Consistent Hash

Consistent Hashing is a distributed system algorithm for assigning values to partitions in a highly dynamic environment.

Example:

Using the algorithm to LB redis cache. (Crate redis = "0.17.0").

While the key must implement the hash trait to define a hashing strategy.

The Value must implement the Evict trait to define rebalancing behavior.

```rust let mut ring: ConsistentHash = match ConsistentHash::new(100).unwrap();

ring.addnode("redis://my-redis-node-1".tostring(), redis::Client::open("redis://my-redis-node-1")?).unwrap(); ring.addnode("redis://my-redis-node-2".tostring(), redis::Client::open("redis://my-redis-node-2")?).unwrap(); ring.addnode("redis://my-redis-node-3".tostring(), redis::Client::open("redis://my-redis-node-3")?).unwrap(); ring.addnode("redis://my-redis-node-4".tostring(), redis::Client::open("redis://my-redis-node-4")?).unwrap();

let client = match ring.get_node(String::from("some-key")){ Some(node) => node, None => panic!("Not found!"), };

let mut con = client.get_connection()?; con.get("some-key"); ```