Struct Continuum 

pub struct Continuum { /* private fields */ }

Sorted continuum, ready for dispatch.

Examples

use dynomite::hashkit::ketama::{Continuum, ServerSpec};
use dynomite::hashkit::DynToken;
let c = Continuum::build(&[
    ServerSpec { name: "a".into(), weight: 1 },
    ServerSpec { name: "b".into(), weight: 1 },
]).unwrap();
assert!(!c.is_empty());
let _ = c.dispatch(&DynToken::from_u32(123)).unwrap();

Implementations

impl Continuum

pub fn build(servers: &[ServerSpec]) -> Result<Self, DynError>

Build the continuum for the supplied servers.

Errors

Returns DynError::Generic when a server’s name + index would overflow the MAX_HOSTLEN buffer.

Examples

use dynomite::hashkit::ketama::{Continuum, ServerSpec, POINTS_PER_SERVER};
let c = Continuum::build(&[ServerSpec { name: "s0".into(), weight: 1 }]).unwrap();
assert_eq!(c.len(), POINTS_PER_SERVER as usize);

pub fn len(&self) -> usize

Number of continuum points.

Examples

use dynomite::hashkit::ketama::Continuum;
assert_eq!(Continuum::default().len(), 0);

pub fn is_empty(&self) -> bool

Whether the continuum is empty.

Examples

use dynomite::hashkit::ketama::Continuum;
assert!(Continuum::default().is_empty());

pub fn points(&self) -> &[ContinuumPoint]

Read-only view of the continuum points, in sorted order.

Examples

use dynomite::hashkit::ketama::{Continuum, ServerSpec};
let c = Continuum::build(&[ServerSpec { name: "a".into(), weight: 1 }]).unwrap();
let pts = c.points();
assert!(pts.windows(2).all(|w| w[0].token <= w[1].token));

pub fn dispatch(&self, hash: &DynToken) -> Result<usize, DynError>

Map a hash value to the owning server index.

Walks the continuum with a binary search and wraps around when the requested token sorts after the last point.

Errors

Returns an error if the continuum is empty.

Examples

use dynomite::hashkit::ketama::{Continuum, ServerSpec};
use dynomite::hashkit::DynToken;
let c = Continuum::build(&[
    ServerSpec { name: "a".into(), weight: 1 },
    ServerSpec { name: "b".into(), weight: 1 },
]).unwrap();
let s = c.dispatch(&DynToken::from_u32(0xabcd)).unwrap();
assert!(s < 2);
assert!(Continuum::default().dispatch(&DynToken::from_u32(0)).is_err());

Trait Implementations

impl Clone for Continuum

fn clone(&self) -> Continuum

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Continuum

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

Formats the value using the given formatter.

impl Default for Continuum

fn default() -> Continuum

Returns the “default value” for a type.