channel.go

package rabbit

import (
	"context"
	"fmt"
	"sync/atomic"
	"time"

	amqp "github.com/rabbitmq/amqp091-go"

	"github.com/shortlink-org/shortlink/pkg/logger"
)

// Channel amqp.Channel wapper
type Channel struct {
	log logger.Logger
	*amqp.Channel
	delay  int
	closed int32
}

// IsClosed indicate closed by developer
func (ch *Channel) IsClosed() bool {
	return atomic.LoadInt32(&ch.closed) == 1
}

// Close ensure closed flag set
func (ch *Channel) Close() error {
	if ch.IsClosed() {
		return amqp.ErrClosed
	}

	atomic.StoreInt32(&ch.closed, 1)

	return ch.Channel.Close()
}

// Consume wrap amqp.Channel.Consume, the returned delivery will end only when channel closed by developer
func (ch *Channel) Consume(ctx context.Context, queue, consumer string, autoAck, exclusive, noLocal, noWait bool, args amqp.Table) (<-chan amqp.Delivery, error) {
	deliveries := make(chan amqp.Delivery)

	go func() {
		for {
			d, err := ch.Channel.ConsumeWithContext(ctx, queue, consumer, autoAck, exclusive, noLocal, noWait, args)
			if err != nil {
				ch.log.Error(fmt.Errorf("consume failed, err: %w", err).Error())
				time.Sleep(time.Duration(ch.delay) * time.Second)

				continue
			}

			for msg := range d {
				deliveries <- msg
			}

			// sleep before IsClose call. closed flag may not set before sleep.
			time.Sleep(time.Duration(ch.delay) * time.Second)

			if ch.IsClosed() {
				break
			}
		}
	}()

	return deliveries, nil
}