forked from coreos/fleet
-
Notifications
You must be signed in to change notification settings - Fork 1
/
event.go
101 lines (83 loc) · 2 KB
/
event.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
package registry
import (
"path"
"strings"
"time"
"github.com/coreos/fleet/etcd"
"github.com/coreos/fleet/log"
"github.com/coreos/fleet/pkg"
)
const (
// Occurs when any Job's target is touched
JobTargetChangeEvent = pkg.Event("JobTargetChangeEvent")
// Occurs when any Job's target state is touched
JobTargetStateChangeEvent = pkg.Event("JobTargetStateChangeEvent")
)
type etcdEventStream struct {
etcd etcd.Client
rootPrefix string
}
func NewEtcdEventStream(client etcd.Client, rootPrefix string) pkg.EventStream {
return &etcdEventStream{client, rootPrefix}
}
// Next returns a channel which will emit an Event as soon as one of interest occurs
func (es *etcdEventStream) Next(stop chan struct{}) chan pkg.Event {
evchan := make(chan pkg.Event)
go func() {
for {
select {
case <-stop:
return
default:
}
res := watch(es.etcd, path.Join(es.rootPrefix, jobPrefix), stop)
if ev, ok := parse(res, es.rootPrefix); ok {
evchan <- ev
return
}
}
}()
return evchan
}
func parse(res *etcd.Result, prefix string) (ev pkg.Event, ok bool) {
if res == nil || res.Node == nil {
return
}
if !strings.HasPrefix(res.Node.Key, path.Join(prefix, jobPrefix)) {
return
}
switch path.Base(res.Node.Key) {
case "target-state":
ev = JobTargetStateChangeEvent
ok = true
case "target":
ev = JobTargetChangeEvent
ok = true
}
return
}
func watch(client etcd.Client, key string, stop chan struct{}) (res *etcd.Result) {
for res == nil {
select {
case <-stop:
log.V(1).Infof("Gracefully closing etcd watch loop: key=%s", key)
return
default:
req := &etcd.Watch{
Key: key,
WaitIndex: 0,
Recursive: true,
}
log.V(1).Infof("Creating etcd watcher: %v", req)
var err error
res, err = client.Wait(req, stop)
if err != nil {
log.Errorf("etcd watcher %v returned error: %v", req, err)
}
}
// Let's not slam the etcd server in the event that we know
// an unexpected error occurred.
time.Sleep(time.Second)
}
return
}