Struct ConsistentHashRing 

pub struct ConsistentHashRing { /* private fields */ }

A consistent hash ring for stable shard-to-node assignment.

Each physical node is represented by replicas_per_node virtual nodes spread across the ring. Adding or removing a node only relocates 1 / N of the shards on average.

Implementations

impl ConsistentHashRing

pub fn new(replicas_per_node: u32) -> Self

Create a new ring with replicas_per_node virtual nodes per physical node.

pub fn add_node(&mut self, node_id: impl Into<String>)

Add a node to the ring.

pub fn remove_node(&mut self, node_id: &str)

Remove a node from the ring.

pub fn get_node(&self, key: &ShardKey) -> Option<&str>

Find the responsible node for a shard key.

Returns None if the ring is empty.

pub fn virtual_node_count(&self) -> usize

Return the number of virtual nodes (tokens) currently in the ring.

pub fn physical_node_count(&self) -> usize

Return the number of distinct physical nodes in the ring.

pub fn nodes(&self) -> Vec<String>

List all distinct physical node IDs.

Trait Implementations

impl Debug for ConsistentHashRing

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ConsistentHashRing

fn default() -> ConsistentHashRing

Returns the “default value” for a type.