D_i$|SrSSKJr SSKrSSKrSSKrSSKr"SS\R5r"SS\5r SS/r g)z;Interface for a rate limiter and an in-memory rate limiter.) annotationsNcx\rSrSrSr\R SS.S Sjj5r\R SS.S Sjj5rSr g) BaseRateLimiter aQBase 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. TblockingcgaAttempt 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. Nselfrs V/home/james-whalen/.local/lib/python3.13/site-packages/langchain_core/rate_limiters.pyacquireBaseRateLimiter.acquiresc # g7fr r r s raacquireBaseRateLimiter.aacquire/ssr Nrboolreturnr) __name__ __module__ __qualname____firstlineno____doc__abcabstractmethodrr__static_attributes__r rrrr sA  *.  $ 15  rrcj\rSrSrSrSSSS.SSjjrSSjrSS .SS jjrSS .SS jjrS r g )InMemoryRateLimiterCaAn in memory rate limiter based on a token bucket algorithm. This is an in memory rate limiter, so it cannot rate limit across different processes. The rate limiter only allows time-based rate limiting and does not take into account any information about the input or the output, so it cannot be used to rate limit based on the size of the request. It is thread safe and can be used in either a sync or async context. The in memory rate limiter is based on a token bucket. The bucket is filled with tokens at a given rate. Each request consumes a token. If there are not enough tokens in the bucket, the request is blocked until there are enough tokens. These tokens have nothing to do with LLM tokens. They are just a way to keep track of how many requests can be made at a given time. Current limitations: - The rate limiter is not designed to work across different processes. It is an in-memory rate limiter, but it is thread safe. - The rate limiter only supports time-based rate limiting. It does not take into account the size of the request or any other factors. Example: ```python import time from langchain_core.rate_limiters import InMemoryRateLimiter rate_limiter = InMemoryRateLimiter( requests_per_second=0.1, # <-- Can only make a request once every 10 seconds!! check_every_n_seconds=0.1, # Wake up every 100 ms to check whether allowed to make a request, max_bucket_size=10, # Controls the maximum burst size. ) from langchain_anthropic import ChatAnthropic model = ChatAnthropic( model_name="claude-sonnet-4-5-20250929", rate_limiter=rate_limiter ) for _ in range(5): tic = time.time() model.invoke("hello") toc = time.time() print(toc - tic) ``` g?)requests_per_secondcheck_every_n_secondsmax_bucket_sizecxXlSUlX0l[R"5UlSUlX lg)aA rate limiter based on a token bucket. These tokens have nothing to do with LLM tokens. They are just a way to keep track of how many requests can be made at a given time. This rate limiter is designed to work in a threaded environment. It works by filling up a bucket with tokens at a given rate. Each request consumes a given number of tokens. If there are not enough tokens in the bucket, the request is blocked until there are enough tokens. Args: requests_per_second: The number of tokens to add per second to the bucket. The tokens represent "credit" that can be used to make requests. check_every_n_seconds: Check whether the tokens are available every this many seconds. Can be a float to represent fractions of a second. max_bucket_size: The maximum number of tokens that can be in the bucket. Must be at least `1`. Used to prevent bursts of requests. gN)r$available_tokensr& threadingLock _consume_locklastr%)r r$r%r&s r__init__InMemoryRateLimiter.__init__xs6:$7 #.'^^-"& %:"rcUR [R"5nURcXlXR- nX R-S:a'U=R X R-- slXl[ UR UR5UlUR S:aU=R S-slSSS5 gSSS5 g!,(df  g=f)zTry to consume a token. Returns: True means that the tokens were consumed, and the caller can proceed to make the request. A False means that the tokens were not consumed, and the caller should try again later. Nr#TF)r+time monotonicr,r$r(minr&)r nowelapseds r_consumeInMemoryRateLimiter._consumes  .."Cyy  IIoG111Q6%%3K3K)KK% %((=(=t?S?S$TD !$$)%%*%) ,-  sB;CC C)TrcU(dUR5$UR5(d7[R"UR5 UR5(dM7g)a Attempt to acquire a token from the rate limiter. This method blocks until the required tokens are available if `blocking` is set to `True`. If `blocking` is set to `False`, the method will immediately return the result of the attempt to acquire the tokens. Args: blocking: If `True`, the method will block until the tokens are available. If `False`, the method will return immediately with the result of the attempt. Returns: `True` if the tokens were successfully acquired, `False` otherwise. T)r5r0sleepr%r s rrInMemoryRateLimiter.acquires@"==? "--// JJt11 2--//rc# U(dUR5$UR5(d?[R"UR5IShvN UR5(dM?gN7f)aAttempt to acquire a token from the rate limiter. Async version. 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. NT)r5asyncior8r%r s rrInMemoryRateLimiter.aacquiresR"==? "--//-- : :; ; ;--// rBsFA"  5 cgg5 pq/qj r