forked from cloudfoundry/locket
/
lock.go
165 lines (146 loc) · 4.13 KB
/
lock.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
package lock
import (
"os"
"time"
"code.cloudfoundry.org/clock"
"code.cloudfoundry.org/lager/v3"
"code.cloudfoundry.org/locket/models"
uuid "github.com/nu7hatch/gouuid"
"github.com/pkg/errors"
"golang.org/x/net/context"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/metadata"
)
type lockRunner struct {
logger lager.Logger
locker models.LocketClient
lock *models.Resource
ttlInSeconds int64
clock clock.Clock
retryInterval time.Duration
exitOnLostLock bool
}
func NewLockRunner(
logger lager.Logger,
locker models.LocketClient,
lock *models.Resource,
ttlInSeconds int64,
clock clock.Clock,
retryInterval time.Duration,
) *lockRunner {
return &lockRunner{
logger: logger,
locker: locker,
lock: lock,
ttlInSeconds: ttlInSeconds,
clock: clock,
retryInterval: retryInterval,
exitOnLostLock: true,
}
}
func NewPresenceRunner(
logger lager.Logger,
locker models.LocketClient,
lock *models.Resource,
ttlInSeconds int64,
clock clock.Clock,
retryInterval time.Duration,
) *lockRunner {
return &lockRunner{
logger: logger,
locker: locker,
lock: lock,
ttlInSeconds: ttlInSeconds,
clock: clock,
retryInterval: retryInterval,
exitOnLostLock: false,
}
}
func contextWithRequestGUID() (context.Context, string, error) {
ctx := context.Background()
uuid, err := uuid.NewV4()
if err != nil {
return ctx, "", err
}
md := metadata.Pairs("uuid", uuid.String())
return metadata.NewOutgoingContext(ctx, md), uuid.String(), nil
}
func (l *lockRunner) Run(signals <-chan os.Signal, ready chan<- struct{}) error {
logger := l.logger.Session("locket-lock", lager.Data{"lock": l.lock, "ttl_in_seconds": l.ttlInSeconds})
logger.Info("started")
defer logger.Info("completed")
var acquired, isReady bool
ctx, uuid, err := contextWithRequestGUID()
if err != nil {
logger.Error("failed-to-create-context", err)
return err
}
_, err = l.locker.Lock(ctx, &models.LockRequest{Resource: l.lock, TtlInSeconds: l.ttlInSeconds})
if err != nil {
lagerData := lager.Data{"request-uuid": uuid}
resp, fErr := l.locker.Fetch(ctx, &models.FetchRequest{Key: l.lock.Key})
if fErr != nil {
logger.Error("failed-fetching-lock-owner", fErr)
} else {
lagerData["lock-owner"] = resp.Resource.Owner
}
logger.Error("failed-to-acquire-lock", err, lagerData)
} else {
logger.Info("acquired-lock")
close(ready)
acquired = true
isReady = true
}
retry := l.clock.NewTimer(l.retryInterval)
for {
select {
case sig := <-signals:
logger.Info("signalled", lager.Data{"signal": sig})
_, err := l.locker.Release(context.Background(), &models.ReleaseRequest{Resource: l.lock})
if err != nil {
logger.Error("failed-to-release-lock", err)
} else {
logger.Info("released-lock")
}
return nil
case <-retry.C():
ctx, uuid, err := contextWithRequestGUID()
if err != nil {
logger.Error("failed-to-create-context", err)
return err
}
ctx, cancel := context.WithTimeout(ctx, time.Duration(l.ttlInSeconds)*time.Second)
start := time.Now()
_, err = l.locker.Lock(ctx, &models.LockRequest{Resource: l.lock, TtlInSeconds: l.ttlInSeconds}, grpc.FailFast(false))
cancel()
if err != nil {
if acquired {
logger.Error("lost-lock", err, lager.Data{"request-uuid": uuid, "duration": time.Since(start)})
if l.exitOnLostLock {
return newLockLostError(err, uuid)
}
acquired = false
} else if grpc.Code(err) != grpc.Code(models.ErrLockCollision) {
logger.Error("failed-to-acquire-lock", err, lager.Data{"request-uuid": uuid, "duration": time.Since(start)})
}
} else if !acquired {
logger.Info("acquired-lock")
if !isReady {
close(ready)
isReady = true
}
acquired = true
}
retry.Reset(l.retryInterval)
}
}
}
func newLockLostError(err error, requestUUID string) error {
additionalMessage := "request failed"
switch grpc.Code(err) {
case codes.DeadlineExceeded:
additionalMessage = "request timed out"
}
return errors.Wrapf(err, "lost lock (%s), request-uuid %s", additionalMessage, requestUUID)
}