-
Notifications
You must be signed in to change notification settings - Fork 0
/
main.go
227 lines (189 loc) · 5.11 KB
/
main.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
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
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
package main
import (
"encoding/json"
"fmt"
"log"
"math/rand"
"os"
"strconv"
"time"
ot "github.com/opentracing/opentracing-go"
"github.com/opentracing/opentracing-go/ext"
otlog "github.com/opentracing/opentracing-go/log"
"github.com/streadway/amqp"
)
const (
Service = "dispatch"
)
var (
amqpUri string
rabbitChan *amqp.Channel
rabbitCloseError chan *amqp.Error
rabbitReady chan bool
errorPercent int
dataCenters = []string{
"asia-northeast2",
"asia-south1",
"europe-west3",
"us-east1",
"us-west1",
}
)
func connectToRabbitMQ(uri string) *amqp.Connection {
for {
conn, err := amqp.Dial(uri)
if err == nil {
return conn
}
log.Println(err)
log.Printf("Reconnecting to %s\n", uri)
time.Sleep(1 * time.Second)
}
}
func rabbitConnector(uri string) {
var rabbitErr *amqp.Error
for {
rabbitErr = <-rabbitCloseError
if rabbitErr == nil {
return
}
log.Printf("Connecting to %s\n", amqpUri)
rabbitConn := connectToRabbitMQ(uri)
rabbitConn.NotifyClose(rabbitCloseError)
var err error
// create mappings here
rabbitChan, err = rabbitConn.Channel()
failOnError(err, "Failed to create channel")
// create exchange
err = rabbitChan.ExchangeDeclare("robot-shop", "direct", true, false, false, false, nil)
failOnError(err, "Failed to create exchange")
// create queue
queue, err := rabbitChan.QueueDeclare("orders", true, false, false, false, nil)
failOnError(err, "Failed to create queue")
// bind queue to exchange
err = rabbitChan.QueueBind(queue.Name, "orders", "robot-shop", false, nil)
failOnError(err, "Failed to bind queue")
// signal ready
rabbitReady <- true
}
}
func failOnError(err error, msg string) {
if err != nil {
log.Fatalf("%s : %s", msg, err)
}
}
func getOrderId(order []byte) string {
id := "unknown"
var f interface{}
err := json.Unmarshal(order, &f)
if err == nil {
m := f.(map[string]interface{})
id = m["orderid"].(string)
}
return id
}
func createSpan(headers map[string]interface{}, order string) {
// headers is map[string]interface{}
// carrier is map[string]string
carrier := make(ot.TextMapCarrier)
// convert by copying k, v
for k, v := range headers {
carrier[k] = v.(string)
}
// get the order id
log.Printf("order %s\n", order)
// opentracing
var span ot.Span
tracer := ot.GlobalTracer()
spanContext, err := tracer.Extract(ot.HTTPHeaders, carrier)
if err == nil {
log.Println("Creating child span")
// create child span
span = tracer.StartSpan("getOrder", ot.ChildOf(spanContext))
fakeDataCenter := dataCenters[rand.Intn(len(dataCenters))]
span.SetTag("datacenter", fakeDataCenter)
} else {
log.Println(err)
log.Println("Failed to get context from headers")
log.Println("Creating root span")
// create root span
span = tracer.StartSpan("getOrder")
}
span.SetTag(string(ext.SpanKind), ext.SpanKindConsumerEnum)
span.SetTag(string(ext.MessageBusDestination), "robot-shop")
span.SetTag("exchange", "robot-shop")
span.SetTag("sort", "consume")
span.SetTag("address", "rabbitmq")
span.SetTag("key", "orders")
span.LogFields(otlog.String("orderid", order))
defer span.Finish()
time.Sleep(time.Duration(42+rand.Int63n(42)) * time.Millisecond)
if rand.Intn(100) < errorPercent {
span.SetTag("error", true)
span.LogFields(
otlog.String("error.kind", "Exception"),
otlog.String("message", "Failed to dispatch to SOP"))
log.Println("Span tagged with error")
}
processSale(span)
}
func processSale(parentSpan ot.Span) {
tracer := ot.GlobalTracer()
span := tracer.StartSpan("processSale", ot.ChildOf(parentSpan.Context()))
defer span.Finish()
span.SetTag(string(ext.SpanKind), "intermediate")
span.LogFields(otlog.String("info", "Order sent for processing"))
time.Sleep(time.Duration(42+rand.Int63n(42)) * time.Millisecond)
}
func main() {
rand.Seed(time.Now().Unix())
// Init amqpUri
// get host from environment
amqpHost, ok := os.LookupEnv("AMQP_HOST")
amqpUser, ok := os.LookupEnv("AMQP_USER")
amqpPass, ok := os.LookupEnv("AMQP_PASS")
if !ok {
amqpHost = "rabbitmq"
}
amqpUri = fmt.Sprintf("amqp://%s:%s@%s:5672/", amqpUser, amqpPass, amqpHost)
// get error threshold from environment
errorPercent = 0
epct, ok := os.LookupEnv("DISPATCH_ERROR_PERCENT")
if ok {
epcti, err := strconv.Atoi(epct)
if err == nil {
if epcti > 100 {
epcti = 100
}
if epcti < 0 {
epcti = 0
}
errorPercent = epcti
}
}
log.Printf("Error Percent is %d\n", errorPercent)
// MQ error channel
rabbitCloseError = make(chan *amqp.Error)
// MQ ready channel
rabbitReady = make(chan bool)
go rabbitConnector(amqpUri)
rabbitCloseError <- amqp.ErrClosed
go func() {
for {
// wait for rabbit to be ready
ready := <-rabbitReady
log.Printf("Rabbit MQ ready %v\n", ready)
// subscribe to bound queue
msgs, err := rabbitChan.Consume("orders", "", true, false, false, false, nil)
failOnError(err, "Failed to consume")
for d := range msgs {
log.Printf("Order %s\n", d.Body)
log.Printf("Headers %v\n", d.Headers)
id := getOrderId(d.Body)
go createSpan(d.Headers, id)
}
}
}()
log.Println("Waiting for messages")
select {}
}