Go语言学习笔记（八）golang 操作 Redis & Mysql & RabbitMQ
package mainimport (
"fmt"
"log"
"math/rand"
"os"
"strconv"
"strings"
"time"
"github.com/streadway/amqp"
)
/*
RPC模式
请求方
*/
func failOnError(err error, msg string) {
if err != nil {
log.Fatalf("%s: %s", msg, err)
panic(fmt.Sprintf("%s: %s", msg, err))
}
}
func randomString(l int) string {
bytes := make([]byte, l)
for i := 0; i < l; i++ {
bytes = byte(randInt(65, 90))
}
return string(bytes)
}
func randInt(min int, max int) int {
return min + rand.Intn(max-min)
}
func fibonacciRPC(n int) (res int, err error) {
conn, err := amqp.Dial("amqp://guest:guest@localhost:5672/")
failOnError(err, "Failed to connect to RabbitMQ")
defer conn.Close()
ch, err := conn.Channel()
failOnError(err, "Failed to open a channel")
defer ch.Close()
// 队列声明
q, err := ch.QueueDeclare(
"", // name
false, // durable
false, // delete when usused
true,// exclusive 为真即连接断开就删除
false, // noWait
nil, // arguments
)
failOnError(err, "Failed to declare a queue")
msgs, err := ch.Consume(
q.Name, // queue
"", // consumer
true, // auto-ack
false,// exclusive 这个为真，服务器会认为这是该队列唯一的消费者
false,// no-local
false,// no-wait
nil, // args
)
failOnError(err, "Failed to register a consumer")
corrId := randomString(32)
err = ch.Publish(
"", // exchange
"rpc_queue", // routing key
false, // mandatory
false, // immediate
amqp.Publishing{
ContentType: "text/plain",
CorrelationId: corrId,
ReplyTo: q.Name,
Body: []byte(strconv.Itoa(n)),
})
failOnError(err, "Failed to publish a message")
for d := range msgs {
if corrId == d.CorrelationId {
res, err = strconv.Atoi(string(d.Body))
failOnError(err, "Failed to convert body to integer")
break
}
}
return
}
func main() {
rand.Seed(time.Now().UTC().UnixNano())
n := bodyFrom(os.Args)
log.Printf(" Requesting fib(%d)", n)
res, err := fibonacciRPC(n)
failOnError(err, "Failed to handle RPC request")
log.Printf(" [.] Got %d", res)
}
func bodyFrom(args []string) int {
var s string
if (len(args) < 2) || os.Args == "" {
s = "30"
} else {
s = strings.Join(args, " ")
}
n, err := strconv.Atoi(s)
failOnError(err, "Failed to convert arg to integer")
return n
}
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