garage/src/util/token_bucket.rs

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Rust
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2021-10-27 08:36:04 +00:00
use std::time::{Duration, Instant};
use tokio::time::sleep;
pub struct TokenBucket {
// Replenish rate: number of tokens per second
replenish_rate: u64,
// Current number of tokens
tokens: u64,
// Last replenish time
last_replenish: Instant,
}
impl TokenBucket {
pub fn new(replenish_rate: u64) -> Self {
Self {
replenish_rate,
tokens: 0,
last_replenish: Instant::now(),
}
}
pub async fn take(&mut self, tokens: u64) {
while self.tokens < tokens {
let needed = tokens - self.tokens;
let delay = (needed as f64) / (self.replenish_rate as f64);
sleep(Duration::from_secs_f64(delay)).await;
self.replenish();
}
self.tokens -= tokens;
}
pub fn replenish(&mut self) {
let now = Instant::now();
let new_tokens =
((now - self.last_replenish).as_secs_f64() * (self.replenish_rate as f64)) as u64;
self.tokens += new_tokens;
self.last_replenish = now;
}
}