/
sqs.go
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/
sqs.go
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/*
Copyright 2021 Adevinta
*/
package queue
import (
"context"
"encoding/json"
"errors"
"runtime/debug"
"sync"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/arn"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/sqs"
"github.com/aws/aws-sdk-go/service/sqs/sqsiface"
log "github.com/sirupsen/logrus"
)
const (
maxNumberOfMsg = 10
defSQSWaitTime = 0
)
// SQSConfig is the configuration required for an SQSConsumer.
type SQSConfig struct {
QueueArn string `toml:"queue_arn"`
Timeout int64 `toml:"timeout"`
MaxWaitTime int64 `toml:"wait_time"`
QueueName string `toml:"queue_name"`
Endpoint string `toml:"endpoint"`
}
// SQSConsumer is the SQS implementation of the QueueConsumer interface.
type SQSConsumer struct {
config SQSConfig
sqsURL string
sqsWaitTime int64
sqs sqsiface.SQSAPI
processor Processor
logger *log.Logger
}
// SQSConsumerGroup is a group of SQSConsumers.
type SQSConsumerGroup struct {
consumers []*SQSConsumer
}
// NewSQSConsumerGroup creates a new SQSConsumerGroup.
func NewSQSConsumerGroup(nConsumers uint8, config SQSConfig, processor Processor, logger *log.Logger) (*SQSConsumerGroup, error) {
var consumerGroup SQSConsumerGroup
awsSess, err := session.NewSession()
if err != nil {
return nil, err
}
arn, err := arn.Parse(config.QueueArn)
if err != nil {
return nil, err
}
awsCfg := aws.NewConfig()
if arn.Region != "" {
awsCfg = awsCfg.WithRegion(arn.Region)
}
if config.Endpoint != "" {
awsCfg = awsCfg.WithEndpoint(config.Endpoint)
}
input := sqs.GetQueueUrlInput{
QueueName: aws.String(arn.Resource),
}
if arn.AccountID != "" {
input.SetQueueOwnerAWSAccountId(arn.AccountID)
}
sqsSvc := sqs.New(awsSess, awsCfg)
sqsURLData, err := sqsSvc.GetQueueUrl(&input)
if err != nil {
return nil, err
}
var consumers []*SQSConsumer
for i := uint8(0); i < nConsumers; i++ {
consumers = append(consumers, &SQSConsumer{
config: config,
sqsURL: *sqsURLData.QueueUrl,
sqsWaitTime: defSQSWaitTime,
sqs: sqsSvc,
processor: processor,
logger: logger,
})
}
consumerGroup.consumers = consumers
return &consumerGroup, nil
}
// Start makes the consumer group start reading and processing messages from the queue.
func (g *SQSConsumerGroup) Start(ctx context.Context, wg *sync.WaitGroup) {
for _, consumer := range g.consumers {
wg.Add(1)
go consumer.start(ctx, wg)
}
}
func (c *SQSConsumer) start(ctx context.Context, wg *sync.WaitGroup) {
defer func() {
if err := recover(); err != nil {
c.logger.WithFields(log.Fields{
"err": err,
"trace": string(debug.Stack()),
}).Error("Consumer stopping due to panic err")
}
wg.Done()
}()
for {
select {
case <-ctx.Done():
return
default:
if err := c.readAndProcess(ctx); err != nil {
c.logger.WithError(err).Error("Error reading SQS messages")
}
}
}
}
func (c *SQSConsumer) readAndProcess(ctx context.Context) error {
mssgs, err := c.readMssgs(ctx)
if err != nil {
return err
}
// Adjust SQS wait time based on
// number of retrieved messages
if len(mssgs) == 0 {
c.sqsWaitTime = c.config.MaxWaitTime
} else {
c.sqsWaitTime = defSQSWaitTime
}
for _, mssg := range mssgs {
// Check for invalid mssg
mssgBody, err := validateMssg(mssg)
if err != nil {
c.logger.WithError(err).WithFields(log.Fields{
"mssg": mssg,
}).Error("Invalid SQS message")
if err = c.deleteMessage(mssg); err != nil {
c.logger.WithError(err).Error("Error deleting processed message")
}
continue
}
// If message is valid, process it
if err = c.processor.ProcessMessage(mssgBody); err != nil {
c.logger.WithError(err).WithFields(log.Fields{
"body": mssgBody,
"attrs": mssg.Attributes,
}).Error("Error processing SQS message")
continue
}
// Delete it
if err = c.deleteMessage(mssg); err != nil {
c.logger.WithError(err).Error("Error deleting processed message")
}
}
return nil
}
func (c *SQSConsumer) readMssgs(ctx context.Context) ([]*sqs.Message, error) {
receiveQuery := sqs.ReceiveMessageInput{
QueueUrl: aws.String(c.sqsURL),
MaxNumberOfMessages: aws.Int64(maxNumberOfMsg),
WaitTimeSeconds: aws.Int64(c.sqsWaitTime),
VisibilityTimeout: aws.Int64(c.config.Timeout),
AttributeNames: []*string{
aws.String(sqs.QueueAttributeNameAll),
},
}
mssgsResp, err := c.sqs.ReceiveMessageWithContext(ctx, &receiveQuery)
if err != nil {
return nil, err
}
return mssgsResp.Messages, nil
}
func (c *SQSConsumer) deleteMessage(mssg *sqs.Message) error {
_, err := c.sqs.DeleteMessage(&sqs.DeleteMessageInput{
ReceiptHandle: mssg.ReceiptHandle,
QueueUrl: aws.String(c.sqsURL),
})
return err
}
func validateMssg(mssg *sqs.Message) (string, error) {
if mssg == nil || mssg.Body == nil {
return "", errors.New("unpexpected nil message")
}
return removeSNSEnvelope(*mssg.Body)
}
// removeSNSEnvelope removes the SNS envelope around the
// actual body message because messages received in queue
// are pushed through an SNS topic.
func removeSNSEnvelope(snsNotif string) (string, error) {
var mold = struct {
Message string `json:"Message"`
}{}
if err := json.Unmarshal([]byte(snsNotif), &mold); err != nil {
return "", errors.New("unexpected mssg format: Expected SNS envelope")
}
return mold.Message, nil
}