WebSocketServer/modules/rabbitmq/helper.go

package rabbitmq

import (
	"context"
	"encoding/json"

	"clickandjoin.app/websocketserver/modules/structs"
	"clickandjoin.app/websocketserver/modules/utils"
	"clickandjoin.app/websocketserver/socketclients"
	gorabbitmqclient "git.clickandjoin.umbach.dev/ClickandJoin/go-rabbitmq-client"
	"github.com/google/uuid"
	amqp "github.com/rabbitmq/amqp091-go"
	"github.com/sirupsen/logrus"
)

func PublishClientMessage(rabbitMqMessage structs.RabbitMqMessage) error {
	msg, err := json.Marshal(rabbitMqMessage)

	if err != nil {
		logrus.Errorln("Failed to marshal rabbitMqMessage, err:", err)
		return err
	}

	err = WebsocketClient.PushExchangeMessage(rabbitMqMessage.Rec, msg)

	if err != nil {
		logrus.Errorln("Failed to publish client msg, err:", err)
		return err
	}

	return nil
}

// For each user a queue is created in the websocket exchange channel where he receives his messages
func CreateWSClientBinding(socketClient *structs.SocketClient, id string) (err error) {
	msgs, err := createWSClientQueueAndBindingConsumer(socketClient, id)

	if err != nil {
		logrus.Errorln("Failed to create ws client queue and binding consumer, err:", err)
		return err
	}

	// canceled when websocket client disconnects
	ctx, cancel := context.WithCancel(context.Background())

	socketClient.CancelFunc = cancel

	go func() {
		for {
			select {
			case <-ctx.Done():
				logrus.Println("DONE!")
				return
			case <-WebSocketChannelClosedChannel:
				// This case handles the event of closed channel e.g. abnormal shutdown
				msgs, err = createWSClientQueueAndBindingConsumer(socketClient, id)

				if err != nil {
					// If the AMQP channel is not ready, it will continue the loop. Next
					// iteration will enter this case because chClosedCh is closed by the
					// library
					continue
				}

				logrus.Debugln("Re-set ws client channel", socketClient.RabbitMqConsumerId)

				// Re-set channel to receive notifications
				// The library closes this channel after abnormal shutdown
				WebSocketChannelClosedChannel = make(chan *amqp.Error, 1)
				WebsocketClient.Channel.NotifyClose(WebSocketChannelClosedChannel)

			case msg := <-msgs:
				var receivedMessage structs.ReceivedMessage

				err = utils.UnmarshalReceivedMessage(msg.Body, &receivedMessage)

				if err != nil {
					logrus.Errorln("Failed to unmarshal received msg, err:", err)
				}

				logrus.Debugln("RABBITMQ RECEIVED MESSAGE:", receivedMessage)

				err = socketClient.SendMessage(structs.SendSocketMessage{Cmd: receivedMessage.Cmd, Body: receivedMessage.Body})

				if err != nil {
					logrus.Errorln("Failed to send message to client, err:", err)
				}
			}
		}
	}()

	return nil
}

func createWSClientQueueAndBindingConsumer(socketClient *structs.SocketClient, id string) (msgs <-chan amqp.Delivery, err error) {
	q, err := WebsocketClient.QueueDeclare(gorabbitmqclient.QueueDeclareSettings{
		Name:             "",
		Durable:          false,
		DeleteWhenUnused: false,
		Exclusive:        true,
		NoWait:           false,
		Arguments:        nil,
	})

	if err != nil {
		return msgs, err
	}

	// set an ID for the consumer to delete the consumer after the socket user has disconnected
	socketClient.RabbitMqConsumerId = uuid.New().String()

	// store queue name in the client to delete it when the client disconnects from the websocket
	socketClient.RabbitMqQueueName = q.Name

	err = WebsocketClient.QueueBind(gorabbitmqclient.QueueBindSettings{
		QueueName:  q.Name,
		RoutingKey: id,
		Exchange:   exchangeWebsocketMessages,
		NoWait:     false,
		Arguments:  nil,
	})

	if err != nil {
		logrus.Errorln("Failed to bind queue, err:", err)
		return msgs, err
	}

	return WebsocketClient.ConsumeChannelMessages(gorabbitmqclient.ChannelConsumeSettings{
		QueueName: q.Name,
		Consumer:  socketClient.RabbitMqConsumerId,
		AutoAck:   true,
		Exclusive: false,
		NoLocal:   false,
		NoWait:    false,
		Arguments: nil,
	})
}

func DeleteWSClient(consumerId string, qName string) error {
	// delete consumer
	err := WebsocketClient.Channel.Cancel(consumerId, false)

	if err != nil {
		logrus.Errorln("Failed to delete consumer, err:", err)
		return err
	}

	// delete queue and queue binding
	_, err = WebsocketClient.Channel.QueueDelete(qName, false, true, false)

	if err != nil {
		logrus.Errorln("Failed to delete queue, err:", err)
		return err
	}

	logrus.Println("deleted", consumerId, qName)

	return nil
}

func ApiBroadcastMessagesHandling() {
	msgs, err := apiBroadcastMessagesConsumer()

	if err != nil {
		logrus.Errorln("Failed to create api broadcast message consumer, err:", err)
		return
	}

	channelClosedChannel := make(chan *amqp.Error, 1)
	ApiBroadcastClient.Channel.NotifyClose(channelClosedChannel)

	go func() {
		for {
			select {
			case <-channelClosedChannel:
				// This case handles the event of closed channel e.g. abnormal shutdown
				msgs, err = apiBroadcastMessagesConsumer()

				if err != nil {
					// If the AMQP channel is not ready, it will continue the loop. Next
					// iteration will enter this case because chClosedCh is closed by the
					// library
					continue
				}

				logrus.Debugln("Re-set api broadcast channel")

				// Re-set channel to receive notifications
				// The library closes this channel after abnormal shutdown
				channelClosedChannel = make(chan *amqp.Error, 1)
				ApiBroadcastClient.Channel.NotifyClose(channelClosedChannel)

			case msg := <-msgs:
				var receivedMessage structs.ReceivedMessage

				err = utils.UnmarshalReceivedMessage(msg.Body, &receivedMessage)

				if err != nil {
					logrus.Errorln("Failed to unmarshal received msg, err:", err)
				}

				logrus.Debugln("RABBITMQ RECEIVED BROADCAST MESSAGE:", receivedMessage)

				socketclients.BroadcastMessage(structs.SendSocketMessage{Cmd: receivedMessage.Cmd, Body: receivedMessage.Body})
			}
		}
	}()
}

func apiBroadcastMessagesConsumer() (msgs <-chan amqp.Delivery, err error) {
	return ApiBroadcastClient.ConsumeChannelMessages(gorabbitmqclient.ChannelConsumeSettings{
		QueueName: ApiBroadcastClient.AssignedQueueName,
		Consumer:  "",
		AutoAck:   true,
		Exclusive: false,
		NoLocal:   false,
		NoWait:    false,
		Arguments: nil,
	})
}