108 lines
3.6 KiB
Python
108 lines
3.6 KiB
Python
"""Small replication of AutoTokenizer's chat template system for efficiency"""
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import json
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import pathlib
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from functools import lru_cache
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from importlib.metadata import version as package_version
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from jinja2 import TemplateError
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from jinja2.sandbox import ImmutableSandboxedEnvironment
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from packaging import version
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from pydantic import BaseModel
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from typing import Optional, Dict
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class PromptTemplate(BaseModel):
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"""A template for chat completion prompts."""
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name: str
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template: str
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def get_prompt_from_template(
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messages,
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prompt_template: PromptTemplate,
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add_generation_prompt: bool,
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special_tokens: Optional[Dict[str, str]] = None,
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):
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"""Get a prompt from a template and a list of messages."""
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if version.parse(package_version("jinja2")) < version.parse("3.0.0"):
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raise ImportError(
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"Parsing these chat completion messages requires jinja2 3.0.0 "
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f"or greater. Current version: {package_version('jinja2')}\n"
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"Please upgrade jinja by running the following command: "
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"pip install --upgrade jinja2"
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)
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compiled_template = _compile_template(prompt_template.template)
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return compiled_template.render(
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messages=messages,
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add_generation_prompt=add_generation_prompt,
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**special_tokens,
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)
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# Inspired from
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# https://github.com/huggingface/transformers/blob/main/src/transformers/tokenization_utils_base.py#L1761
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@lru_cache
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def _compile_template(template: str):
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"""Compiles a Jinja2 template"""
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# Exception handler
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def raise_exception(message):
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raise TemplateError(message)
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jinja_env = ImmutableSandboxedEnvironment(trim_blocks=True, lstrip_blocks=True)
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jinja_env.globals["raise_exception"] = raise_exception
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jinja_template = jinja_env.from_string(template)
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return jinja_template
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def get_all_templates():
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"""Fetches all templates from the templates directory"""
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template_directory = pathlib.Path("templates")
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return template_directory.glob("*.jinja")
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def find_template_from_model(model_path: pathlib.Path):
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"""Find a matching template name from a model path."""
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model_name = model_path.name
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template_files = get_all_templates()
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for filepath in template_files:
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template_name = filepath.stem.lower()
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# Check if the template name is present in the model name
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if template_name in model_name.lower():
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return template_name
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else:
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raise LookupError("Could not find template from model name.")
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def get_template_from_file(prompt_template_name: str):
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"""Get a template from a jinja file."""
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template_path = pathlib.Path(f"templates/{prompt_template_name}.jinja")
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if template_path.exists():
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with open(template_path, "r", encoding="utf8") as raw_template:
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return PromptTemplate(
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name=prompt_template_name, template=raw_template.read()
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)
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else:
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# Let the user know if the template file isn't found
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raise FileNotFoundError(f'Template "{prompt_template_name}" not found.')
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# Get a template from a JSON file
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# Requires a key and template name
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def get_template_from_model_json(json_path: pathlib.Path, key: str, name: str):
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"""Get a template from a JSON file. Requires a key and template name"""
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if json_path.exists():
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with open(json_path, "r", encoding="utf8") as config_file:
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model_config = json.load(config_file)
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chat_template = model_config.get(key)
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if chat_template:
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return PromptTemplate(name=name, template=chat_template)
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else:
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raise FileNotFoundError(f'Model JSON path "{json_path}" not found.')
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