-
Notifications
You must be signed in to change notification settings - Fork 1
/
subscriber.go
172 lines (142 loc) · 4.33 KB
/
subscriber.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
package nats_broker
import (
"context"
"fmt"
"git.golaxy.org/core/util/generic"
"git.golaxy.org/plugins/broker"
"git.golaxy.org/plugins/log"
"github.com/nats-io/nats.go"
"strings"
)
type _SubscribeMode int32
const (
_SubscribeMode_Handler _SubscribeMode = iota
_SubscribeMode_Sync
_SubscribeMode_Chan
)
func (b *_Broker) newSubscriber(ctx context.Context, mode _SubscribeMode, pattern string, opts broker.SubscriberOptions) (*_Subscriber, error) {
if ctx == nil {
ctx = context.Background()
}
if b.options.TopicPrefix != "" {
pattern = b.options.TopicPrefix + pattern
}
ctx, cancel := context.WithCancel(ctx)
sub := &_Subscriber{
Context: ctx,
cancel: cancel,
stoppedChan: make(chan struct{}),
broker: b,
unsubscribedHandler: opts.UnsubscribedHandler,
}
var handleMsg nats.MsgHandler
switch mode {
case _SubscribeMode_Sync, _SubscribeMode_Chan:
sub.eventChan = make(chan broker.IEvent, opts.EventChanSize)
handleMsg = sub.handleEventChan
case _SubscribeMode_Handler:
sub.eventHandler = opts.EventHandler
handleMsg = sub.handleEventProcess
}
var err error
if opts.Queue != "" {
queue := opts.Queue
if b.options.QueuePrefix != "" {
queue = b.options.QueuePrefix + queue
}
sub.natsSub, err = b.client.QueueSubscribe(pattern, queue, handleMsg)
} else {
sub.natsSub, err = b.client.Subscribe(pattern, handleMsg)
}
if err != nil {
return nil, fmt.Errorf("%w: %w", broker.ErrBroker, err)
}
log.Debugf(b.servCtx, "subscribe topic pattern %q queue %q success", sub.Queue(), sub.Queue())
b.wg.Add(1)
go sub.mainLoop()
return sub, nil
}
type _Subscriber struct {
context.Context
cancel context.CancelFunc
stoppedChan chan struct{}
broker *_Broker
natsSub *nats.Subscription
eventChan chan broker.IEvent
eventHandler broker.EventHandler
unsubscribedHandler broker.UnsubscribedHandler
}
// Pattern returns the subscription pattern used to create the subscriber.
func (s *_Subscriber) Pattern() string {
return strings.TrimPrefix(s.natsSub.Subject, s.broker.options.TopicPrefix)
}
// Queue subscribers with the same queue name will create a shared subscription where each receives a subset of messages.
func (s *_Subscriber) Queue() string {
return strings.TrimPrefix(s.natsSub.Queue, s.broker.options.QueuePrefix)
}
// Unsubscribe unsubscribes the subscriber from the topic.
func (s *_Subscriber) Unsubscribe() <-chan struct{} {
s.cancel()
return s.stoppedChan
}
// Next is a blocking call that waits for the next event to be received from the subscriber.
func (s *_Subscriber) Next() (broker.IEvent, error) {
for event := range s.eventChan {
return event, nil
}
return nil, broker.ErrUnsubscribed
}
// EventChan returns a channel that can be used to receive events from the subscriber.
func (s *_Subscriber) EventChan() (<-chan broker.IEvent, error) {
return s.eventChan, nil
}
func (s *_Subscriber) mainLoop() {
defer func() {
s.cancel()
s.broker.wg.Done()
close(s.stoppedChan)
}()
select {
case <-s.Done():
case <-s.broker.ctx.Done():
}
if err := s.natsSub.Unsubscribe(); err != nil {
log.Errorf(s.broker.servCtx, "unsubscribe topic pattern %q with %q failed, %s", s.Pattern(), s.Queue(), err)
} else {
log.Debugf(s.broker.servCtx, "unsubscribe topic pattern %q with %q success", s.Pattern(), s.Queue())
}
if s.eventChan != nil {
close(s.eventChan)
}
s.unsubscribedHandler.Invoke(func(panicErr error) bool {
log.Errorf(s.broker.servCtx, "handle unsubscribed topic pattern %q queue %q failed, %s", s.Pattern(), s.Queue(), panicErr)
return false
}, s)
}
func (s *_Subscriber) handleEventChan(msg *nats.Msg) {
e := &_Event{
msg: msg,
ns: s,
}
select {
case s.eventChan <- e:
default:
var nakErr error
if e.Queue() != "" {
nakErr = e.Nak(context.Background())
}
log.Errorf(s.broker.servCtx, "handle msg from topic %q queue %q failed, receive event chan is full, nak: %v", e.Topic(), e.Queue(), nakErr)
}
}
func (s *_Subscriber) handleEventProcess(msg *nats.Msg) {
e := &_Event{
msg: msg,
ns: s,
}
s.eventHandler.Invoke(func(err error, panicErr error) bool {
if err := generic.FuncError(err, panicErr); err != nil {
log.Errorf(s.broker.servCtx, "handle msg from topic %q queue %q failed, %s", e.Topic(), e.Queue(), err)
}
return panicErr != nil
}, e)
}