1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
// Copyright 2017 Canonical Ltd.
//
// 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 election
import (
"fmt"
"time"
"github.com/hashicorp/raft"
)
// Future represents a request to acquire leadership that will eventually
// succeed or fail.
type Future struct {
// ID of the raft server that should acquire leadership.
id raft.ServerID
// If leadership is not acquire within this timeout, the future fails.
timeout time.Duration
// Notification about leadership being acquired.
acquiredCh chan struct{}
// Notification about leadership being lost.
lostCh chan struct{}
}
// Creates a new leadership future of the given server.
func newFuture(id raft.ServerID, timeout time.Duration) *Future {
future := &Future{
id: id,
timeout: timeout,
acquiredCh: make(chan struct{}),
lostCh: make(chan struct{}),
}
return future
}
// Done returns a Leadership object if leadership was acquired withing the
// timeout, or an error otherwise.
func (f *Future) Done() (*Leadership, error) {
select {
case <-f.acquiredCh:
leadership := newLeadership(f.id, f.lostCh)
return leadership, nil
case <-time.After(f.timeout):
return nil, fmt.Errorf("server %s: leadership not acquired within %s", f.id, f.timeout)
}
}
|
