Module Limiter.Throttled_rate_limiter

A Throttled_rate_limiter combines a Token_bucket and a Throttle. Unlike a Token_bucket, jobs cannot consume variable numbers of tokens, but the number of outstanding jobs is also limited to max_concurrent_jobs. Like a Throttle, finish_job must be called once, and only once, when a job is completed.

type t = private limiter
val sexp_of_t : t -> Sexplib0.Sexp.t
val create_exn : now:Core.Time_ns.t -> burst_size:int -> sustained_rate_per_sec:float -> max_concurrent_jobs:int -> t
val try_start_job : t -> now:Core.Time_ns.t -> [ `Start | `Max_concurrent_jobs_running | `Unable_until_at_least of Core.Time_ns.t ]
val finish_job : t -> now:Core.Time_ns.t -> unit

Return a token to the hopper (not the bucket). Thus, max_concurrent_jobs limits not only the number of open try_start_job-finish_job pairs across time, but also applies to the number of jobs run during the same (1ns) quantum time now - whether they finished now or not, and regardless of what order finish_job is called for the same time now.