AWS SSQ API, Implementation, and Stub in Go

 

In this post we will present a to send messages to AWS SQS. We will include an interface, an implementation, and a stub. We've previously included an example for producer and consumer in Go, and here we provide a nice API that enables us to use this code both in production and in tests.

The interface is the minimal API required to send a message. In this interface we hide the AWS session connection, as well as the AWS SQS queue name, and include only the message details.

type SqsApi interface {
  SendMessage(
   attributes map[string]string,
   data string,
  )
}

The implementation uses an AWS session. Notice that there are several methods to get an AWS session, but in this implementation we use the simplest method.

package awssqs

import (
  "github.com/aws/aws-sdk-go/aws"
  "github.com/aws/aws-sdk-go/aws/session"
  "github.com/aws/aws-sdk-go/service/sqs"
)

type SqsImpl struct {
  sqsClient *sqs.SQS
  queueUrl  string
}

func ProduceAwsSqsImpl(
  queueUrl string,
) *SqsImpl {
  awsSession, err := session.NewSession()
  if err!= nil{
   panic(err)
  }

  return &SqsImpl{
   sqsClient: sqs.New(awsSession),
   queueUrl:  queueUrl,
  }
}

func (s *SqsImpl) SendMessage(
  attributes map[string]string,
  data string,
) {
  input := sqs.SendMessageInput{
   MessageAttributes: make(map[string]*sqs.MessageAttributeValue),
   MessageBody:       aws.String(data),
   QueueUrl:          aws.String(s.queueUrl),
  }

  for key, value := range attributes {
   input.MessageAttributes[key] = &sqs.MessageAttributeValue{
    DataType:    aws.String("String"),
    StringValue: aws.String(value),
   }
  }

  _, err := s.sqsClient.SendMessage(&input)
  if err!= nil{
   panic(err)
  }
}

We also include a stub that can be used during tests:

type MessageData struct {
  Attributes map[string]string
  Data       string
}

type SqsStub struct {
  Messages []*MessageData
}

func ProduceAwsSqsStub() *SqsStub {
  return &SqsStub{}
}

func (s *SqsStub) SendMessage(
  attributes map[string]string,
  data string,
) {
  messageData := MessageData{
   Attributes: attributes,
   Data:       data,
  }
  s.Messages = append(s.Messages, &messageData)
}