forked from kubernetes/kubernetes
-
Notifications
You must be signed in to change notification settings - Fork 14
/
discovery.go
355 lines (320 loc) · 9.75 KB
/
discovery.go
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
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
// Copyright 2015 CoreOS, Inc.
//
// 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 discovery
import (
"errors"
"fmt"
"math"
"net"
"net/http"
"net/url"
"path"
"sort"
"strconv"
"strings"
"time"
"github.com/coreos/etcd/client"
"github.com/coreos/etcd/pkg/types"
"github.com/coreos/pkg/capnslog"
"github.com/jonboulle/clockwork"
"golang.org/x/net/context"
)
var (
plog = capnslog.NewPackageLogger("github.com/coreos/etcd", "discovery")
ErrInvalidURL = errors.New("discovery: invalid URL")
ErrBadSizeKey = errors.New("discovery: size key is bad")
ErrSizeNotFound = errors.New("discovery: size key not found")
ErrTokenNotFound = errors.New("discovery: token not found")
ErrDuplicateID = errors.New("discovery: found duplicate id")
ErrDuplicateName = errors.New("discovery: found duplicate name")
ErrFullCluster = errors.New("discovery: cluster is full")
ErrTooManyRetries = errors.New("discovery: too many retries")
ErrBadDiscoveryEndpoint = errors.New("discovery: bad discovery endpoint")
)
var (
// Number of retries discovery will attempt before giving up and erroring out.
nRetries = uint(math.MaxUint32)
)
// JoinCluster will connect to the discovery service at the given url, and
// register the server represented by the given id and config to the cluster
func JoinCluster(durl, dproxyurl string, id types.ID, config string) (string, error) {
d, err := newDiscovery(durl, dproxyurl, id)
if err != nil {
return "", err
}
return d.joinCluster(config)
}
// GetCluster will connect to the discovery service at the given url and
// retrieve a string describing the cluster
func GetCluster(durl, dproxyurl string) (string, error) {
d, err := newDiscovery(durl, dproxyurl, 0)
if err != nil {
return "", err
}
return d.getCluster()
}
type discovery struct {
cluster string
id types.ID
c client.KeysAPI
retries uint
url *url.URL
clock clockwork.Clock
}
// newProxyFunc builds a proxy function from the given string, which should
// represent a URL that can be used as a proxy. It performs basic
// sanitization of the URL and returns any error encountered.
func newProxyFunc(proxy string) (func(*http.Request) (*url.URL, error), error) {
if proxy == "" {
return nil, nil
}
// Do a small amount of URL sanitization to help the user
// Derived from net/http.ProxyFromEnvironment
proxyURL, err := url.Parse(proxy)
if err != nil || !strings.HasPrefix(proxyURL.Scheme, "http") {
// proxy was bogus. Try prepending "http://" to it and
// see if that parses correctly. If not, we ignore the
// error and complain about the original one
var err2 error
proxyURL, err2 = url.Parse("http://" + proxy)
if err2 == nil {
err = nil
}
}
if err != nil {
return nil, fmt.Errorf("invalid proxy address %q: %v", proxy, err)
}
plog.Infof("using proxy %q", proxyURL.String())
return http.ProxyURL(proxyURL), nil
}
func newDiscovery(durl, dproxyurl string, id types.ID) (*discovery, error) {
u, err := url.Parse(durl)
if err != nil {
return nil, err
}
token := u.Path
u.Path = ""
pf, err := newProxyFunc(dproxyurl)
if err != nil {
return nil, err
}
cfg := client.Config{
Transport: &http.Transport{
Proxy: pf,
Dial: (&net.Dialer{
Timeout: 30 * time.Second,
KeepAlive: 30 * time.Second,
}).Dial,
TLSHandshakeTimeout: 10 * time.Second,
// TODO: add ResponseHeaderTimeout back when watch on discovery service writes header early
},
Endpoints: []string{u.String()},
}
c, err := client.New(cfg)
if err != nil {
return nil, err
}
dc := client.NewKeysAPIWithPrefix(c, "")
return &discovery{
cluster: token,
c: dc,
id: id,
url: u,
clock: clockwork.NewRealClock(),
}, nil
}
func (d *discovery) joinCluster(config string) (string, error) {
// fast path: if the cluster is full, return the error
// do not need to register to the cluster in this case.
if _, _, _, err := d.checkCluster(); err != nil {
return "", err
}
if err := d.createSelf(config); err != nil {
// Fails, even on a timeout, if createSelf times out.
// TODO(barakmich): Retrying the same node might want to succeed here
// (ie, createSelf should be idempotent for discovery).
return "", err
}
nodes, size, index, err := d.checkCluster()
if err != nil {
return "", err
}
all, err := d.waitNodes(nodes, size, index)
if err != nil {
return "", err
}
return nodesToCluster(all, size)
}
func (d *discovery) getCluster() (string, error) {
nodes, size, index, err := d.checkCluster()
if err != nil {
if err == ErrFullCluster {
return nodesToCluster(nodes, size)
}
return "", err
}
all, err := d.waitNodes(nodes, size, index)
if err != nil {
return "", err
}
return nodesToCluster(all, size)
}
func (d *discovery) createSelf(contents string) error {
ctx, cancel := context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
resp, err := d.c.Create(ctx, d.selfKey(), contents)
cancel()
if err != nil {
if eerr, ok := err.(client.Error); ok && eerr.Code == client.ErrorCodeNodeExist {
return ErrDuplicateID
}
return err
}
// ensure self appears on the server we connected to
w := d.c.Watcher(d.selfKey(), &client.WatcherOptions{AfterIndex: resp.Node.CreatedIndex - 1})
_, err = w.Next(context.Background())
return err
}
func (d *discovery) checkCluster() ([]*client.Node, int, uint64, error) {
configKey := path.Join("/", d.cluster, "_config")
ctx, cancel := context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
// find cluster size
resp, err := d.c.Get(ctx, path.Join(configKey, "size"), nil)
cancel()
if err != nil {
if eerr, ok := err.(*client.Error); ok && eerr.Code == client.ErrorCodeKeyNotFound {
return nil, 0, 0, ErrSizeNotFound
}
if err == client.ErrInvalidJSON {
return nil, 0, 0, ErrBadDiscoveryEndpoint
}
if ce, ok := err.(*client.ClusterError); ok {
plog.Error(ce.Detail())
return d.checkClusterRetry()
}
return nil, 0, 0, err
}
size, err := strconv.Atoi(resp.Node.Value)
if err != nil {
return nil, 0, 0, ErrBadSizeKey
}
ctx, cancel = context.WithTimeout(context.Background(), client.DefaultRequestTimeout)
resp, err = d.c.Get(ctx, d.cluster, nil)
cancel()
if err != nil {
if ce, ok := err.(*client.ClusterError); ok {
plog.Error(ce.Detail())
return d.checkClusterRetry()
}
return nil, 0, 0, err
}
nodes := make([]*client.Node, 0)
// append non-config keys to nodes
for _, n := range resp.Node.Nodes {
if !(path.Base(n.Key) == path.Base(configKey)) {
nodes = append(nodes, n)
}
}
snodes := sortableNodes{nodes}
sort.Sort(snodes)
// find self position
for i := range nodes {
if path.Base(nodes[i].Key) == path.Base(d.selfKey()) {
break
}
if i >= size-1 {
return nodes[:size], size, resp.Index, ErrFullCluster
}
}
return nodes, size, resp.Index, nil
}
func (d *discovery) logAndBackoffForRetry(step string) {
d.retries++
retryTime := time.Second * (0x1 << d.retries)
plog.Infof("%s: error connecting to %s, retrying in %s", step, d.url, retryTime)
d.clock.Sleep(retryTime)
}
func (d *discovery) checkClusterRetry() ([]*client.Node, int, uint64, error) {
if d.retries < nRetries {
d.logAndBackoffForRetry("cluster status check")
return d.checkCluster()
}
return nil, 0, 0, ErrTooManyRetries
}
func (d *discovery) waitNodesRetry() ([]*client.Node, error) {
if d.retries < nRetries {
d.logAndBackoffForRetry("waiting for other nodes")
nodes, n, index, err := d.checkCluster()
if err != nil {
return nil, err
}
return d.waitNodes(nodes, n, index)
}
return nil, ErrTooManyRetries
}
func (d *discovery) waitNodes(nodes []*client.Node, size int, index uint64) ([]*client.Node, error) {
if len(nodes) > size {
nodes = nodes[:size]
}
// watch from the next index
w := d.c.Watcher(d.cluster, &client.WatcherOptions{AfterIndex: index, Recursive: true})
all := make([]*client.Node, len(nodes))
copy(all, nodes)
for _, n := range all {
if path.Base(n.Key) == path.Base(d.selfKey()) {
plog.Noticef("found self %s in the cluster", path.Base(d.selfKey()))
} else {
plog.Noticef("found peer %s in the cluster", path.Base(n.Key))
}
}
// wait for others
for len(all) < size {
plog.Noticef("found %d peer(s), waiting for %d more", len(all), size-len(all))
resp, err := w.Next(context.Background())
if err != nil {
if ce, ok := err.(*client.ClusterError); ok {
plog.Error(ce.Detail())
return d.waitNodesRetry()
}
return nil, err
}
plog.Noticef("found peer %s in the cluster", path.Base(resp.Node.Key))
all = append(all, resp.Node)
}
plog.Noticef("found %d needed peer(s)", len(all))
return all, nil
}
func (d *discovery) selfKey() string {
return path.Join("/", d.cluster, d.id.String())
}
func nodesToCluster(ns []*client.Node, size int) (string, error) {
s := make([]string, len(ns))
for i, n := range ns {
s[i] = n.Value
}
us := strings.Join(s, ",")
m, err := types.NewURLsMap(us)
if err != nil {
return us, ErrInvalidURL
}
if m.Len() != size {
return us, ErrDuplicateName
}
return us, nil
}
type sortableNodes struct{ Nodes []*client.Node }
func (ns sortableNodes) Len() int { return len(ns.Nodes) }
func (ns sortableNodes) Less(i, j int) bool {
return ns.Nodes[i].CreatedIndex < ns.Nodes[j].CreatedIndex
}
func (ns sortableNodes) Swap(i, j int) { ns.Nodes[i], ns.Nodes[j] = ns.Nodes[j], ns.Nodes[i] }