Trait BackendSelection 

pub trait BackendSelection: Sized {
    type Iter;
    type Config;

    // Required methods
    fn build(backends: &BTreeSet<Backend>) -> Self;
    fn iter(self: &Arc<Self>, key: &[u8]) -> Self::Iter
       where Self::Iter: BackendIter;

    // Provided method
    fn build_with_config(
        backends: &BTreeSet<Backend>,
        _config: &Self::Config,
    ) -> Self { ... }
}

BackendSelection is the interface to implement backend selection mechanisms.

Required Associated Types

type Iter

The BackendIter returned from iter() below.

type Config

The configuration type constructing BackendSelection

Required Methods

fn build(backends: &BTreeSet<Backend>) -> Self

The function to create a BackendSelection implementation.

fn iter(self: &Arc<Self>, key: &[u8]) -> Self::Iter

where Self::Iter: BackendIter,

Select backends for a given key.

An BackendIter should be returned. The first item in the iter is the first choice backend. The user should continue to iterate over it if the first backend cannot be used due to its health or other reasons.

Provided Methods

fn build_with_config( backends: &BTreeSet<Backend>, _config: &Self::Config, ) -> Self

Create a BackendSelection from a set of backends and the given configuration. The default implementation ignores the configuration and simply calls Self::build

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl BackendSelection for KetamaHashing

type Iter = OwnedNodeIterator

type Config = KetamaConfig

impl<H: SelectionAlgorithm> BackendSelection for Weighted<H>

type Iter = WeightedIterator<H>

type Config = ()