Struct lib_wc::sync::RateLimiter

pub struct RateLimiter { /* private fields */ }

A client-side rate limiter. This is useful for limiting the number of queries sent to a server from a single client. For example, it is useful inside of a web crawler to limit the number of requests sent by the crawler.

The rate limit is a “best effort” rate limit. It is not guaranteed that the rate limit will be exactly the specified number of queries per second. It is possible that the rate limit will be exceeded by a small amount.

Implementations

impl RateLimiter

pub fn new(max_qps: f64) -> Result<Self>

Creates a new rate limiter.

Returns an error if the max QPS is 0.

Examples

use tokio::sync::Mutex;
use anyhow::Result;
use lib_wc::sync::RateLimiter;

#[tokio::main]
async fn main() -> Result<()> {
    let max_qps = 100.0;
    RateLimiter::new(max_qps)?;
    Ok(())
}

pub async fn acquire(&self) -> Result<()>

Waits for the rate limiter to allow the client to send another query.

Examples

use tokio::sync::Mutex;
use anyhow::Result;
use lib_wc::sync::RateLimiter;

#[tokio::main]
async fn main() -> Result<()> {
    let max_qps = 1.0;
    let rate_limiter = RateLimiter::new(max_qps)?;   

    for _ in 0..1 {
       rate_limiter.acquire().await?;
       // Send a query to a server
    }

   Ok(())
}