Trait raft_consensus::state_machine::StateMachine [−] [src]

pub trait StateMachine: Debug + Send + 'static {
    fn apply(&mut self, command: &[u8]) -> Vec<u8>;

    fn query(&self, query: &[u8]) -> Vec<u8>;

    fn snapshot(&self) -> Vec<u8>;

    fn restore_snapshot(&mut self, snapshot: Vec<u8>);
}

This trait is meant to be implemented such that the commands issued to it via apply() will be reflected in your consuming application. Commands sent via apply() have been committed in the cluser. Unlike store, your application should consume data produced by this and accept it as truth.

Note that you are responsible for not crashing the state machine. Your production implementation should not use .unwrap(), .expect() or anything else that likes to panic!()

Required Methods

Applies a command to the state machine. Returns an application-specific result value.

Queries a value of the state machine. Does not go through the durable log, or mutate the state machine. Returns an application-specific result value.

Take a snapshot of the state machine.

Restore a snapshot of the state machine.

Implementors