Salvo Concurrency Limiter

max_concurrency(n) from salvo::concurrency_limiter is a hoop that wraps a tokio::sync::Semaphore. It try_acquires on each request — on failure it short-circuits with 429 Too Many Requests. Unlike rate limiters it caps parallel requests, not request frequency.

Setup

Lives in salvo-extra; enable the feature:

[dependencies]
salvo = { version = "0.89.3", features = ["concurrency-limiter"] }

Import path: salvo::concurrency_limiter::{max_concurrency, MaxConcurrency}.

Basic usage