Langchain-Chatchat/models/fastchat_api_llm.py

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"""Wrapper around FastChat APIs."""
from __future__ import annotations
import logging
import sys
import warnings
from abc import ABC
from typing import (
AbstractSet,
Any,
Callable,
Collection,
Dict,
Generator,
List,
Literal,
Mapping,
Optional,
Set,
Tuple,
Union,
)
from pydantic import Extra, Field, root_validator
from tenacity import (
before_sleep_log,
retry,
retry_if_exception_type,
stop_after_attempt,
wait_exponential,
)
from langchain.llms.base import BaseLLM
from langchain.schema import Generation, LLMResult
from langchain.utils import get_from_dict_or_env
from models.base import (RemoteRpcModel,
AnswerResult)
from models.loader import LoaderCheckPoint
import requests
import json
logger = logging.getLogger(__name__)
def _streaming_response_template() -> Dict[str, Any]:
"""
:return: 响应结构
"""
return {
"text": "",
"error_code": 0,
}
def _update_response(response: Dict[str, Any], stream_response: Dict[str, Any]) -> None:
"""Update response from the stream response."""
response["text"] += stream_response["text"]
response["error_code"] += stream_response["error_code"]
class BaseFastChat(BaseLLM):
"""Wrapper around FastChat large language models."""
api_base_url: str = "http://localhost:21002/worker_generate_stream"
model_name: str = "text-davinci-003"
"""Model name to use."""
temperature: float = 0.7
"""What sampling temperature to use."""
max_new_tokens: int = 200
stop: int = 20
batch_size: int = 20
"""Maximum number of retries to make when generating."""
streaming: bool = False
"""Penalizes repeated tokens."""
n: int = 1
"""Whether to stream the results or not."""
allowed_special: Union[Literal["all"], AbstractSet[str]] = set()
"""Set of special tokens that are allowed。"""
disallowed_special: Union[Literal["all"], Collection[str]] = "all"
"""Set of special tokens that are not allowed。"""
class Config:
"""Configuration for this pydantic object."""
extra = Extra.ignore
@root_validator(pre=True)
def build_extra(cls, values: Dict[str, Any]) -> Dict[str, Any]:
"""Build extra kwargs from additional params that were passed in."""
all_required_field_names = {field.alias for field in cls.__fields__.values()}
extra = values.get("model_kwargs", {})
for field_name in list(values):
if field_name not in all_required_field_names:
if field_name in extra:
raise ValueError(f"Found {field_name} supplied twice.")
logger.warning(
f"""WARNING! {field_name} is not default parameter.
{field_name} was transfered to model_kwargs.
Please confirm that {field_name} is what you intended."""
)
extra[field_name] = values.pop(field_name)
values["model_kwargs"] = extra
return values
@property
def _default_params(self) -> Dict[str, Any]:
"""Get the default parameters for calling FastChat API."""
normal_params = {
"model": self.model_name,
"prompt": '',
"max_new_tokens": self.max_new_tokens,
"temperature": self.temperature,
}
return {**normal_params}
def _generate(
self, prompts: List[str], stop: Optional[List[str]] = None
) -> LLMResult:
"""Call out to FastChat's endpoint with k unique prompts.
Args:
prompts: The prompts to pass into the model.
stop: Optional list of stop words to use when generating.
Returns:
The full LLM output.
Example:
.. code-block:: python
response = fastchat.generate(["Tell me a joke."])
"""
# TODO: write a unit test for this
params = self._invocation_params
sub_prompts = self.get_sub_prompts(params, prompts)
choices = []
token_usage: Dict[str, int] = {}
headers = {"User-Agent": "fastchat Client"}
for _prompts in sub_prompts:
params["prompt"] = _prompts[0]
if stop is not None:
if "stop" in params:
raise ValueError("`stop` found in both the input and default params.")
params["stop"] = stop
if self.streaming:
if len(_prompts) > 1:
raise ValueError("Cannot stream results with multiple prompts.")
response_template = _streaming_response_template()
response = requests.post(
self.api_base_url,
headers=headers,
json=params,
stream=True,
)
for stream_resp in response.iter_lines(
chunk_size=8192, decode_unicode=False, delimiter=b"\0"
):
if stream_resp:
data = json.loads(stream_resp.decode("utf-8"))
skip_echo_len = len(_prompts[0])
output = data["text"][skip_echo_len:].strip()
data["text"] = output
self.callback_manager.on_llm_new_token(
output,
verbose=self.verbose,
logprobs=data["error_code"],
)
_update_response(response_template, data)
choices.append(response_template)
else:
response_template = _streaming_response_template()
response = requests.post(
self.api_base_url,
headers=headers,
json=params,
stream=True,
)
for stream_resp in response.iter_lines(
chunk_size=8192, decode_unicode=False, delimiter=b"\0"
):
if stream_resp:
data = json.loads(stream_resp.decode("utf-8"))
skip_echo_len = len(_prompts[0])
output = data["text"][skip_echo_len:].strip()
data["text"] = output
_update_response(response_template, data)
choices.append(response_template)
return self.create_llm_result(choices, prompts, token_usage)
async def _agenerate(
self, prompts: List[str], stop: Optional[List[str]] = None
) -> LLMResult:
"""Call out to FastChat's endpoint async with k unique prompts."""
params = self._invocation_params
sub_prompts = self.get_sub_prompts(params, prompts)
choices = []
token_usage: Dict[str, int] = {}
headers = {"User-Agent": "fastchat Client"}
for _prompts in sub_prompts:
params["prompt"] = _prompts[0]
if stop is not None:
if "stop" in params:
raise ValueError("`stop` found in both the input and default params.")
params["stop"] = stop
if self.streaming:
if len(_prompts) > 1:
raise ValueError("Cannot stream results with multiple prompts.")
response_template = _streaming_response_template()
response = requests.post(
self.api_base_url,
headers=headers,
json=params,
stream=True,
)
for stream_resp in response.iter_lines(
chunk_size=8192, decode_unicode=False, delimiter=b"\0"
):
if stream_resp:
data = json.loads(stream_resp.decode("utf-8"))
skip_echo_len = len(_prompts[0])
output = data["text"][skip_echo_len:].strip()
data["text"] = output
self.callback_manager.on_llm_new_token(
output,
verbose=self.verbose,
logprobs=data["error_code"],
)
_update_response(response_template, data)
choices.append(response_template)
else:
response_template = _streaming_response_template()
response = requests.post(
self.api_base_url,
headers=headers,
json=params,
stream=True,
)
for stream_resp in response.iter_lines(
chunk_size=8192, decode_unicode=False, delimiter=b"\0"
):
if stream_resp:
data = json.loads(stream_resp.decode("utf-8"))
skip_echo_len = len(_prompts[0])
output = data["text"][skip_echo_len:].strip()
data["text"] = output
_update_response(response_template, data)
choices.append(response_template)
return self.create_llm_result(choices, prompts, token_usage)
def get_sub_prompts(
self,
params: Dict[str, Any],
prompts: List[str],
) -> List[List[str]]:
"""Get the sub prompts for llm call."""
if params["max_new_tokens"] == -1:
if len(prompts) != 1:
raise ValueError(
"max_new_tokens set to -1 not supported for multiple inputs."
)
params["max_new_tokens"] = self.max_new_tokens_for_prompt(prompts[0])
# append pload
sub_prompts = [
prompts[i: i + self.batch_size]
for i in range(0, len(prompts), self.batch_size)
]
return sub_prompts
def create_llm_result(
self, choices: Any, prompts: List[str], token_usage: Dict[str, int]
) -> LLMResult:
"""Create the LLMResult from the choices and prompts."""
generations = []
for i, _ in enumerate(prompts):
sub_choices = choices[i * self.n: (i + 1) * self.n]
generations.append(
[
Generation(
text=choice["text"],
generation_info=dict(
finish_reason='over',
logprobs=choice["text"],
),
)
for choice in sub_choices
]
)
llm_output = {"token_usage": token_usage, "model_name": self.model_name}
return LLMResult(generations=generations, llm_output=llm_output)
def stream(self, prompt: str, stop: Optional[List[str]] = None) -> Generator:
"""Call FastChat with streaming flag and return the resulting generator.
BETA: this is a beta feature while we figure out the right abstraction.
Once that happens, this interface could change.
Args:
prompt: The prompts to pass into the model.
stop: Optional list of stop words to use when generating.
Returns:
A generator representing the stream of tokens from OpenAI.
Example:
.. code-block:: python
generator = fastChat.stream("Tell me a joke.")
for token in generator:
yield token
"""
params = self._invocation_params
params["prompt"] = prompt
if stop is not None:
if "stop" in params:
raise ValueError("`stop` found in both the input and default params.")
params["stop"] = stop
headers = {"User-Agent": "fastchat Client"}
response = requests.post(
self.api_base_url,
headers=headers,
json=params,
stream=True,
)
for stream_resp in response.iter_lines(
chunk_size=8192, decode_unicode=False, delimiter=b"\0"
):
if stream_resp:
data = json.loads(stream_resp.decode("utf-8"))
skip_echo_len = len(prompt)
output = data["text"][skip_echo_len:].strip()
data["text"] = output
yield data
@property
def _invocation_params(self) -> Dict[str, Any]:
"""Get the parameters used to invoke the model."""
return self._default_params
@property
def _identifying_params(self) -> Mapping[str, Any]:
"""Get the identifying parameters."""
return {**{"model_name": self.model_name}, **self._default_params}
@property
def _llm_type(self) -> str:
"""Return type of llm."""
return "fastChat"
def get_num_tokens(self, text: str) -> int:
"""Calculate num tokens with tiktoken package."""
# tiktoken NOT supported for Python < 3.8
if sys.version_info[1] < 8:
return super().get_num_tokens(text)
try:
import tiktoken
except ImportError:
raise ValueError(
"Could not import tiktoken python package. "
"This is needed in order to calculate get_num_tokens. "
"Please install it with `pip install tiktoken`."
)
enc = tiktoken.encoding_for_model(self.model_name)
tokenized_text = enc.encode(
text,
allowed_special=self.allowed_special,
disallowed_special=self.disallowed_special,
)
# calculate the number of tokens in the encoded text
return len(tokenized_text)
def modelname_to_contextsize(self, modelname: str) -> int:
"""Calculate the maximum number of tokens possible to generate for a model.
Args:
modelname: The modelname we want to know the context size for.
Returns:
The maximum context size
Example:
.. code-block:: python
max_new_tokens = openai.modelname_to_contextsize("text-davinci-003")
"""
model_token_mapping = {
"vicuna-13b": 2049,
"koala": 2049,
"dolly-v2": 2049,
"oasst": 2049,
"stablelm": 2049,
}
context_size = model_token_mapping.get(modelname, None)
if context_size is None:
raise ValueError(
f"Unknown model: {modelname}. Please provide a valid OpenAI model name."
"Known models are: " + ", ".join(model_token_mapping.keys())
)
return context_size
def max_new_tokens_for_prompt(self, prompt: str) -> int:
"""Calculate the maximum number of tokens possible to generate for a prompt.
Args:
prompt: The prompt to pass into the model.
Returns:
The maximum number of tokens to generate for a prompt.
Example:
.. code-block:: python
max_new_tokens = openai.max_token_for_prompt("Tell me a joke.")
"""
num_tokens = self.get_num_tokens(prompt)
# get max context size for model by name
max_size = self.modelname_to_contextsize(self.model_name)
return max_size - num_tokens
class FastChatAPILLM(RemoteRpcModel, BaseFastChat, ABC):
"""Wrapper around FastChat large language models.
Example:
.. code-block:: python
openai = FastChat(model_name="vicuna")
"""
checkPoint: LoaderCheckPoint = None
history_len: int = 10
def __init__(self, checkPoint: LoaderCheckPoint = None):
super().__init__()
self.checkPoint = checkPoint
@property
def _invocation_params(self) -> Dict[str, Any]:
return {**{"model": self.model_name}, **super()._invocation_params}
@property
def _check_point(self) -> LoaderCheckPoint:
return self.checkPoint
@property
def _history_len(self) -> int:
return self.history_len
def set_history_len(self, history_len: int = 10) -> None:
self.history_len = history_len
@property
def _api_key(self) -> str:
pass
@property
def _api_base_url(self) -> str:
return self.api_base_url
def set_api_key(self, api_key: str):
pass
def set_api_base_url(self, api_base_url: str):
self.api_base_url = api_base_url
def call_model_name(self, model_name):
self.model_name = model_name
def generatorAnswer(self, prompt: str,
history: List[List[str]] = [],
streaming: bool = False):
generator = self.stream("Tell me a joke.")
for token in generator:
yield token
history += [[prompt, token["text"]]]
answer_result = AnswerResult()
answer_result.history = history
answer_result.llm_output = {"answer": token["text"]}
yield answer_result