mirror of https://github.com/hashicorp/consul
38 lines
1.3 KiB
Go
38 lines
1.3 KiB
Go
package raft
|
|
|
|
import (
|
|
"io"
|
|
)
|
|
|
|
// FSM provides an interface that can be implemented by
|
|
// clients to make use of the replicated log.
|
|
type FSM interface {
|
|
// Apply log is invoked once a log entry is committed.
|
|
Apply(*Log) interface{}
|
|
|
|
// Snapshot is used to support log compaction. This call should
|
|
// return an FSMSnapshot which can be used to save a point-in-time
|
|
// snapshot of the FSM. Apply and Snapshot are not called in multiple
|
|
// threads, but Apply will be called concurrently with Persist. This means
|
|
// the FSM should be implemented in a fashion that allows for concurrent
|
|
// updates while a snapshot is happening.
|
|
Snapshot() (FSMSnapshot, error)
|
|
|
|
// Restore is used to restore an FSM from a snapshot. It is not called
|
|
// concurrently with any other command. The FSM must discard all previous
|
|
// state.
|
|
Restore(io.ReadCloser) error
|
|
}
|
|
|
|
// FSMSnapshot is returned by an FSM in response to a Snapshot
|
|
// It must be safe to invoke FSMSnapshot methods with concurrent
|
|
// calls to Apply.
|
|
type FSMSnapshot interface {
|
|
// Persist should dump all necessary state to the WriteCloser 'sink',
|
|
// and call sink.Close() when finished or call sink.Cancel() on error.
|
|
Persist(sink SnapshotSink) error
|
|
|
|
// Release is invoked when we are finished with the snapshot.
|
|
Release()
|
|
}
|