Trait Strategy 

pub trait Strategy: Send + Sync {
    // Required methods
    fn name(&self) -> &'static str;
    fn desired_replicas(
        &self,
        state: &ClusterState,
        now: Timestamp,
    ) -> Vec<DesiredReplica>;

    // Provided method
    fn update_state(&self, _state: &ClusterState, _now: Timestamp) -> StateWrite { ... }
}

One cluster-autoscaling strategy: a pair of pure functions the controller runs each tick. See the module docs.

Send + Sync so the controller (which holds a set of boxed strategies) can run on its own task.

Required Methods

fn name(&self) -> &'static str

A stable identifier used in audit attribution (which strategies desired a create; drops carry no attribution).

fn desired_replicas( &self, state: &ClusterState, now: Timestamp, ) -> Vec<DesiredReplica>

The replica slots this strategy contributes to state’s desired set at time now.

Provided Methods

fn update_state(&self, _state: &ClusterState, _now: Timestamp) -> StateWrite

The durable writes this strategy wants for state at time now. The default is no write, which suits a strategy that only ever contributes replicas (like the baseline).

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl Strategy for BaselineStrategy