BaseRateLimiter Class — langchain Architecture

Source Code

libs/core/langchain_core/rate_limiters.py lines 11–64

class BaseRateLimiter(abc.ABC):
    """Base class for rate limiters.

    Usage of the base limiter is through the acquire and aacquire methods depending
    on whether running in a sync or async context.

    Implementations are free to add a timeout parameter to their initialize method
    to allow users to specify a timeout for acquiring the necessary tokens when
    using a blocking call.

    Current limitations:

    - Rate limiting information is not surfaced in tracing or callbacks. This means
        that the total time it takes to invoke a chat model will encompass both
        the time spent waiting for tokens and the time spent making the request.
    """

    @abc.abstractmethod
    def acquire(self, *, blocking: bool = True) -> bool:
        """Attempt to acquire the necessary tokens for the rate limiter.

        This method blocks until the required tokens are available if `blocking`
        is set to `True`.

        If `blocking` is set to `False`, the method will immediately return the result
        of the attempt to acquire the tokens.

        Args:
            blocking: If `True`, the method will block until the tokens are available.
                If `False`, the method will return immediately with the result of
                the attempt.

        Returns:
            `True` if the tokens were successfully acquired, `False` otherwise.
        """

    @abc.abstractmethod
    async def aacquire(self, *, blocking: bool = True) -> bool:
        """Attempt to acquire the necessary tokens for the rate limiter.

        This method blocks until the required tokens are available if `blocking`
        is set to `True`.

        If `blocking` is set to `False`, the method will immediately return the result
        of the attempt to acquire the tokens.

        Args:
            blocking: If `True`, the method will block until the tokens are available.
                If `False`, the method will return immediately with the result of
                the attempt.

        Returns:
            `True` if the tokens were successfully acquired, `False` otherwise.
        """