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//! A libray for weighted balancing algorithm. //! It provides three weighted balancing (elect) algorithm. //! One is random algorithm. //! Another is weighted balancing algorithm used by LVS. //! The third is smooth weighted balancing algorithm used by Nginx. //! //! The LVS weighted round-robin scheduling is introduced at http://kb.linuxvirtualserver.org/wiki/Weighted_Round-Robin_Scheduling. //! The Nginx smooth weighted round-robin balancing algorithm is introduced at https://github.com/phusion/nginx/commit/27e94984486058d73157038f7950a0a36ecc6e35. //! The random algorithm is not smooth although it follows weight configuration. //! Using it is simple: //! ```rust //! use weighted_rs::{SmoothWeight, Weight}; //! use std::collections::HashMap; //! //! let mut sw: SmoothWeight<&str> = SmoothWeight::new(); //! sw.add("server1", 5); //! sw.add("server2", 2); //! sw.add("server3", 3); //! //! for _ in 0..100 { //! let s = sw.next().unwrap(); //! println!("{}", s); //! } //! ``` use std::collections::HashMap; pub mod random_weight; pub mod roundrobin_weight; pub mod smooth_weight; pub use random_weight::*; pub use roundrobin_weight::*; pub use smooth_weight::*; // A common trait for weight algorithm. pub trait Weight { type Item; // next gets next selected item. fn next(&mut self) -> Option<Self::Item>; // add adds a weighted item for selection. fn add(&mut self, item: Self::Item, weight: isize); // all returns all items. fn all(&self) -> HashMap<Self::Item, isize>; // remove_all removes all weighted items. fn remove_all(&mut self); // reset resets the balancing algorithm. fn reset(&mut self); }