e4fee05c96
Update the GO tutorials with PublishWithContext instead of Publish Publish is deprecated. As context, I used: `context.WithTimeout(context.Background(), 5*time.Second)` update the Golang Version to 1.7 Signed-off-by: Gabriele Santomaggio G.santomaggio@gmail.com
115 lines
2.2 KiB
Go
115 lines
2.2 KiB
Go
package main
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import (
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"context"
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"log"
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"math/rand"
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"os"
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"strconv"
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"strings"
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"time"
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amqp "github.com/rabbitmq/amqp091-go"
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)
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func failOnError(err error, msg string) {
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if err != nil {
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log.Panicf("%s: %s", msg, err)
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}
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}
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func randomString(l int) string {
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bytes := make([]byte, l)
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for i := 0; i < l; i++ {
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bytes[i] = byte(randInt(65, 90))
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}
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return string(bytes)
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}
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func randInt(min int, max int) int {
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return min + rand.Intn(max-min)
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}
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func fibonacciRPC(n int) (res int, err error) {
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conn, err := amqp.Dial("amqp://guest:guest@localhost:5672/")
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failOnError(err, "Failed to connect to RabbitMQ")
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defer conn.Close()
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ch, err := conn.Channel()
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failOnError(err, "Failed to open a channel")
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defer ch.Close()
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q, err := ch.QueueDeclare(
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"", // name
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false, // durable
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false, // delete when unused
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true, // exclusive
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false, // noWait
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nil, // arguments
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)
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failOnError(err, "Failed to declare a queue")
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msgs, err := ch.Consume(
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q.Name, // queue
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"", // consumer
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true, // auto-ack
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false, // exclusive
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false, // no-local
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false, // no-wait
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nil, // args
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)
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failOnError(err, "Failed to register a consumer")
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corrId := randomString(32)
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ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
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defer cancel()
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err = ch.PublishWithContext(ctx,
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"", // exchange
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"rpc_queue", // routing key
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false, // mandatory
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false, // immediate
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amqp.Publishing{
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ContentType: "text/plain",
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CorrelationId: corrId,
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ReplyTo: q.Name,
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Body: []byte(strconv.Itoa(n)),
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})
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failOnError(err, "Failed to publish a message")
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for d := range msgs {
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if corrId == d.CorrelationId {
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res, err = strconv.Atoi(string(d.Body))
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failOnError(err, "Failed to convert body to integer")
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break
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}
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}
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return
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}
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func main() {
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rand.Seed(time.Now().UTC().UnixNano())
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n := bodyFrom(os.Args)
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log.Printf(" [x] Requesting fib(%d)", n)
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res, err := fibonacciRPC(n)
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failOnError(err, "Failed to handle RPC request")
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log.Printf(" [.] Got %d", res)
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}
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func bodyFrom(args []string) int {
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var s string
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if (len(args) < 2) || os.Args[1] == "" {
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s = "30"
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} else {
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s = strings.Join(args[1:], " ")
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}
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n, err := strconv.Atoi(s)
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failOnError(err, "Failed to convert arg to integer")
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return n
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}
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