43 lines
1.5 KiB
Go
43 lines
1.5 KiB
Go
![]() |
// Copyright 2019 The etcd Authors
|
||
|
//
|
||
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
||
|
// you may not use this file except in compliance with the License.
|
||
|
// You may obtain a copy of the License at
|
||
|
//
|
||
|
// http://www.apache.org/licenses/LICENSE-2.0
|
||
|
//
|
||
|
// Unless required by applicable law or agreed to in writing, software
|
||
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
||
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
||
|
// See the License for the specific language governing permissions and
|
||
|
// limitations under the License.
|
||
|
|
||
|
package tracker
|
||
|
|
||
|
// StateType is the state of a tracked follower.
|
||
|
type StateType uint64
|
||
|
|
||
|
const (
|
||
|
// StateProbe indicates a follower whose last index isn't known. Such a
|
||
|
// follower is "probed" (i.e. an append sent periodically) to narrow down
|
||
|
// its last index. In the ideal (and common) case, only one round of probing
|
||
|
// is necessary as the follower will react with a hint. Followers that are
|
||
|
// probed over extended periods of time are often offline.
|
||
|
StateProbe StateType = iota
|
||
|
// StateReplicate is the state steady in which a follower eagerly receives
|
||
|
// log entries to append to its log.
|
||
|
StateReplicate
|
||
|
// StateSnapshot indicates a follower that needs log entries not available
|
||
|
// from the leader's Raft log. Such a follower needs a full snapshot to
|
||
|
// return to StateReplicate.
|
||
|
StateSnapshot
|
||
|
)
|
||
|
|
||
|
var prstmap = [...]string{
|
||
|
"StateProbe",
|
||
|
"StateReplicate",
|
||
|
"StateSnapshot",
|
||
|
}
|
||
|
|
||
|
func (st StateType) String() string { return prstmap[uint64(st)] }
|