Crate consistent_hash

An implementation of Consistent hashing algorithm.

Currently this crate only provides StaticHashRing which represents statically built, virtual node based hash rings.

Examples

use consistent_hash::{Node, StaticHashRing, DefaultHash};

let nodes = vec![
    Node::new("foo").quantity(5),
    Node::new("bar").quantity(5),
    Node::new("baz").quantity(1),
    Node::new("baz").quantity(2), // ignored (duplicate key)
];

let ring = StaticHashRing::new(DefaultHash, nodes.into_iter());
assert_eq!(ring.len(), 11);        // virtual node count
assert_eq!(ring.nodes().len(), 3); // real node count

assert_eq!(ring.calc_candidates(&"aa").map(|n| &n.key).collect::<Vec<_>>(),
           [&"bar", &"foo", &"baz"]);
assert_eq!(ring.calc_candidates(&"bb").map(|n| &n.key).collect::<Vec<_>>(),
           [&"foo", &"bar", &"baz"]);

Structs

Candidates

An iterator which represents a sequence of the candidate nodes for an item.

DefaultHash

The default RingHash implementation.

Node

A node in a hash ring.

StaticHashRing

A hash ring which is built statically.

Traits

RingHash

This trait allows calculating hash codes for virtual nodes and items.