/
nats.go
119 lines (106 loc) · 3.05 KB
/
nats.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
// Copyright 2019 kemar
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package event
import (
"bytes"
"encoding/gob"
"time"
"github.com/nats-io/go-nats"
"github.com/hackerrithm/blackfox/services/backend/reaction/pkg/domain"
)
// NatsEventStore ...
type NatsEventStore struct {
nc *nats.Conn
reactionCreatedSubscription *nats.Subscription
reactionCreatedChan chan ReactionCreatedMessage
}
// NewNats ...
func NewNats(url string) (*NatsEventStore, error) {
nc, err := nats.Connect(url)
if err != nil {
return nil, err
}
return &NatsEventStore{nc: nc}, nil
}
// SubscribeReactionCreated ...
func (e *NatsEventStore) SubscribeReactionCreated() (<-chan ReactionCreatedMessage, error) {
m := ReactionCreatedMessage{}
e.reactionCreatedChan = make(chan ReactionCreatedMessage, 64)
ch := make(chan *nats.Msg, 64)
var err error
e.reactionCreatedSubscription, err = e.nc.ChanSubscribe(m.Key(), ch)
if err != nil {
return nil, err
}
// Decode message
go func() {
for {
select {
case msg := <-ch:
e.readMessage(msg.Data, &m)
e.reactionCreatedChan <- m
}
}
}()
return (<-chan ReactionCreatedMessage)(e.reactionCreatedChan), nil
}
// OnReactionCreated ...
func (e *NatsEventStore) OnReactionCreated(f func(ReactionCreatedMessage)) (err error) {
m := ReactionCreatedMessage{}
e.reactionCreatedSubscription, err = e.nc.Subscribe(m.Key(), func(msg *nats.Msg) {
e.readMessage(msg.Data, &m)
f(m)
})
return
}
// Close ...
func (e *NatsEventStore) Close() {
if e.nc != nil {
e.nc.Close()
}
if e.reactionCreatedSubscription != nil {
e.reactionCreatedSubscription.Unsubscribe()
}
close(e.reactionCreatedChan)
}
const (
layoutISO = "2006-01-02"
layoutUS = "January 2, 2006"
)
// PublishReactionCreated ...
func (e *NatsEventStore) PublishReactionCreated(reaction domain.Reaction) error {
formatedTime := reaction.Date.Format(time.RFC1123)
x, _ := time.Parse(layoutISO, formatedTime)
m := ReactionCreatedMessage{reaction.ID.Hex(), reaction.PersonID.Hex(), reaction.Description, reaction.Type, reaction.Details, x}
data, err := e.writeMessage(&m)
if err != nil {
return err
}
return e.nc.Publish(m.Key(), data)
}
// writeMessage ...maybe changed back to mq
func (e *NatsEventStore) writeMessage(m Message) ([]byte, error) {
b := bytes.Buffer{}
err := gob.NewEncoder(&b).Encode(m)
if err != nil {
return nil, err
}
return b.Bytes(), nil
}
// readMessage ...
func (e *NatsEventStore) readMessage(data []byte, m interface{}) error {
b := bytes.Buffer{}
b.Write(data)
return gob.NewDecoder(&b).Decode(m)
}