) for token_id in eos_token_ids.split(",")])
if len(all_eos_token_ids) == 0:
all_eos_token_ids.append(tokenizer.eos_token_id)
return pad_token_id, all_eos_token_ids
class RichInterface:
def __init__(self, model_name=None, user_name=None):
self._console = Console()
if model_name is None:
self.model_name = "assistant"
else:
self.model_name = model_name
if user_name is None:
self.user_name = "user"
else:
self.user_name = user_name
def stream_output(self, output_stream):
"""Stream output from a role."""
# This method is originally from the FastChat CLI: https://github.com/lm-sys/FastChat/blob/main/fastchat/serve/cli.py
# Create a Live context for updating the console output
text = ""
self._console.print(f"[bold blue]<{self.model_name}>:")
with Live(console=self._console, refresh_per_second=4) as live:
# Read lines from the stream
for i, outputs in enumerate(output_stream):
if not outputs or i == 0:
continue
text += outputs
# Render the accumulated text as Markdown
# NOTE: this is a workaround for the rendering "unstandard markdown"
# in rich. The chatbots output treat "\n" as a new line for
# better compatibility with real-world text. However, rendering
# in markdown would break the format. It is because standard markdown
# treat a single "\n" in normal text as a space.
# Our workaround is adding two spaces at the end of each line.
# This is not a perfect solution, as it would
# introduce trailing spaces (only) in code block, but it works well
# especially for console output, because in general the console does not
# care about trailing spaces.
lines = []
for line in text.splitlines():
lines.append(line)
if line.startswith("```"):
# Code block marker - do not add trailing spaces, as it would
# break the syntax highlighting
lines.append("\n")
else:
lines.append(" \n")
markdown = Markdown("".join(lines).strip(), code_theme="github-dark")
# Update the Live console output
live.update(markdown)
self._console.print()
return text
def input(self):
input = self._console.input(f"[bold red]<{self.user_name}>:\n")
self._console.print()
return input
def clear(self):
self._console.clear()
def print_user_message(self, text):
self._console.print(f"[bold red]<{self.user_name}>:[/ bold red]\n{text}")
self._console.print()
def print_green(self, text):
self._console.print(f"[bold green]{text}")
self._console.print()
def print_red(self, text):
self._console.print(f"[bold red]{text}")
self._console.print()
def print_help(self):
self._console.print(Markdown(HELP_STRING))
self._console.print()
@dataclass
class ChatArguments:
r"""
Arguments for the chat script.
Args:
model_name_or_path (`str`):
Name of the pre-trained model.
user (`str` or `None`, *optional*, defaults to `None`):
Username to display in chat interface.
system_prompt (`str` or `None`, *optional*, defaults to `None`):
System prompt.
save_folder (`str`, *optional*, defaults to `"./chat_history/"`):
Folder to save chat history.
device (`str`, *optional*, defaults to `"cpu"`):
Device to use for inference.
examples_path (`str` or `None`, *optional*, defaults to `None`):
Path to a yaml file with examples.
max_new_tokens (`int`, *optional*, defaults to `256`):
Maximum number of tokens to generate.
do_sample (`bool`, *optional*, defaults to `True`):
Whether to sample outputs during generation.
num_beams (`int`, *optional*, defaults to `1`):
Number of beams for beam search.
temperature (`float`, *optional*, defaults to `1.0`):
Temperature parameter for generation.
top_k (`int`, *optional*, defaults to `50`):
Value of k for top-k sampling.
top_p (`float`, *optional*, defaults to `1.0`):
Value of p for nucleus sampling.
repetition_penalty (`float`, *optional*, defaults to `1.0`):
Repetition penalty.
eos_tokens (`str` or `None`, *optional*, defaults to `None`):
EOS tokens to stop the generation. If multiple they should be comma separated.
eos_token_ids (`str` or `None`, *optional*, defaults to `None`):
EOS token IDs to stop the generation. If multiple they should be comma separated.
model_revision (`str`, *optional*, defaults to `"main"`):
Specific model version to use (can be a branch name, tag name or commit id).
torch_dtype (`str` or `None`, *optional*, defaults to `None`):
Override the default `torch.dtype` and load the model under this dtype. If `'auto'` is passed, the dtype
will be automatically derived from the model's weights.
trust_remote_code (`bool`, *optional*, defaults to `False`):
Whether to trust remote code when loading a model.
attn_implementation (`str` or `None`, *optional*, defaults to `None`):
Which attention implementation to use; you can run --attn_implementation=flash_attention_2, in which case
you must install this manually by running `pip install flash-attn --no-build-isolation`.
load_in_8bit (`bool`, *optional*, defaults to `False`):
Whether to use 8 bit precision for the base model - works only with LoRA.
load_in_4bit (`bool`, *optional*, defaults to `False`):
Whether to use 4 bit precision for the base model - works only with LoRA.
bnb_4bit_quant_type (`str`, *optional*, defaults to `"nf4"`):
Quantization type.
use_bnb_nested_quant (`bool`, *optional*, defaults to `False`):
Whether to use nested quantization.
"""
# General settings
model_name_or_path: str = field(metadata={"help": "Name of the pre-trained model."})
user: Optional[str] = field(default=None, metadata={"help": "Username to display in chat interface."})
system_prompt: Optional[str] = field(default=None, metadata={"help": "System prompt."})
save_folder: str = field(default="./chat_history/", metadata={"help": "Folder to save chat history."})
device: str = field(default="cpu", metadata={"help": "Device to use for inference."})
examples_path: Optional[str] = field(default=None, metadata={"help": "Path to a yaml file with examples."})
# Generation settings
max_new_tokens: int = field(default=256, metadata={"help": "Maximum number of tokens to generate."})
do_sample: bool = field(default=True, metadata={"help": "Whether to sample outputs during generation."})
num_beams: int = field(default=1, metadata={"help": "Number of beams for beam search."})
temperature: float = field(default=1.0, metadata={"help": "Temperature parameter for generation."})
top_k: int = field(default=50, metadata={"help": "Value of k for top-k sampling."})
top_p: float = field(default=1.0, metadata={"help": "Value of p for nucleus sampling."})
repetition_penalty: float = field(default=1.0, metadata={"help": "Repetition penalty."})
eos_tokens: Optional[str] = field(
default=None,
metadata={"help": "EOS tokens to stop the generation. If multiple they should be comma separated."},
)
eos_token_ids: Optional[str] = field(
default=None,
metadata={"help": "EOS token IDs to stop the generation. If multiple they should be comma separated."},
)
# Model loading
model_revision: str = field(
default="main",
metadata={"help": "Specific model version to use (can be a branch name, tag name or commit id)."},
)
torch_dtype: Optional[str] = field(
default="auto",
metadata={
"help": "Override the default `torch.dtype` and load the model under this dtype. If `'auto'` is passed, "
"the dtype will be automatically derived from the model's weights.",
"choices": ["auto", "bfloat16", "float16", "float32"],
},
)
trust_remote_code: bool = field(
default=False, metadata={"help": "Whether to trust remote code when loading a model."}
)
attn_implementation: Optional[str] = field(
default=None,
metadata={
"help": "Which attention implementation to use; you can run --attn_implementation=flash_attention_2, in "
"which case you must install this manually by running `pip install flash-attn --no-build-isolation`."
},
)
load_in_8bit: bool = field(
default=False,
metadata={"help": "Whether to use 8 bit precision for the base model - works only with LoRA."},
)
load_in_4bit: bool = field(
default=False,
metadata={"help": "Whether to use 4 bit precision for the base model - works only with LoRA."},
)
bnb_4bit_quant_type: str = field(default="nf4", metadata={"help": "Quantization type.", "choices": ["fp4", "nf4"]})
use_bnb_nested_quant: bool = field(default=False, metadata={"help": "Whether to use nested quantization."})
def chat_command_factory(args: Namespace):
"""
Factory function used to chat with a local model.
"""
return ChatCommand(args)
class ChatCommand(BaseTransformersCLICommand):
@staticmethod
def register_subcommand(parser: ArgumentParser):
"""
Register this command to argparse so it's available for the transformer-cli
Args:
parser: Root parser to register command-specific arguments
"""
dataclass_types = (ChatArguments,)
chat_parser = parser.add_parser("chat", help=HELP_STRING, dataclass_types=dataclass_types)
chat_parser.set_defaults(func=chat_command_factory)
def __init__(self, args):
self.args = args
@staticmethod
def is_valid_setting_command(s: str) -> bool:
# First check the basic structure
if not s.startswith("set ") or "=" not in s:
return False
# Split into individual assignments
assignments = [a.strip() for a in s[4:].split(";") if a.strip()]
for assignment in assignments:
# Each assignment should have exactly one '='
if assignment.count("=") != 1:
return False
key, value = assignment.split("=", 1)
key = key.strip()
value = value.strip()
if not key or not value:
return False
# Keys can only have alphabetic characters, spaces and underscores
if not set(key).issubset(ALLOWED_KEY_CHARS):
return False
# Values can have just about anything that isn't a semicolon
if not set(value).issubset(ALLOWED_VALUE_CHARS):
return False
return True
def run(self):
if not is_rich_available():
raise ImportError("You need to install rich to use the chat interface. (`pip install rich`)")
if not is_torch_available():
raise ImportError("You need to install torch to use the chat interface. (`pip install torch`)")
args = self.args
if args.examples_path is None:
examples = DEFAULT_EXAMPLES
else:
with open(args.examples_path) as f:
examples = yaml.safe_load(f)
current_args = copy.deepcopy(args)
if args.user is None:
user = get_username()
else:
user = args.user
model, tokenizer = load_model_and_tokenizer(args)
generation_streamer = TextIteratorStreamer(tokenizer, skip_special_tokens=True, skip_prompt=True)
pad_token_id, eos_token_ids = parse_eos_tokens(tokenizer, args.eos_tokens, args.eos_token_ids)
interface = RichInterface(model_name=args.model_name_or_path, user_name=user)
interface.clear()
chat = clear_chat_history(current_args.system_prompt)
while True:
try:
user_input = interface.input()
if user_input == "clear":
chat = clear_chat_history(current_args.system_prompt)
interface.clear()
continue
if user_input == "help":
interface.print_help()
continue
if user_input == "exit":
break
if user_input == "reset":
interface.clear()
current_args = copy.deepcopy(args)
chat = clear_chat_history(current_args.system_prompt)
continue
if user_input.startswith("save") and len(user_input.split()) < 2:
split_input = user_input.split()
if len(split_input) == 2:
filename = split_input[1]
else:
filename = None
filename = save_chat(chat, current_args, filename)
interface.print_green(f"Chat saved in {filename}!")
continue
if self.is_valid_setting_command(user_input):
current_args, success = parse_settings(user_input, current_args, interface)
if success:
chat = []
interface.clear()
continue
if user_input.startswith("example") and len(user_input.split()) == 2:
example_name = user_input.split()[1]
if example_name in examples:
interface.clear()
chat = []
interface.print_user_message(examples[example_name]["text"])
user_input = examples[example_name]["text"]
else:
interface.print_red(
f"Example {example_name} not found in list of available examples: {list(examples.keys())}."
)
continue
chat.append({"role": "user", "content": user_input})
inputs = tokenizer.apply_chat_template(chat, return_tensors="pt", add_generation_prompt=True).to(
model.device
)
attention_mask = torch.ones_like(inputs)
generation_kwargs = {
"inputs": inputs,
"attention_mask": attention_mask,
"streamer": generation_streamer,
"max_new_tokens": current_args.max_new_tokens,
"do_sample": current_args.do_sample,
"num_beams": current_args.num_beams,
"temperature": current_args.temperature,
"top_k": current_args.top_k,
"top_p": current_args.top_p,
"repetition_penalty": current_args.repetition_penalty,
"pad_token_id": pad_token_id,
"eos_token_id": eos_token_ids,
}
thread = Thread(target=model.generate, kwargs=generation_kwargs)
thread.start()
model_output = interface.stream_output(generation_streamer)
thread.join()
chat.append({"role": "assistant", "content": model_output})
except KeyboardInterrupt:
break