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
|
package pool
import (
"context"
"errors"
"fmt"
"sync/atomic"
)
const (
stateDefault = 0
stateInited = 1
stateClosed = 2
)
type BadConnError struct {
wrapped error
}
var _ error = (*BadConnError)(nil)
func (e BadConnError) Error() string {
s := "redis: Conn is in a bad state"
if e.wrapped != nil {
s += ": " + e.wrapped.Error()
}
return s
}
func (e BadConnError) Unwrap() error {
return e.wrapped
}
//------------------------------------------------------------------------------
type StickyConnPool struct {
pool Pooler
shared int32 // atomic
state uint32 // atomic
ch chan *Conn
_badConnError atomic.Value
}
var _ Pooler = (*StickyConnPool)(nil)
func NewStickyConnPool(pool Pooler) *StickyConnPool {
p, ok := pool.(*StickyConnPool)
if !ok {
p = &StickyConnPool{
pool: pool,
ch: make(chan *Conn, 1),
}
}
atomic.AddInt32(&p.shared, 1)
return p
}
func (p *StickyConnPool) NewConn(ctx context.Context) (*Conn, error) {
return p.pool.NewConn(ctx)
}
func (p *StickyConnPool) CloseConn(cn *Conn) error {
return p.pool.CloseConn(cn)
}
func (p *StickyConnPool) Get(ctx context.Context) (*Conn, error) {
// In worst case this races with Close which is not a very common operation.
for i := 0; i < 1000; i++ {
switch atomic.LoadUint32(&p.state) {
case stateDefault:
cn, err := p.pool.Get(ctx)
if err != nil {
return nil, err
}
if atomic.CompareAndSwapUint32(&p.state, stateDefault, stateInited) {
return cn, nil
}
p.pool.Remove(ctx, cn, ErrClosed)
case stateInited:
if err := p.badConnError(); err != nil {
return nil, err
}
cn, ok := <-p.ch
if !ok {
return nil, ErrClosed
}
return cn, nil
case stateClosed:
return nil, ErrClosed
default:
panic("not reached")
}
}
return nil, fmt.Errorf("redis: StickyConnPool.Get: infinite loop")
}
func (p *StickyConnPool) Put(ctx context.Context, cn *Conn) {
defer func() {
if recover() != nil {
p.freeConn(ctx, cn)
}
}()
p.ch <- cn
}
func (p *StickyConnPool) freeConn(ctx context.Context, cn *Conn) {
if err := p.badConnError(); err != nil {
p.pool.Remove(ctx, cn, err)
} else {
p.pool.Put(ctx, cn)
}
}
func (p *StickyConnPool) Remove(ctx context.Context, cn *Conn, reason error) {
defer func() {
if recover() != nil {
p.pool.Remove(ctx, cn, ErrClosed)
}
}()
p._badConnError.Store(BadConnError{wrapped: reason})
p.ch <- cn
}
func (p *StickyConnPool) Close() error {
if shared := atomic.AddInt32(&p.shared, -1); shared > 0 {
return nil
}
for i := 0; i < 1000; i++ {
state := atomic.LoadUint32(&p.state)
if state == stateClosed {
return ErrClosed
}
if atomic.CompareAndSwapUint32(&p.state, state, stateClosed) {
close(p.ch)
cn, ok := <-p.ch
if ok {
p.freeConn(context.TODO(), cn)
}
return nil
}
}
return errors.New("redis: StickyConnPool.Close: infinite loop")
}
func (p *StickyConnPool) Reset(ctx context.Context) error {
if p.badConnError() == nil {
return nil
}
select {
case cn, ok := <-p.ch:
if !ok {
return ErrClosed
}
p.pool.Remove(ctx, cn, ErrClosed)
p._badConnError.Store(BadConnError{wrapped: nil})
default:
return errors.New("redis: StickyConnPool does not have a Conn")
}
if !atomic.CompareAndSwapUint32(&p.state, stateInited, stateDefault) {
state := atomic.LoadUint32(&p.state)
return fmt.Errorf("redis: invalid StickyConnPool state: %d", state)
}
return nil
}
func (p *StickyConnPool) badConnError() error {
if v := p._badConnError.Load(); v != nil {
if err := v.(BadConnError); err.wrapped != nil {
return err
}
}
return nil
}
func (p *StickyConnPool) Len() int {
switch atomic.LoadUint32(&p.state) {
case stateDefault:
return 0
case stateInited:
return 1
case stateClosed:
return 0
default:
panic("not reached")
}
}
func (p *StickyConnPool) IdleLen() int {
return len(p.ch)
}
func (p *StickyConnPool) Stats() *Stats {
return &Stats{}
}
|
