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
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
|
// Package etcd provides the etcd backend.
package etcd
import (
"encoding/json"
"fmt"
"strings"
"time"
"github.com/miekg/coredns/middleware"
"github.com/miekg/coredns/middleware/etcd/msg"
"github.com/miekg/coredns/middleware/proxy"
"github.com/miekg/coredns/singleflight"
etcdc "github.com/coreos/etcd/client"
"golang.org/x/net/context"
)
type Etcd struct {
Next middleware.Handler
Zones []string
PathPrefix string
Proxy proxy.Proxy // Proxy for looking up names during the resolution process
Client etcdc.KeysAPI
Ctx context.Context
Inflight *singleflight.Group
Stubmap *map[string]proxy.Proxy // list of proxies for stub resolving.
Debug bool // Do we allow debug queries.
}
// Records looks up records in etcd. If exact is true, it will lookup just
// this name. This is used when find matches when completing SRV lookups
// for instance.
func (e *Etcd) Records(name string, exact bool) ([]msg.Service, error) {
path, star := msg.PathWithWildcard(name, e.PathPrefix)
r, err := e.Get(path, true)
if err != nil {
return nil, err
}
segments := strings.Split(msg.Path(name, e.PathPrefix), "/")
switch {
case exact && r.Node.Dir:
return nil, nil
case r.Node.Dir:
return e.loopNodes(r.Node.Nodes, segments, star, nil)
default:
return e.loopNodes([]*etcdc.Node{r.Node}, segments, false, nil)
}
}
// Get is a wrapper for client.Get that uses SingleInflight to suppress multiple outstanding queries.
func (e *Etcd) Get(path string, recursive bool) (*etcdc.Response, error) {
resp, err := e.Inflight.Do(path, func() (interface{}, error) {
ctx, cancel := context.WithTimeout(e.Ctx, etcdTimeout)
defer cancel()
r, e := e.Client.Get(ctx, path, &etcdc.GetOptions{Sort: false, Recursive: recursive})
if e != nil {
return nil, e
}
return r, e
})
if err != nil {
return nil, err
}
return resp.(*etcdc.Response), err
}
// skydns/local/skydns/east/staging/web
// skydns/local/skydns/west/production/web
//
// skydns/local/skydns/*/*/web
// skydns/local/skydns/*/web
// loopNodes recursively loops through the nodes and returns all the values. The nodes' keyname
// will be match against any wildcards when star is true.
func (e Etcd) loopNodes(ns []*etcdc.Node, nameParts []string, star bool, bx map[msg.Service]bool) (sx []msg.Service, err error) {
if bx == nil {
bx = make(map[msg.Service]bool)
}
Nodes:
for _, n := range ns {
if n.Dir {
nodes, err := e.loopNodes(n.Nodes, nameParts, star, bx)
if err != nil {
return nil, err
}
sx = append(sx, nodes...)
continue
}
if star {
keyParts := strings.Split(n.Key, "/")
for i, n := range nameParts {
if i > len(keyParts)-1 {
// name is longer than key
continue Nodes
}
if n == "*" || n == "any" {
continue
}
if keyParts[i] != n {
continue Nodes
}
}
}
serv := new(msg.Service)
if err := json.Unmarshal([]byte(n.Value), serv); err != nil {
return nil, fmt.Errorf("%s: %s", n.Key, err.Error())
}
b := msg.Service{Host: serv.Host, Port: serv.Port, Priority: serv.Priority, Weight: serv.Weight, Text: serv.Text, Key: n.Key}
if _, ok := bx[b]; ok {
continue
}
bx[b] = true
serv.Key = n.Key
serv.Ttl = e.TTL(n, serv)
if serv.Priority == 0 {
serv.Priority = priority
}
sx = append(sx, *serv)
}
return sx, nil
}
// TTL returns the smaller of the etcd TTL and the service's
// TTL. If neither of these are set (have a zero value), a default is used.
func (e *Etcd) TTL(node *etcdc.Node, serv *msg.Service) uint32 {
etcdTTL := uint32(node.TTL)
if etcdTTL == 0 && serv.Ttl == 0 {
return ttl
}
if etcdTTL == 0 {
return serv.Ttl
}
if serv.Ttl == 0 {
return etcdTTL
}
if etcdTTL < serv.Ttl {
return etcdTTL
}
return serv.Ttl
}
// etcNameError checks if the error is ErrorCodeKeyNotFound from etcd.
func isEtcdNameError(err error) bool {
if e, ok := err.(etcdc.Error); ok && e.Code == etcdc.ErrorCodeKeyNotFound {
return true
}
return false
}
const (
priority = 10 // default priority when nothing is set
ttl = 300 // default ttl when nothing is set
minTTL = 60
hostmaster = "hostmaster"
etcdTimeout = 5 * time.Second
)
|
