sqs.go

package sqs

/*Package sqs provides a simple interface to send messages to AWS SQS*/

import (
	"encoding/binary"
	"encoding/json"
	"fmt"
	"github.com/google/uuid"
	"gitlab.com/uafrica/go-utils/s3"
	"gitlab.com/uafrica/go-utils/string_utils"
	"io/ioutil"
	"time"

	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/sqs"
	"gitlab.com/uafrica/go-utils/logs"
)

var sqsClient *sqs.SQS

const SQSMessageOnS3Key = "message-on-s3"

// Messenger sends an arbitrary message via SQS
type Messenger struct {
	QueueName          string
	QueueURL           string
	Region             string
	S3Session          *s3.SessionWithHelpers
	S3BucketName       string
	MessageGroupID     *string
	RequestIDHeaderKey string
}

// NewSQSClient constructs a Messenger which sends messages to an SQS queue
// awsRegion - region that the queue was created
// awsQueue - name of the queue
// Note: Calling code needs SQS IAM permissions
func NewSQSClient(awsRegion string) (*sqs.SQS, error) {
	// Make an AWS session
	sess, err := session.NewSessionWithOptions(session.Options{
		Config: aws.Config{
			Region: aws.String(awsRegion),
		},
	})

	if err != nil {
		return nil, err
	}

	// Create SQS service
	sqsClient = sqs.New(sess)
	return sqsClient, err
}

// SendSQSMessage sends a message to the queue associated with the messenger
// headers - string message attributes of the SQS message (see AWS SQS documentation)
// body - body of the SQS message (see AWS SQS documentation)
func (m *Messenger) SendSQSMessage(headers map[string]string, body string, currentRequestID *string, sqsType string) (string, error) {
	msgAttrs := make(map[string]*sqs.MessageAttributeValue)

	for key, val := range headers {
		msgAttrs[key] = &sqs.MessageAttributeValue{
			DataType:    aws.String("String"),
			StringValue: aws.String(val),
		}
	}

	// Add request ID
	if currentRequestID != nil {
		msgAttrs[m.RequestIDHeaderKey] = &sqs.MessageAttributeValue{
			DataType:    aws.String("String"),
			StringValue: aws.String(*currentRequestID),
		}
	}

	msgAttrs["type"] = &sqs.MessageAttributeValue{
		DataType:    aws.String("String"),
		StringValue: aws.String(sqsType),
	}

	var res *sqs.SendMessageOutput
	var err error
	if string_utils.UnwrapString(m.MessageGroupID) == "" {
		res, err = sqsClient.SendMessage(&sqs.SendMessageInput{
			MessageAttributes: msgAttrs,
			MessageBody:       aws.String(body),
			QueueUrl:          &m.QueueURL,
		})
	} else {
		res, err = sqsClient.SendMessage(&sqs.SendMessageInput{
			MessageAttributes: msgAttrs,
			MessageBody:       aws.String(body),
			QueueUrl:          &m.QueueURL,
			MessageGroupId:    m.MessageGroupID,
		})
	}

	if err != nil {
		return "", err
	}

	return *res.MessageId, err
}

func SendSQSMessage(msgr Messenger, objectToSend interface{}, currentRequestID *string, sqsType string) error {
	if sqsClient == nil {
		var err error
		sqsClient, err = NewSQSClient(msgr.Region)
		if err != nil {
			logs.ErrorWithMsg("Failed to create sqs client", err)
		}
	}

	jsonBytes, err := json.Marshal(objectToSend)
	if err != nil {
		logs.ErrorWithMsg("Failed to encode sqs event data", err)
		return err
	}

	message := string(jsonBytes)
	headers := map[string]string{
		"Name":            "dummy",
		SQSMessageOnS3Key: "false",
	}

	// If bigger than 200 KB upload message to s3 and send s3 file name to sqs
	// The sqs receiver should check the header to see if the message is in the body or on s3
	if binary.Size(message) > 0 {
		headers[SQSMessageOnS3Key] = "true"
		id := uuid.New()
		filename := fmt.Sprintf("%v-%v", sqsType, id.String())

		err := uploadMessageToS3(msgr.S3Session, msgr.S3BucketName, filename, message)
		if err != nil {
			return err
		}
	}

	msgID, err := msgr.SendSQSMessage(headers, message, currentRequestID, sqsType)
	if err != nil {
		logs.ErrorWithMsg("Failed to send sqs event", err)
		return err
	}

	logs.Info(fmt.Sprintf("Sent SQS message to %s with ID %s", msgr.QueueName, msgID))
	return nil
}

func uploadMessageToS3(session *s3.SessionWithHelpers, bucket string, name string, object interface{}) error {
	messageBytes, err := json.Marshal(object)
	if err != nil {
		return err
	}

	// Upload message
	expiry := 24 * 7 * time.Hour // 3 days
	_, err = session.UploadWithSettings(messageBytes, bucket, name, s3.S3UploadSettings{
		ExpiryDuration: &expiry,
	})
	if err != nil {
		return err
	}

	return nil
}

func RetrieveMessageFromS3(session *s3.SessionWithHelpers, bucket string, filename string) ([]byte, error) {
	// get the file contents
	rawObject, err := session.GetObject(bucket, filename, false)
	if err != nil {
		return []byte{}, err
	}

	// Read the message
	var bodyBytes []byte
	bodyBytes, err = ioutil.ReadAll(rawObject.Body)
	if err != nil {
		logs.ErrorWithMsg("Could not read file", err)
		return []byte{}, err
	}

	return bodyBytes, nil
}