prompt.py — langchain Source File

Source Code

"""Prompt schema definition."""

from __future__ import annotations

from pathlib import Path
from typing import TYPE_CHECKING, Any

from pydantic import BaseModel, model_validator
from typing_extensions import override

from langchain_core.prompts.string import (
    DEFAULT_FORMATTER_MAPPING,
    PromptTemplateFormat,
    StringPromptTemplate,
    check_valid_template,
    get_template_variables,
    mustache_schema,
)

if TYPE_CHECKING:
    from langchain_core.runnables.config import RunnableConfig


class PromptTemplate(StringPromptTemplate):
    """Prompt template for a language model.

    A prompt template consists of a string template. It accepts a set of parameters
    from the user that can be used to generate a prompt for a language model.

    The template can be formatted using either f-strings (default), jinja2, or mustache
    syntax.

    !!! warning "Security"

        Prefer using `template_format='f-string'` instead of `template_format='jinja2'`,
        or make sure to NEVER accept jinja2 templates from untrusted sources as they may
        lead to arbitrary Python code execution.

        As of LangChain 0.0.329, Jinja2 templates will be rendered using Jinja2's
        SandboxedEnvironment by default. This sand-boxing should be treated as a
        best-effort approach rather than a guarantee of security, as it is an opt-out
        rather than opt-in approach.

        Despite the sandboxing, we recommend to never use jinja2 templates from
        untrusted sources.

    Example:
        ```python
        from langchain_core.prompts import PromptTemplate

        # Instantiation using from_template (recommended)
        prompt = PromptTemplate.from_template("Say {foo}")
        prompt.format(foo="bar")

        # Instantiation using initializer
        prompt = PromptTemplate(template="Say {foo}")
        ```
    """

    @property
// ... (253 more lines)