1// Copyright 2015 The etcd Authors
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15package rafthttp
16
17import (
18	"net/url"
19	"sync"
20
21	"go.etcd.io/etcd/pkg/types"
22)
23
24type urlPicker struct {
25	mu     sync.Mutex // guards urls and picked
26	urls   types.URLs
27	picked int
28}
29
30func newURLPicker(urls types.URLs) *urlPicker {
31	return &urlPicker{
32		urls: urls,
33	}
34}
35
36func (p *urlPicker) update(urls types.URLs) {
37	p.mu.Lock()
38	defer p.mu.Unlock()
39	p.urls = urls
40	p.picked = 0
41}
42
43func (p *urlPicker) pick() url.URL {
44	p.mu.Lock()
45	defer p.mu.Unlock()
46	return p.urls[p.picked]
47}
48
49// unreachable notices the picker that the given url is unreachable,
50// and it should use other possible urls.
51func (p *urlPicker) unreachable(u url.URL) {
52	p.mu.Lock()
53	defer p.mu.Unlock()
54	if u == p.urls[p.picked] {
55		p.picked = (p.picked + 1) % len(p.urls)
56	}
57}
58