Golang amqp.Dial函数代码示例

func ExampleConnection_NotifyBlocked() {
	// Simply logs when the server throttles the TCP connection for publishers

	// Test this by tuning your server to have a low memory watermark:
	// rabbitmqctl set_vm_memory_high_watermark 0.00000001

	conn, err := amqp.Dial("amqp://guest:[email protected]:5672/")
	if err != nil {
		log.Fatalf("connection.open: %s", err)
	}
	defer conn.Close()

	blockings := conn.NotifyBlocked(make(chan amqp.Blocking))
	go func() {
		for b := range blockings {
			if b.Active {
				log.Printf("TCP blocked: %q", b.Reason)
			} else {
				log.Printf("TCP unblocked")
			}
		}
	}()

	// Your application domain channel setup publishings
	publishAllTheThings(conn)
}

// AmqpChannel is the same as amqpConnect in boulder, but with even
// more aggressive error dropping
func AmqpChannel(url string) (ch *amqp.Channel) {
	conn, err := amqp.Dial(url)
	FailOnError(err, "Unable to connect to AMQP server")

	ch, err = conn.Channel()
	FailOnError(err, "Unable to establish channel to AMQP server")
	return
}

// A simplified way to get a channel for a given AMQP server
func amqpConnect(url string) (ch *amqp.Channel, err error) {
	conn, err := amqp.Dial(url)
	if err != nil {
		return
	}

	ch, err = conn.Channel()
	return
}

// Every connection should declare the topology they expect
func setup(url, queue string) (*amqp.Connection, *amqp.Channel, error) {
	conn, err := amqp.Dial(url)
	if err != nil {
		return nil, nil, err
	}

	ch, err := conn.Channel()
	if err != nil {
		return nil, nil, err
	}

	if _, err := ch.QueueDeclare(queue, false, true, false, false, nil); err != nil {
		return nil, nil, err
	}

	return conn, ch, nil
}

func ExampleChannel_Publish() {
	// Connects opens an AMQP connection from the credentials in the URL.
	conn, err := amqp.Dial("amqp://guest:[email protected]:5672/")
	if err != nil {
		log.Fatalf("connection.open: %s", err)
	}

	// This waits for a server acknowledgment which means the sockets will have
	// flushed all outbound publishings prior to returning.  It's important to
	// block on Close to not lose any publishings.
	defer conn.Close()

	c, err := conn.Channel()
	if err != nil {
		log.Fatalf("channel.open: %s", err)
	}

	// We declare our topology on both the publisher and consumer to ensure they
	// are the same.  This is part of AMQP being a programmable messaging model.
	//
	// See the Channel.Consume example for the complimentary declare.
	err = c.ExchangeDeclare("logs", "topic", true, false, false, false, nil)
	if err != nil {
		log.Fatalf("exchange.declare: %v", err)
	}

	// Prepare this message to be persistent.  Your publishing requirements may
	// be different.
	msg := amqp.Publishing{
		DeliveryMode: amqp.Persistent,
		Timestamp:    time.Now(),
		ContentType:  "text/plain",
		Body:         []byte("Go Go AMQP!"),
	}

	// This is not a mandatory delivery, so it will be dropped if there are no
	// queues bound to the logs exchange.
	err = c.Publish("logs", "info", false, false, msg)
	if err != nil {
		// Since publish is asynchronous this can happen if the network connection
		// is reset or if the server has run out of resources.
		log.Fatalf("basic.publish: %v", err)
	}
}

func main() {
	server := *server
	conn, err := amqp.Dial(server)
	cmd.FailOnError(err, "Could not connect to AMQP")
	ch, err := conn.Channel()
	cmd.FailOnError(err, "Could not connect to AMQP")

	err = ch.ExchangeDeclare(
		amqpExchange,
		amqpExchangeType,
		amqpExchangeDurable,
		amqpDeleteUnused,
		amqpInternal,
		amqpNoWait,
		nil)
	cmd.FailOnError(err, "Declaring exchange")

	_, err = ch.QueueDeclare(
		monitorQueueName,
		amqpQueueDurable,
		amqpDeleteUnused,
		amqpExclusive,
		amqpNoWait,
		nil)
	if err != nil {
		cmd.FailOnError(err, "Could not declare queue")
	}

	routingKey := "#" //wildcard

	err = ch.QueueBind(
		monitorQueueName,
		routingKey,
		amqpExchange,
		false,
		nil)
	if err != nil {
		txt := fmt.Sprintf("Could not bind to queue [%s]. NOTE: You may need to delete %s to re-trigger the bind attempt after fixing permissions, or manually bind the queue to %s.", monitorQueueName, monitorQueueName, routingKey)
		cmd.FailOnError(err, txt)
	}
}

// AmqpChannel sets a AMQP connection up using SSL if configuration is provided
func AmqpChannel(conf cmd.Config) (*amqp.Channel, error) {
	var conn *amqp.Connection
	var err error

	log := blog.GetAuditLogger()

	if conf.AMQP.Insecure == true {
		// If the Insecure flag is true, then just go ahead and connect
		conn, err = amqp.Dial(conf.AMQP.Server)
	} else {
		// The insecure flag is false or not set, so we need to load up the options
		log.Info("AMQPS: Loading TLS Options.")

		if strings.HasPrefix(conf.AMQP.Server, "amqps") == false {
			err = fmt.Errorf("AMQPS: Not using an AMQPS URL. To use AMQP instead of AMQPS, set insecure=true.")
			return nil, err
		}

		if conf.AMQP.TLS == nil {
			err = fmt.Errorf("AMQPS: No TLS configuration provided. To use AMQP instead of AMQPS, set insecure=true.")
			return nil, err
		}

		cfg := new(tls.Config)

		// If the configuration specified a certificate (or key), load them
		if conf.AMQP.TLS.CertFile != nil || conf.AMQP.TLS.KeyFile != nil {
			// But they have to give both.
			if conf.AMQP.TLS.CertFile == nil || conf.AMQP.TLS.KeyFile == nil {
				err = fmt.Errorf("AMQPS: You must set both of the configuration values AMQP.TLS.KeyFile and AMQP.TLS.CertFile")
				return nil, err
			}

			cert, err := tls.LoadX509KeyPair(*conf.AMQP.TLS.CertFile, *conf.AMQP.TLS.KeyFile)
			if err != nil {
				err = fmt.Errorf("AMQPS: Could not load Client Certificate or Key: %s", err)
				return nil, err
			}

			log.Info("AMQPS: Configured client certificate for AMQPS.")
			cfg.Certificates = append(cfg.Certificates, cert)
		}

		// If the configuration specified a CA certificate, make it the only
		// available root.
		if conf.AMQP.TLS.CACertFile != nil {
			cfg.RootCAs = x509.NewCertPool()

			ca, err := ioutil.ReadFile(*conf.AMQP.TLS.CACertFile)
			if err != nil {
				err = fmt.Errorf("AMQPS: Could not load CA Certificate: %s", err)
				return nil, err
			}
			cfg.RootCAs.AppendCertsFromPEM(ca)
			log.Info("AMQPS: Configured CA certificate for AMQPS.")
		}

		conn, err = amqp.DialTLS(conf.AMQP.Server, cfg)
	}

	if err != nil {
		return nil, err
	}

	err = AMQPDeclareExchange(conn)
	if err != nil {
		return nil, err
	}

	return conn.Channel()
}

// AmqpChannel sets a AMQP connection up using SSL if configuration is provided
func AmqpChannel(conf cmd.Config) (*amqp.Channel, error) {
	var conn *amqp.Connection
	var err error

	log := blog.GetAuditLogger()

	if conf.AMQP.TLS == nil {
		// Configuration did not specify TLS options, but Dial will
		// use TLS anyway if the URL scheme is "amqps"
		conn, err = amqp.Dial(conf.AMQP.Server)
	} else {
		// They provided TLS options, so let's load them.
		log.Info("AMQPS: Loading TLS Options.")

		if strings.HasPrefix(conf.AMQP.Server, "amqps") == false {
			err = fmt.Errorf("AMQPS: TLS configuration provided, but not using an AMQPS URL")
			return nil, err
		}

		cfg := new(tls.Config)

		// If the configuration specified a certificate (or key), load them
		if conf.AMQP.TLS.CertFile != nil || conf.AMQP.TLS.KeyFile != nil {
			// But they have to give both.
			if conf.AMQP.TLS.CertFile == nil || conf.AMQP.TLS.KeyFile == nil {
				err = fmt.Errorf("AMQPS: You must set both of the configuration values AMQP.TLS.KeyFile and AMQP.TLS.CertFile")
				return nil, err
			}

			cert, err := tls.LoadX509KeyPair(*conf.AMQP.TLS.CertFile, *conf.AMQP.TLS.KeyFile)
			if err != nil {
				err = fmt.Errorf("AMQPS: Could not load Client Certificate or Key: %s", err)
				return nil, err
			}

			log.Info("AMQPS: Configured client certificate for AMQPS.")
			cfg.Certificates = append(cfg.Certificates, cert)
		}

		// If the configuration specified a CA certificate, make it the only
		// available root.
		if conf.AMQP.TLS.CACertFile != nil {
			cfg.RootCAs = x509.NewCertPool()

			ca, err := ioutil.ReadFile(*conf.AMQP.TLS.CACertFile)
			if err != nil {
				err = fmt.Errorf("AMQPS: Could not load CA Certificate: %s", err)
				return nil, err
			}
			cfg.RootCAs.AppendCertsFromPEM(ca)
			log.Info("AMQPS: Configured CA certificate for AMQPS.")
		}

		conn, err = amqp.DialTLS(conf.AMQP.Server, cfg)
	}

	if err != nil {
		return nil, err
	}

	err = AMQPDeclareExchange(conn)
	if err != nil {
		return nil, err
	}

	return conn.Channel()
}

func ExampleChannel_Confirm_bridge() {
	// This example acts as a bridge, shoveling all messages sent from the source
	// exchange "log" to destination exchange "log".

	// Confirming publishes can help from overproduction and ensure every message
	// is delivered.

	// Setup the source of the store and forward
	source, err := amqp.Dial("amqp://source/")
	if err != nil {
		log.Fatalf("connection.open source: %s", err)
	}
	defer source.Close()

	chs, err := source.Channel()
	if err != nil {
		log.Fatalf("channel.open source: %s", err)
	}

	if err := chs.ExchangeDeclare("log", "topic", true, false, false, false, nil); err != nil {
		log.Fatalf("exchange.declare destination: %s", err)
	}

	if _, err := chs.QueueDeclare("remote-tee", true, true, false, false, nil); err != nil {
		log.Fatalf("queue.declare source: %s", err)
	}

	if err := chs.QueueBind("remote-tee", "#", "logs", false, nil); err != nil {
		log.Fatalf("queue.bind source: %s", err)
	}

	shovel, err := chs.Consume("remote-tee", "shovel", false, false, false, false, nil)
	if err != nil {
		log.Fatalf("basic.consume source: %s", err)
	}

	// Setup the destination of the store and forward
	destination, err := amqp.Dial("amqp://destination/")
	if err != nil {
		log.Fatalf("connection.open destination: %s", err)
	}
	defer destination.Close()

	chd, err := destination.Channel()
	if err != nil {
		log.Fatalf("channel.open destination: %s", err)
	}

	if err := chd.ExchangeDeclare("log", "topic", true, false, false, false, nil); err != nil {
		log.Fatalf("exchange.declare destination: %s", err)
	}

	// Buffer of 1 for our single outstanding publishing
	pubAcks, pubNacks := chd.NotifyConfirm(make(chan uint64, 1), make(chan uint64, 1))

	if err := chd.Confirm(false); err != nil {
		log.Fatalf("confirm.select destination: %s", err)
	}

	// Now pump the messages, one by one, a smarter implementation
	// would batch the deliveries and use multiple ack/nacks
	for {
		msg, ok := <-shovel
		if !ok {
			log.Fatalf("source channel closed, see the reconnect example for handling this")
		}

		err = chd.Publish("logs", msg.RoutingKey, false, false, amqp.Publishing{
			// Copy all the properties
			ContentType:     msg.ContentType,
			ContentEncoding: msg.ContentEncoding,
			DeliveryMode:    msg.DeliveryMode,
			Priority:        msg.Priority,
			CorrelationId:   msg.CorrelationId,
			ReplyTo:         msg.ReplyTo,
			Expiration:      msg.Expiration,
			MessageId:       msg.MessageId,
			Timestamp:       msg.Timestamp,
			Type:            msg.Type,
			UserId:          msg.UserId,
			AppId:           msg.AppId,

			// Custom headers
			Headers: msg.Headers,

			// And the body
			Body: msg.Body,
		})

		if err != nil {
			msg.Nack(false, false)
			log.Fatalf("basic.publish destination: %s", msg)
		}

		// only ack the source delivery when the destination acks the publishing
		// here you could check for delivery order by keeping a local state of
		// expected delivery tags
		select {
		case <-pubAcks:
			msg.Ack(false)
//.........这里部分代码省略.........

func ExampleChannel_Consume() {
	// Connects opens an AMQP connection from the credentials in the URL.
	conn, err := amqp.Dial("amqp://guest:[email protected]:5672/")
	if err != nil {
		log.Fatalf("connection.open: %s", err)
	}
	defer conn.Close()

	c, err := conn.Channel()
	if err != nil {
		log.Fatalf("channel.open: %s", err)
	}

	// We declare our topology on both the publisher and consumer to ensure they
	// are the same.  This is part of AMQP being a programmable messaging model.
	//
	// See the Channel.Publish example for the complimentary declare.
	err = c.ExchangeDeclare("logs", "topic", true, false, false, false, nil)
	if err != nil {
		log.Fatalf("exchange.declare: %s", err)
	}

	// Establish our queue topologies that we are responsible for
	type bind struct {
		queue string
		key   string
	}

	bindings := []bind{
		bind{"page", "alert"},
		bind{"email", "info"},
		bind{"firehose", "#"},
	}

	for _, b := range bindings {
		_, err = c.QueueDeclare(b.queue, true, false, false, false, nil)
		if err != nil {
			log.Fatalf("queue.declare: %v", err)
		}

		err = c.QueueBind(b.queue, b.key, "logs", false, nil)
		if err != nil {
			log.Fatalf("queue.bind: %v", err)
		}
	}

	// Set our quality of service.  Since we're sharing 3 consumers on the same
	// channel, we want at least 3 messages in flight.
	err = c.Qos(3, 0, false)
	if err != nil {
		log.Fatalf("basic.qos: %v", err)
	}

	// Establish our consumers that have different responsibilities.  Our first
	// two queues do not ack the messages on the server, so require to be acked
	// on the client.

	pages, err := c.Consume("page", "pager", false, false, false, false, nil)
	if err != nil {
		log.Fatalf("basic.consume: %v", err)
	}

	go func() {
		for log := range pages {
			// ... this consumer is responsible for sending pages per log
			log.Ack(false)
		}
	}()

	// Notice how the concern for which messages arrive here are in the AMQP
	// topology and not in the queue.  We let the server pick a consumer tag this
	// time.

	emails, err := c.Consume("email", "", false, false, false, false, nil)
	if err != nil {
		log.Fatalf("basic.consume: %v", err)
	}

	go func() {
		for log := range emails {
			// ... this consumer is responsible for sending emails per log
			log.Ack(false)
		}
	}()

	// This consumer requests that every message is acknowledged as soon as it's
	// delivered.

	firehose, err := c.Consume("firehose", "", true, false, false, false, nil)
	if err != nil {
		log.Fatalf("basic.consume: %v", err)
	}

	// To show how to process the items in parallel, we'll use a work pool.
	for i := 0; i < runtime.NumCPU(); i++ {
		go func(work <-chan amqp.Delivery) {
			for _ = range work {
				// ... this consumer pulls from the firehose and doesn't need to acknowledge
			}
		}(firehose)
//.........这里部分代码省略.........