mirror of
https://github.com/hwchase17/langchain
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0bc4a9b3fc
* **Description:** Adds a simple LLM implementation for interacting with [llamafile](https://github.com/Mozilla-Ocho/llamafile)-based models. * **Dependencies:** N/A * **Issue:** N/A **Detail** [llamafile](https://github.com/Mozilla-Ocho/llamafile) lets you run LLMs locally from a single file on most computers without installing any dependencies. To use the llamafile LLM implementation, the user needs to: 1. Download a llamafile e.g. https://huggingface.co/jartine/TinyLlama-1.1B-Chat-v1.0-GGUF/resolve/main/TinyLlama-1.1B-Chat-v1.0.Q5_K_M.llamafile?download=true 2. Make the file executable. 3. Run the llamafile in 'server mode'. (All llamafiles come packaged with a lightweight server; by default, the server listens at `http://localhost:8080`.) ```bash wget https://url/of/model.llamafile chmod +x model.llamafile ./model.llamafile --server --nobrowser ``` Now, the user can invoke the LLM via the LangChain client: ```python from langchain_community.llms.llamafile import Llamafile llm = Llamafile() llm.invoke("Tell me a joke.") ```
319 lines
10 KiB
Python
319 lines
10 KiB
Python
from __future__ import annotations
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import json
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from io import StringIO
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from typing import Any, Dict, Iterator, List, Optional
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import requests
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from langchain_core.callbacks.manager import CallbackManagerForLLMRun
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from langchain_core.language_models.llms import LLM
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from langchain_core.outputs import GenerationChunk
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from langchain_core.pydantic_v1 import Extra
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from langchain_core.utils import get_pydantic_field_names
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class Llamafile(LLM):
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"""Llamafile lets you distribute and run large language models with a
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single file.
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To get started, see: https://github.com/Mozilla-Ocho/llamafile
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To use this class, you will need to first:
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1. Download a llamafile.
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2. Make the downloaded file executable: `chmod +x path/to/model.llamafile`
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3. Start the llamafile in server mode:
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`./path/to/model.llamafile --server --nobrowser`
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Example:
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.. code-block:: python
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from langchain_community.llms import Llamafile
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llm = Llamafile()
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llm.invoke("Tell me a joke.")
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"""
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base_url: str = "http://localhost:8080"
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"""Base url where the llamafile server is listening."""
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request_timeout: Optional[int] = None
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"""Timeout for server requests"""
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streaming: bool = False
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"""Allows receiving each predicted token in real-time instead of
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waiting for the completion to finish. To enable this, set to true."""
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# Generation options
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seed: int = -1
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"""Random Number Generator (RNG) seed. A random seed is used if this is
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less than zero. Default: -1"""
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temperature: float = 0.8
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"""Temperature. Default: 0.8"""
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top_k: int = 40
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"""Limit the next token selection to the K most probable tokens.
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Default: 40."""
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top_p: float = 0.95
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"""Limit the next token selection to a subset of tokens with a cumulative
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probability above a threshold P. Default: 0.95."""
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min_p: float = 0.05
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"""The minimum probability for a token to be considered, relative to
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the probability of the most likely token. Default: 0.05."""
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n_predict: int = -1
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"""Set the maximum number of tokens to predict when generating text.
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Note: May exceed the set limit slightly if the last token is a partial
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multibyte character. When 0, no tokens will be generated but the prompt
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is evaluated into the cache. Default: -1 = infinity."""
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n_keep: int = 0
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"""Specify the number of tokens from the prompt to retain when the
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context size is exceeded and tokens need to be discarded. By default,
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this value is set to 0 (meaning no tokens are kept). Use -1 to retain all
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tokens from the prompt."""
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tfs_z: float = 1.0
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"""Enable tail free sampling with parameter z. Default: 1.0 = disabled."""
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typical_p: float = 1.0
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"""Enable locally typical sampling with parameter p.
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Default: 1.0 = disabled."""
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repeat_penalty: float = 1.1
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"""Control the repetition of token sequences in the generated text.
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Default: 1.1"""
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repeat_last_n: int = 64
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"""Last n tokens to consider for penalizing repetition. Default: 64,
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0 = disabled, -1 = ctx-size."""
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penalize_nl: bool = True
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"""Penalize newline tokens when applying the repeat penalty.
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Default: true."""
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presence_penalty: float = 0.0
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"""Repeat alpha presence penalty. Default: 0.0 = disabled."""
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frequency_penalty: float = 0.0
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"""Repeat alpha frequency penalty. Default: 0.0 = disabled"""
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mirostat: int = 0
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"""Enable Mirostat sampling, controlling perplexity during text
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generation. 0 = disabled, 1 = Mirostat, 2 = Mirostat 2.0.
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Default: disabled."""
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mirostat_tau: float = 5.0
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"""Set the Mirostat target entropy, parameter tau. Default: 5.0."""
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mirostat_eta: float = 0.1
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"""Set the Mirostat learning rate, parameter eta. Default: 0.1."""
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class Config:
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"""Configuration for this pydantic object."""
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extra = Extra.forbid
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@property
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def _llm_type(self) -> str:
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return "llamafile"
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@property
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def _param_fieldnames(self) -> List[str]:
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# Return the list of fieldnames that will be passed as configurable
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# generation options to the llamafile server. Exclude 'builtin' fields
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# from the BaseLLM class like 'metadata' as well as fields that should
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# not be passed in requests (base_url, request_timeout).
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ignore_keys = [
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"base_url",
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"cache",
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"callback_manager",
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"callbacks",
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"metadata",
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"name",
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"request_timeout",
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"streaming",
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"tags",
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"verbose",
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]
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attrs = [
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k for k in get_pydantic_field_names(self.__class__) if k not in ignore_keys
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]
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return attrs
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@property
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def _default_params(self) -> Dict[str, Any]:
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params = {}
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for fieldname in self._param_fieldnames:
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params[fieldname] = getattr(self, fieldname)
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return params
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def _get_parameters(
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self, stop: Optional[List[str]] = None, **kwargs: Any
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) -> Dict[str, Any]:
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params = self._default_params
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# Only update keys that are already present in the default config.
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# This way, we don't accidentally post unknown/unhandled key/values
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# in the request to the llamafile server
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for k, v in kwargs.items():
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if k in params:
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params[k] = v
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if stop is not None and len(stop) > 0:
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params["stop"] = stop
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if self.streaming:
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params["stream"] = True
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return params
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def _call(
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self,
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prompt: str,
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stop: Optional[List[str]] = None,
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run_manager: Optional[CallbackManagerForLLMRun] = None,
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**kwargs: Any,
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) -> str:
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"""Request prompt completion from the llamafile server and return the
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output.
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Args:
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prompt: The prompt to use for generation.
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stop: A list of strings to stop generation when encountered.
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run_manager:
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**kwargs: Any additional options to pass as part of the
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generation request.
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Returns:
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The string generated by the model.
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"""
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if self.streaming:
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with StringIO() as buff:
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for chunk in self._stream(
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prompt, stop=stop, run_manager=run_manager, **kwargs
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):
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buff.write(chunk.text)
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text = buff.getvalue()
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return text
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else:
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params = self._get_parameters(stop=stop, **kwargs)
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payload = {"prompt": prompt, **params}
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try:
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response = requests.post(
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url=f"{self.base_url}/completion",
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headers={
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"Content-Type": "application/json",
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},
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json=payload,
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stream=False,
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timeout=self.request_timeout,
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)
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except requests.exceptions.ConnectionError:
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raise requests.exceptions.ConnectionError(
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f"Could not connect to Llamafile server. Please make sure "
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f"that a server is running at {self.base_url}."
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)
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response.raise_for_status()
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response.encoding = "utf-8"
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text = response.json()["content"]
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return text
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def _stream(
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self,
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prompt: str,
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stop: Optional[List[str]] = None,
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run_manager: Optional[CallbackManagerForLLMRun] = None,
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**kwargs: Any,
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) -> Iterator[GenerationChunk]:
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"""Yields results objects as they are generated in real time.
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It also calls the callback manager's on_llm_new_token event with
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similar parameters to the OpenAI LLM class method of the same name.
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Args:
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prompt: The prompts to pass into the model.
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stop: Optional list of stop words to use when generating.
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run_manager:
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**kwargs: Any additional options to pass as part of the
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generation request.
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Returns:
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A generator representing the stream of tokens being generated.
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Yields:
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Dictionary-like objects each containing a token
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Example:
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.. code-block:: python
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from langchain_community.llms import Llamafile
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llm = Llamafile(
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temperature = 0.0
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)
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for chunk in llm.stream("Ask 'Hi, how are you?' like a pirate:'",
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stop=["'","\n"]):
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result = chunk["choices"][0]
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print(result["text"], end='', flush=True)
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"""
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params = self._get_parameters(stop=stop, **kwargs)
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if "stream" not in params:
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params["stream"] = True
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payload = {"prompt": prompt, **params}
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try:
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response = requests.post(
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url=f"{self.base_url}/completion",
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headers={
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"Content-Type": "application/json",
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},
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json=payload,
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stream=True,
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timeout=self.request_timeout,
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)
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except requests.exceptions.ConnectionError:
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raise requests.exceptions.ConnectionError(
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f"Could not connect to Llamafile server. Please make sure "
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f"that a server is running at {self.base_url}."
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)
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response.encoding = "utf8"
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for raw_chunk in response.iter_lines(decode_unicode=True):
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content = self._get_chunk_content(raw_chunk)
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chunk = GenerationChunk(text=content)
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yield chunk
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if run_manager:
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run_manager.on_llm_new_token(token=chunk.text)
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def _get_chunk_content(self, chunk: str) -> str:
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"""When streaming is turned on, llamafile server returns lines like:
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'data: {"content":" They","multimodal":true,"slot_id":0,"stop":false}'
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Here, we convert this to a dict and return the value of the 'content'
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field
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"""
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if chunk.startswith("data:"):
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cleaned = chunk.lstrip("data: ")
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data = json.loads(cleaned)
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return data["content"]
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else:
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return chunk
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