1use enum_dispatch::enum_dispatch;
16use rand::seq::IndexedRandom;
17
18#[enum_dispatch]
19pub trait LoadBalance {
20 fn get_peer<'a>(&self, peers: &'a [String]) -> Option<&'a String>;
21}
22
23#[enum_dispatch(LoadBalance)]
24#[derive(Debug)]
25pub enum Loadbalancer {
26 Random,
27}
28
29impl Default for Loadbalancer {
30 fn default() -> Self {
31 Loadbalancer::from(Random)
32 }
33}
34
35#[derive(Debug)]
36pub struct Random;
37
38impl LoadBalance for Random {
39 fn get_peer<'a>(&self, peers: &'a [String]) -> Option<&'a String> {
40 peers.choose(&mut rand::rng())
41 }
42}
43
44#[cfg(test)]
45mod tests {
46 use std::collections::HashSet;
47
48 use super::{LoadBalance, Random};
49
50 #[test]
51 fn test_random_lb() {
52 let peers = vec![
53 "127.0.0.1:3001".to_string(),
54 "127.0.0.1:3002".to_string(),
55 "127.0.0.1:3003".to_string(),
56 "127.0.0.1:3004".to_string(),
57 ];
58 let all: HashSet<String> = peers.clone().into_iter().collect();
59
60 let random = Random;
61 for _ in 0..100 {
62 let peer = random.get_peer(&peers).unwrap();
63 assert!(all.contains(peer));
64 }
65 }
66}