forked from CodisLabs/codis
-
Notifications
You must be signed in to change notification settings - Fork 0
/
backend.go
271 lines (236 loc) · 5.11 KB
/
backend.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
// Copyright 2014 Wandoujia Inc. All Rights Reserved.
// Licensed under the MIT (MIT-LICENSE.txt) license.
package router
import (
"fmt"
"sync"
"time"
"github.com/wandoulabs/codis/pkg/proxy/redis"
"github.com/wandoulabs/codis/pkg/utils/errors"
"github.com/wandoulabs/codis/pkg/utils/log"
)
type BackendConn struct {
addr string
auth string
stop sync.Once
input chan *Request
}
func NewBackendConn(addr, auth string) *BackendConn {
bc := &BackendConn{
addr: addr, auth: auth,
input: make(chan *Request, 1024),
}
go bc.Run()
return bc
}
func (bc *BackendConn) Run() {
log.Infof("backend conn [%p] to %s, start service", bc, bc.addr)
for k := 0; ; k++ {
err := bc.loopWriter()
if err == nil {
break
} else {
for i := len(bc.input); i != 0; i-- {
r := <-bc.input
bc.setResponse(r, nil, err)
}
}
log.WarnErrorf(err, "backend conn [%p] to %s, restart [%d]", bc, bc.addr, k)
time.Sleep(time.Millisecond * 50)
}
log.Infof("backend conn [%p] to %s, stop and exit", bc, bc.addr)
}
func (bc *BackendConn) Addr() string {
return bc.addr
}
func (bc *BackendConn) Close() {
bc.stop.Do(func() {
close(bc.input)
})
}
func (bc *BackendConn) PushBack(r *Request) {
if r.Wait != nil {
r.Wait.Add(1)
}
bc.input <- r
}
func (bc *BackendConn) KeepAlive() bool {
if len(bc.input) != 0 {
return false
}
r := &Request{
Resp: redis.NewArray([]*redis.Resp{
redis.NewBulkBytes([]byte("PING")),
}),
}
select {
case bc.input <- r:
return true
default:
return false
}
}
var ErrFailedRequest = errors.New("discard failed request")
func (bc *BackendConn) loopWriter() error {
r, ok := <-bc.input
if ok {
c, tasks, err := bc.newBackendReader()
if err != nil {
return bc.setResponse(r, nil, err)
}
defer close(tasks)
p := &FlushPolicy{
Encoder: c.Writer,
MaxBuffered: 64,
MaxInterval: 300,
}
for ok {
var flush = len(bc.input) == 0
if bc.canForward(r) {
if err := p.Encode(r.Resp, flush); err != nil {
return bc.setResponse(r, nil, err)
}
tasks <- r
} else {
if err := p.Flush(flush); err != nil {
return bc.setResponse(r, nil, err)
}
bc.setResponse(r, nil, ErrFailedRequest)
}
r, ok = <-bc.input
}
}
return nil
}
func (bc *BackendConn) newBackendReader() (*redis.Conn, chan<- *Request, error) {
c, err := redis.DialTimeout(bc.addr, 1024*512, time.Second)
if err != nil {
return nil, nil, err
}
c.ReaderTimeout = time.Minute
c.WriterTimeout = time.Minute
if err := bc.verifyAuth(c); err != nil {
c.Close()
return nil, nil, err
}
tasks := make(chan *Request, 4096)
go func() {
defer c.Close()
for r := range tasks {
resp, err := c.Reader.Decode()
bc.setResponse(r, resp, err)
}
}()
return c, tasks, nil
}
func (bc *BackendConn) verifyAuth(c *redis.Conn) error {
if bc.auth == "" {
return nil
}
resp := redis.NewArray([]*redis.Resp{
redis.NewBulkBytes([]byte("AUTH")),
redis.NewBulkBytes([]byte(bc.auth)),
})
if err := c.Writer.Encode(resp, true); err != nil {
return err
}
resp, err := c.Reader.Decode()
if err != nil {
return err
}
if resp == nil {
return errors.New(fmt.Sprintf("error resp: nil response"))
}
if resp.IsError() {
return errors.New(fmt.Sprintf("error resp: %s", resp.Value))
}
if resp.IsString() {
return nil
} else {
return errors.New(fmt.Sprintf("error resp: should be string, but got %s", resp.Type))
}
}
func (bc *BackendConn) canForward(r *Request) bool {
if r.Failed != nil && r.Failed.Get() {
return false
} else {
return true
}
}
func (bc *BackendConn) setResponse(r *Request, resp *redis.Resp, err error) error {
r.Response.Resp, r.Response.Err = resp, err
if err != nil && r.Failed != nil {
r.Failed.Set(true)
}
if r.Wait != nil {
r.Wait.Done()
}
if r.slot != nil {
r.slot.Done()
}
return err
}
type SharedBackendConn struct {
*BackendConn
mu sync.Mutex
refcnt int
}
func NewSharedBackendConn(addr, auth string) *SharedBackendConn {
return &SharedBackendConn{BackendConn: NewBackendConn(addr, auth), refcnt: 1}
}
func (s *SharedBackendConn) Close() bool {
s.mu.Lock()
defer s.mu.Unlock()
if s.refcnt <= 0 {
log.Panicf("shared backend conn has been closed, close too many times")
}
if s.refcnt == 1 {
s.BackendConn.Close()
}
s.refcnt--
return s.refcnt == 0
}
func (s *SharedBackendConn) IncrRefcnt() {
s.mu.Lock()
defer s.mu.Unlock()
if s.refcnt == 0 {
log.Panicf("shared backend conn has been closed")
}
s.refcnt++
}
type FlushPolicy struct {
*redis.Encoder
MaxBuffered int
MaxInterval int64
nbuffered int
lastflush int64
}
func (p *FlushPolicy) needFlush() bool {
if p.nbuffered != 0 {
if p.nbuffered > p.MaxBuffered {
return true
}
if microseconds()-p.lastflush > p.MaxInterval {
return true
}
}
return false
}
func (p *FlushPolicy) Flush(force bool) error {
if force || p.needFlush() {
if err := p.Encoder.Flush(); err != nil {
return err
}
p.nbuffered = 0
p.lastflush = microseconds()
}
return nil
}
func (p *FlushPolicy) Encode(resp *redis.Resp, force bool) error {
if err := p.Encoder.Encode(resp, false); err != nil {
return err
} else {
p.nbuffered++
return p.Flush(force)
}
}