loading.py — langchain Source File

Source Code

"""Load prompts."""

import json
import logging
from collections.abc import Callable
from pathlib import Path

import yaml

from langchain_core.output_parsers.string import StrOutputParser
from langchain_core.prompts.base import BasePromptTemplate
from langchain_core.prompts.chat import ChatPromptTemplate
from langchain_core.prompts.few_shot import FewShotPromptTemplate
from langchain_core.prompts.prompt import PromptTemplate

URL_BASE = "https://raw.githubusercontent.com/hwchase17/langchain-hub/master/prompts/"
logger = logging.getLogger(__name__)


def load_prompt_from_config(config: dict) -> BasePromptTemplate:
    """Load prompt from config dict.

    Args:
        config: Dict containing the prompt configuration.

    Returns:
        A `PromptTemplate` object.

    Raises:
        ValueError: If the prompt type is not supported.
    """
    if "_type" not in config:
        logger.warning("No `_type` key found, defaulting to `prompt`.")
    config_type = config.pop("_type", "prompt")

    if config_type not in type_to_loader_dict:
        msg = f"Loading {config_type} prompt not supported"
        raise ValueError(msg)

    prompt_loader = type_to_loader_dict[config_type]
    return prompt_loader(config)


def _load_template(var_name: str, config: dict) -> dict:
    """Load template from the path if applicable."""
    # Check if template_path exists in config.
    if f"{var_name}_path" in config:
        # If it does, make sure template variable doesn't also exist.
        if var_name in config:
            msg = f"Both `{var_name}_path` and `{var_name}` cannot be provided."
            raise ValueError(msg)
        # Pop the template path from the config.
        template_path = Path(config.pop(f"{var_name}_path"))
        # Load the template.
        if template_path.suffix == ".txt":
            template = template_path.read_text(encoding="utf-8")
        else:
            raise ValueError
        # Set the template variable to the extracted variable.
        config[var_name] = template
// ... (138 more lines)