Broadcast to tmq queues example (#43)

* broadcast example
---------
Signed-off-by: Gabriele Santomaggio <G.santomaggio@gmail.com>

docs/examples/README.md

@@ -8,4 +8,5 @@
 - [Publisher per message target](publisher_msg_targets) - An example of how to use a single publisher to send messages in different queues with the address to the message target in the message properties.
 - [Video](video) - From the YouTube tutorial [AMQP 1.0 with Golang](https://youtu.be/iR1JUFh3udI)
 - [TLS](tls) - An example of how to use TLS with the AMQP 1.0 client.
-- [Advanced Settings](advanced_settings) - An example of how to use the advanced connection settings of the AMQP 1.0 client.
+- [Advanced Settings](advanced_settings) - An example of how to use the advanced connection settings of the AMQP 1.0 client.
+- [Broadcast](broadcast) - An example of how to use fanout to broadcast messages to multiple auto-deleted queues.

docs/examples/broadcast/broadcast.go

@@ -0,0 +1,110 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	rmq "github.com/rabbitmq/rabbitmq-amqp-go-client/pkg/rabbitmqamqp"
+	"time"
+)
+
+func main() {
+
+	env := rmq.NewEnvironment("amqp://guest:guest@localhost:5672/", nil)
+
+	// Open a connection to the AMQP 1.0 server ( RabbitMQ >= 4.0)
+	amqpConnection, err := env.NewConnection(context.Background())
+
+	if err != nil {
+		rmq.Error("Error opening connection", err)
+		return
+	}
+	const broadcastExchange = "broadcast"
+	// Create the management interface for the connection
+	// so we can declare exchanges, queues, and bindings
+	management := amqpConnection.Management()
+	_, err = management.DeclareExchange(context.Background(), &rmq.FanOutExchangeSpecification{
+		Name: broadcastExchange,
+	})
+
+	if err != nil {
+		rmq.Error("Error declaring exchange", err)
+		return
+	}
+
+	for i := 0; i < 5; i++ {
+		// create temp queues
+		q, err := management.DeclareQueue(context.Background(), &rmq.AutoGeneratedQueueSpecification{
+			IsAutoDelete: true,
+			IsExclusive:  true,
+		})
+
+		if err != nil {
+			rmq.Error("Error DeclareQueue", err)
+			return
+		}
+
+		_, err = management.Bind(context.TODO(), &rmq.ExchangeToQueueBindingSpecification{
+			SourceExchange:   broadcastExchange,
+			DestinationQueue: q.Name(),
+		})
+
+		if err != nil {
+			rmq.Error("Error binding", err)
+			return
+		}
+
+		go func(idx int) {
+			consumer, err := amqpConnection.NewConsumer(context.Background(), q.Name(), nil)
+			if err != nil {
+				rmq.Error("Error creating consumer", err)
+				return
+			}
+			for {
+				dcx, err1 := consumer.Receive(context.Background())
+				if err1 != nil {
+					rmq.Error("Error receiving message", err)
+					return
+				}
+				rmq.Info("[Consumer]", "index", idx, "msg", fmt.Sprintf("%s", dcx.Message().Data), "[queue]", q.Name())
+				err1 = dcx.Accept(context.Background())
+				if err1 != nil {
+					rmq.Error("Error accepting message", err)
+					return
+				}
+			}
+		}(i)
+	}
+
+	publisher, err := amqpConnection.NewPublisher(context.Background(), &rmq.ExchangeAddress{
+		Exchange: broadcastExchange,
+	}, nil)
+
+	if err != nil {
+		rmq.Error("Error creating publisher", err)
+		return
+	}
+
+	for i := 0; i < 10_000; i++ {
+		publishResult, err := publisher.Publish(context.Background(),
+			rmq.NewMessage([]byte("Hello AMQP 1.0 - id:"+fmt.Sprintf("%d", i))))
+		if err != nil {
+			rmq.Error("Error publishing message", err)
+			return
+		}
+
+		switch publishResult.Outcome.(type) {
+		// publish result
+		case *rmq.StateAccepted:
+			rmq.Info("[Publisher] Message accepted", "message", publishResult.Message.GetData())
+		default:
+			rmq.Error("[Publisher] Message not accepted", "outcome", publishResult.Outcome)
+		}
+		time.Sleep(1 * time.Second)
+	}
+
+	// press any key to close the connection
+
+	var input string
+	_, _ = fmt.Scanln(&input)
+
+}