Localstack

Localstack이란?

• AWS API 를 시뮬레이션 해주는 프레임워크
• 도커 컨테이너 형태로 제공되며, AWS REST API 스펙에 맞는 모킹 http 서버를 실행
• Ref : Overview

Localstack 지원하는 서비스

• Localstack은 Pro 버전과 Community 버전으로 나눠져 있으며 무료로 제공하는 서비스는 아래
  • Kinesis, DynamoDB, DynamoDB Streams, S3, Lambda, SNS, SQS, Redshift, Elasticsearch Service, SES, Route53, CloudWatch, SSM, SecretsManager, STS, IAM, EC2, KMS 등등
• 전체 서비스 목록 : AWS Service Feature Coverage

왜 쓰나요?

• 실제 aws 와 연동하지 않고도 Local 환경에서 aws 서비스를 테스트 가능
• AWS 서비스를 사용하는 인프라 로직의 통합테스트를 작성하기 위해 사용

사전작업

• AWS 커맨드 명령어 로 테스트가 필요하다면 awscli 설치

brew install awscli

• 설치 완료 확인

aws --version

• 테스트용 프로필 등록

$ aws configure --profile default
AWS Access Key ID [None] : test-access-key
AWS Secret Access Key [None] : test-secret-key
Default region name [None] : ap-northeast-2
Default output format [None] : json

• awscli 란?
  • AWS CLI(Command Line Interface)는 AWS 서비스를 관리하는 통합 도구입니다.
  • OS에 AWS CLI를 설치하면 Powershell, Bash와 같은 Shell에서 AWS 서비스를 사용할 수 있습니다.
  • AWS CLI는 플랫폼 중립적이라 모든 OS에서 동일한 명령어로 동작합니다.
  • AWS CLI를 사용하면 Shell에서 (거의)모든 작업을 명령으로 수행할 수 있습니다.
  • 또한 Console에는 없고 AWS CLI로만 사용 가능한 기능도 존재합니다.
  • AWS Console와 AWS CLI는 서로 완전히 대체할 수 없습니다. 즉 두 가지 방식을 모두 활용할 줄 알아야 AWS를 더욱 잘 사용할 수 있습니다.
  • Ref. AWS CLI Command Reference

docker compose 로 localstack 실행하기

• docker-compose.yml : 실행 yml 작성

version: "3.8"

services:
  localstack:
    container_name: 'localstack'
    image: localstack/localstack
    ports:
      - '4566:4566'
    environment:
      - SERVICES=s3,dynamodb,sns,sqs
      - AWS_DEFAULT_REGION=ap-northeast-2
      - HOSTNAME=localhost
      - HOSTNAME_EXTERNAL=localhost
      - LOCALSTACK_HOSTNAME=localhost
      - EDGE_PORT=4566
      - DEBUG=1
    volumes:
      - './init:/docker-entrypoint-initaws.d'

• init.sh : init 스크립트 작성

#!/bin/sh

# s3 버킷 만들기
echo "Init localstack ::: s3"
awslocal s3 mb s3://test-bucket

# dynamodb 테이블 만들기
echo "Init localstack ::: dynamodb"
awslocal dynamodb create-table \
    --table-name user \
    --attribute-definitions \
        AttributeName=mallId,AttributeType=S \
        AttributeName=userId,AttributeType=S \
    --key-schema \
        AttributeName=mallId,KeyType=HASH \
        AttributeName=userId,KeyType=RANGE \
    --provisioned-throughput \
        ReadCapacityUnits=10,WriteCapacityUnits=5 \
    --region ap-northeast-2

# sns 토픽 만들기
echo "Init localstack ::: sns ::: create topics"
lunasoft_topic_arn=$(awslocal sns create-topic --name lunasoft-topic --region ap-northeast-2 --output text)
echo "$lunasoft_topic_arn"
gng_topic_arn=$(awslocal sns create-topic --name gng-topic --region ap-northeast-2 --output text)
echo "$gng_topic_arn"

# sqs 큐 만들기
echo "Init localstack ::: sqs ::: create queues"
dean_queue_url=$(awslocal sqs create-queue --queue-name dean-queue --region ap-northeast-2 --output text)
dean_queue_arn=$(awslocal sqs get-queue-attributes --queue-url "$dean_queue_url" --attribute-names QueueArn --output text | awk '{print $2}')
echo "$dean_queue_arn"
brian_queue_url=$(awslocal sqs create-queue --queue-name brian-queue --region ap-northeast-2 --output text)
brian_queue_arn=$(awslocal sqs get-queue-attributes --queue-url "$brian_queue_url" --attribute-names QueueArn --output text | awk '{print $2}')
echo "$brian_queue_arn"
brandon_queue_url=$(awslocal sqs create-queue --queue-name brandon-queue --region ap-northeast-2 --output text)
brandon_queue_arn=$(awslocal sqs get-queue-attributes --queue-url "$brandon_queue_url" --attribute-names QueueArn --output text | awk '{print $2}')
echo "$brandon_queue_arn"
jacob_queue_url=$(awslocal sqs create-queue --queue-name jacob-queue --region ap-northeast-2 --output text)
jacob_queue_arn=$(awslocal sqs get-queue-attributes --queue-url "$jacob_queue_url" --attribute-names QueueArn --output text | awk '{print $2}')
echo "$jacob_queue_arn"
neo_queue_url=$(awslocal sqs create-queue --queue-name neo-queue --region ap-northeast-2 --output text)
neo_queue_arn=$(awslocal sqs get-queue-attributes --queue-url "$neo_queue_url" --attribute-names QueueArn --output text | awk '{print $2}')
echo "$neo_queue_arn"
harvey_queue_url=$(awslocal sqs create-queue --queue-name harvey-queue --region ap-northeast-2 --output text)
harvey_queue_arn=$(awslocal sqs get-queue-attributes --queue-url "$harvey_queue_url" --attribute-names QueueArn --output text | awk '{print $2}')
echo "$harvey_queue_arn"

# sns 구독 설정하기
echo "Init localstack ::: create subscriptions"
subscription1_arn=$(awslocal sns subscribe --topic-arn "$lunasoft_topic_arn" --protocol sqs --notification-endpoint "$dean_queue_arn" --output text)
echo "$subscription1_arn"
subscription2_arn=$(awslocal sns subscribe --topic-arn "$lunasoft_topic_arn" --protocol sqs --notification-endpoint "$brian_queue_arn" --output text)
echo "$subscription2_arn"
subscription3_arn=$(awslocal sns subscribe --topic-arn "$lunasoft_topic_arn" --protocol sqs --notification-endpoint "$brandon_queue_arn" --output text)
echo "$subscription3_arn"
subscription4_arn=$(awslocal sns subscribe --topic-arn "$gng_topic_arn" --protocol sqs --notification-endpoint "$jacob_queue_arn" --output text)
echo "$subscription4_arn"
subscription5_arn=$(awslocal sns subscribe --topic-arn "$gng_topic_arn" --protocol sqs --notification-endpoint "$neo_queue_arn" --output text)
echo "$subscription5_arn"
subscription6_arn=$(awslocal sns subscribe --topic-arn "$gng_topic_arn" --protocol sqs --notification-endpoint "$harvey_queue_arn" --output text)
echo "$subscription6_arn"

# sns 구독 속성 설정하기
echo "Init localstack ::: set subscription attributes"
awslocal sns set-subscription-attributes --subscription-arn $subscription1_arn --attribute-name RawMessageDelivery --attribute-value true
awslocal sns set-subscription-attributes --subscription-arn $subscription2_arn --attribute-name RawMessageDelivery --attribute-value true
awslocal sns set-subscription-attributes --subscription-arn $subscription3_arn --attribute-name RawMessageDelivery --attribute-value true
awslocal sns set-subscription-attributes --subscription-arn $subscription4_arn --attribute-name RawMessageDelivery --attribute-value true
awslocal sns set-subscription-attributes --subscription-arn $subscription5_arn --attribute-name RawMessageDelivery --attribute-value true
awslocal sns set-subscription-attributes --subscription-arn $subscription6_arn --attribute-name RawMessageDelivery --attribute-value true

• 정상 구동 확인

  • http://localhost:4566/health 접속 후 구동 확인
    

• 로컬에서 awscli로 정상 구동 확인하기

• s3 버킷 리스트 확인

aws s3 ls --endpoint-url=http://localhost:4566

• dynamodb 테이블 확인

aws dynamodb list-tables --endpoint-url=http://localhost:4566 --region ap-northeast-2

• sns 토픽 리스트 확인

aws sns list-topics --endpoint-url=http://localhost:4566 --region=ap-northeast-2

• sqs 큐 리스트 확인

aws sqs list-queues --endpoint-url=http://localhost:4566 --region=ap-northeast-2

• sns 구독 정보 확인

aws sns list-subscriptions --endpoint-url=http://localhost:4566 --region=ap-northeast-2

Localstack 테스트용 Sample Java Project

• 필요한 library 추가 (SpringBoot project에서는 maven 이나 gradle로 구성)
  

AWS S3 : 코드 작성

import com.amazonaws.SdkClientException;
import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.client.builder.AwsClientBuilder;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.AmazonS3Exception;
import com.amazonaws.services.s3.model.CannedAccessControlList;
import com.amazonaws.services.s3.model.ObjectMetadata;
import com.amazonaws.services.s3.model.PutObjectRequest;
import com.amazonaws.services.s3.model.S3Object;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.text.SimpleDateFormat;
import java.util.Date;

public class LocalstackS3Test {

    private static final String _ACCESS_KEY = "test-access-key";
    private static final String _SECRET_KEY = "test-secret-key";
    private static final String _ENDPOINT = "http://localhost:4566";
    private static final String _REGION = "ap-northeast-2";
    private static final String _S3_BUCKET_NAME = "test-bucket";
    private static final String _LOCAL_FILE_PATH = "file";

    public static void main(String[] args) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddhhmmss");
        String now = sdf.format(new Date());

        File file = new File(_LOCAL_FILE_PATH + "/sample.txt");
        String fileKey = now + "_" + file.getName();

        // credentials
        AWSCredentials credentials = new BasicAWSCredentials(_ACCESS_KEY, _SECRET_KEY);
        AwsClientBuilder.EndpointConfiguration config = new AwsClientBuilder.EndpointConfiguration(_ENDPOINT, _REGION);
        AmazonS3 amazonS3 = AmazonS3ClientBuilder.standard()
                .withEndpointConfiguration(config)
                .withPathStyleAccessEnabled(true)
                .withCredentials(new AWSStaticCredentialsProvider(credentials))
                .build();

        // s3 업로드
        uploadToAWS(amazonS3, file, fileKey);

        // s3 다운로드
        downloadToAWS(amazonS3, file.getAbsolutePath(), fileKey);

        // s3 이름변경
        renameToAWS(amazonS3, fileKey, "test-file-key.txt");

        // s3 삭제
        removeToAWS(amazonS3, fileKey);
    }

    public static void uploadToAWS(AmazonS3 amazonS3, File file, String fileKey) {
        try {
            ObjectMetadata metadata = new ObjectMetadata();
            metadata.setContentType("plain/text");
            PutObjectRequest request = new PutObjectRequest(_S3_BUCKET_NAME, fileKey, file);
            request.setMetadata(metadata);
            request.withCannedAcl(CannedAccessControlList.AuthenticatedRead);
            amazonS3.putObject(request);
            System.out.println("upload success : " + fileKey);
        } catch (SdkClientException e) {
            System.out.println("upload fail : " + e.getMessage());
        }
    }

    public static void downloadToAWS(AmazonS3 amazonS3, String filePath, String fileKey) {
        try {
            S3Object fullObject = amazonS3.getObject(_S3_BUCKET_NAME, fileKey);
            InputStream in = fullObject.getObjectContent();
            Files.copy(in, Paths.get(filePath + fileKey));
            System.out.println("download success : " + fileKey);
        } catch (AmazonS3Exception e) {
            System.out.println("download fail : " + e.getMessage());
        } catch (IOException e) {
            System.out.println("file copy fail : " + e.getMessage());
        }
    }

    public static void renameToAWS(AmazonS3 amazonS3, String sourceKey, String destinationKey) {
        try {
            amazonS3.copyObject(_S3_BUCKET_NAME, sourceKey, _S3_BUCKET_NAME, destinationKey);
            amazonS3.deleteObject(_S3_BUCKET_NAME, sourceKey);
            System.out.println("rename success : " + sourceKey + " to " + destinationKey);
        } catch (SdkClientException e) {
            System.out.println("rename fail : " + e.getMessage());
        }
    }

    public static void removeToAWS(AmazonS3 amazonS3, String fileKey) {
        try {
            amazonS3.deleteObject(_S3_BUCKET_NAME, fileKey);
            System.out.println("remove success : " + fileKey);
        } catch (SdkClientException e) {
            System.out.println("remove fail : " + e.getMessage());
        }
    }

}

AWS S3 : aws-cli 를 통한 확인

• 버킷 리스트 조회

aws s3 ls --endpoint-url=http://localhost:4566

• 버킷 파일 조회

aws s3 ls s3://test-bucket --endpoint-url=http://localhost:4566

AWS DynamoDB : 코드 작성

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.client.builder.AwsClientBuilder;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClientBuilder;
import com.amazonaws.services.dynamodbv2.document.DynamoDB;
import com.amazonaws.services.dynamodbv2.document.Item;
import com.amazonaws.services.dynamodbv2.document.ItemCollection;
import com.amazonaws.services.dynamodbv2.document.QueryOutcome;
import com.amazonaws.services.dynamodbv2.document.Table;
import com.amazonaws.services.dynamodbv2.document.spec.QuerySpec;
import com.amazonaws.services.dynamodbv2.document.utils.ValueMap;
import com.amazonaws.services.dynamodbv2.model.AttributeValue;
import com.amazonaws.services.dynamodbv2.model.DeleteItemRequest;
import com.amazonaws.services.dynamodbv2.model.DeleteItemResult;
import com.amazonaws.services.dynamodbv2.model.GetItemRequest;
import com.amazonaws.services.dynamodbv2.model.GetItemResult;
import com.amazonaws.services.dynamodbv2.model.PutItemRequest;
import com.amazonaws.services.dynamodbv2.model.PutItemResult;

import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;

public class LocalstackDynamoDBTest {

    private static final String _ACCESS_KEY = "test-access-key";
    private static final String _SECRET_KEY = "test-secret-key";
    private static final String _ENDPOINT = "http://localhost:4566";
    private static final String _REGION = "ap-northeast-2";

    private static final String _TABLE_NAME = "user";
    private static final String _MALL_ID = "10";
    private static final String _USER_ID = "test-user-id";
    private static final String _CONTENT = "test contents";

    public static void main(String[] args) {
        // credentials
        AWSCredentials credentials = new BasicAWSCredentials(_ACCESS_KEY, _SECRET_KEY);
        AwsClientBuilder.EndpointConfiguration config = new AwsClientBuilder.EndpointConfiguration(_ENDPOINT, _REGION);
        AmazonDynamoDB amazonDynamoDB = AmazonDynamoDBClientBuilder.standard()
                .withEndpointConfiguration(config)
                .withCredentials(new AWSStaticCredentialsProvider(credentials))
                .build();

        // table list 출력
        getTableList(amazonDynamoDB);

        // item 등록
        putItem(amazonDynamoDB);

        // item 조회 (key)
        getItemByKey(amazonDynamoDB);

        // item 조회 (query)
        getItemByQuery(amazonDynamoDB);

        // item 삭제
//        removeItem(amazonDynamoDB);
    }

    public static void getTableList(AmazonDynamoDB amazonDynamoDB) {
        List<String> tableNames = amazonDynamoDB.listTables().getTableNames();
        System.out.println("========== TABLE LIST ==========");
        for (String tableName : tableNames) {
            System.out.println(tableName);
        }
        System.out.println("================================");
    }

    public static void putItem(AmazonDynamoDB amazonDynamoDB) {
        Map<String, AttributeValue> item = new HashMap<>();
        item.put("mallId", (new AttributeValue()).withS(_MALL_ID));
        item.put("userId", (new AttributeValue()).withS(_USER_ID));
        item.put("content", (new AttributeValue()).withS(_CONTENT));
        item.put("deleted", (new AttributeValue()).withBOOL(false));
        item.put("createdAt", (new AttributeValue()).withS("2023-02-06T02:21:30.536Z"));

        PutItemRequest putItemRequest = (new PutItemRequest())
                .withTableName(_TABLE_NAME)
                .withItem(item);

        PutItemResult putItemResult = amazonDynamoDB.putItem(putItemRequest);
        if (200 == putItemResult.getSdkHttpMetadata().getHttpStatusCode()) {
            System.out.println("[success] put item");
        } else {
            System.out.println("[fail] put item");
        }
    }

    public static void getItemByKey(AmazonDynamoDB amazonDynamoDB) {
        Map<String, AttributeValue> key = new HashMap<>();
        key.put("mallId", (new AttributeValue()).withS(_MALL_ID));
        key.put("userId", (new AttributeValue()).withS(_USER_ID));

        GetItemRequest getItemRequest = (new GetItemRequest())
                .withTableName(_TABLE_NAME)
                .withKey(key);

        GetItemResult getItemResult = amazonDynamoDB.getItem(getItemRequest);

        Map<String, AttributeValue> result = getItemResult.getItem();
        String mallId = result.get("mallId").getS();
        String userId = result.get("userId").getS();
        String content = result.get("content").getS();
        boolean deleted = result.get("deleted").getBOOL();
        String createdAt = result.get("createdAt").getS();

        System.out.println("======== GET ITEM BY KEY ========");
        System.out.println("mallId : " + mallId);
        System.out.println("userId : " + userId);
        System.out.println("content : " + content);
        System.out.println("deleted : " + deleted);
        System.out.println("createdAt : " + createdAt);
        System.out.println("================================");
    }

    public static void getItemByQuery(AmazonDynamoDB amazonDynamoDB) {
        DynamoDB dynamoDB = new DynamoDB(amazonDynamoDB);
        Table user = dynamoDB.getTable(_TABLE_NAME);

        QuerySpec spec = new QuerySpec()
                .withKeyConditionExpression("mallId = :mallId and userId = :userId")
                .withFilterExpression("content = :content")
                .withValueMap(new ValueMap()
                        .withString(":mallId", _MALL_ID)
                        .withString(":userId", _USER_ID)
                        .withString(":content", _CONTENT))
                .withConsistentRead(true);
        ItemCollection<QueryOutcome> items = user.query(spec);

        Iterator<Item> iterator = items.iterator();
        Item item = null;
        while (iterator.hasNext()) {
            item = iterator.next();
            long mallId = item.getLong("mallId");
            String userId = item.getString("userId");
            String content = item.getString("content");
            boolean deleted = item.getBOOL("deleted");
            String createdAt = item.getString("createdAt");

            System.out.println("======= GET ITEM BY QUERY =======");
            System.out.println("mallId : " + mallId);
            System.out.println("userId : " + userId);
            System.out.println("content : " + content);
            System.out.println("deleted : " + deleted);
            System.out.println("createdAt : " + createdAt);
            System.out.println("================================");
        }
    }

    public static void removeItem(AmazonDynamoDB amazonDynamoDB) {
        Map<String, AttributeValue> key = new HashMap<>();
        key.put("mallId", (new AttributeValue()).withS(_MALL_ID));
        key.put("userId", (new AttributeValue()).withS(_USER_ID));

        DeleteItemRequest deleteItemRequest = (new DeleteItemRequest())
                .withTableName(_TABLE_NAME)
                .withKey(key);

        DeleteItemResult deleteItemResult = amazonDynamoDB.deleteItem(deleteItemRequest);

        if (200 == deleteItemResult.getSdkHttpMetadata().getHttpStatusCode()) {
            System.out.println("[success] delete item");
        } else {
            System.out.println("[fail] delete item");
        }
    }

}

AWS DynamoDB : aws-cli 를 통한 확인

aws dynamodb query \
    --table-name user \
    --key-condition-expression "mallId = :mallId and userId = :userId" \
    --expression-attribute-values  '{":mallId":{"S":"10"},":userId":{"S":"test-user-id"}}' \
    --endpoint-url=http://localhost:4566 \
    --region ap-northeast-2

AWS SNS : 코드 작성

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.client.builder.AwsClientBuilder;
import com.amazonaws.services.sns.AmazonSNS;
import com.amazonaws.services.sns.AmazonSNSClientBuilder;
import com.amazonaws.services.sns.model.PublishRequest;
import com.amazonaws.services.sns.model.PublishResult;

import java.text.SimpleDateFormat;
import java.util.Date;

public class LocalstackSnsTest {

    private static final String _ACCESS_KEY = "test-access-key";
    private static final String _SECRET_KEY = "test-secret-key";
    private static final String _ENDPOINT = "http://localhost:4566";
    private static final String _REGION = "ap-northeast-2";

    private static final String _LUNA_TOPIC = "arn:aws:sns:ap-northeast-2:000000000000:lunasoft-topic";
    private static final String _GNG_TOPIC = "arn:aws:sns:ap-northeast-2:000000000000:gng-topic";

    public static void main(String[] args) {
        // credentials
        AWSCredentials credentials = new BasicAWSCredentials(_ACCESS_KEY, _SECRET_KEY);
        AwsClientBuilder.EndpointConfiguration config = new AwsClientBuilder.EndpointConfiguration(_ENDPOINT, _REGION);
        AmazonSNS amazonSNS = AmazonSNSClientBuilder.standard()
                .withEndpointConfiguration(config)
                .withCredentials(new AWSStaticCredentialsProvider(credentials))
                .build();

        // send message
        sendMessage(amazonSNS, _LUNA_TOPIC);
        sendMessage(amazonSNS, _GNG_TOPIC);
    }

    private static void sendMessage(AmazonSNS amazonSNS, String topicArn) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddhhmmss");
        String now = sdf.format(new Date());
        String message = "SAMPLE:::" + now;

        PublishResult publishResult = amazonSNS.publish(new PublishRequest()
                .withTopicArn(topicArn)
                .withMessage(message));
        if (200 == publishResult.getSdkHttpMetadata().getHttpStatusCode()) {
            System.out.println("[success] send message ::: " + topicArn);
        } else {
            System.out.println("[fail] send message ::: " + topicArn);
        }
    }

}

AWS SQS : 코드 작성

import com.amazonaws.auth.AWSCredentials;
import com.amazonaws.auth.AWSStaticCredentialsProvider;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.client.builder.AwsClientBuilder;
import com.amazonaws.services.sqs.AmazonSQS;
import com.amazonaws.services.sqs.AmazonSQSClientBuilder;
import com.amazonaws.services.sqs.model.Message;

import java.util.List;

public class LocalstackSqsTest {

    private static final String _ACCESS_KEY = "test-access-key";
    private static final String _SECRET_KEY = "test-secret-key";
    private static final String _ENDPOINT = "http://localhost:4566";
    private static final String _REGION = "ap-northeast-2";

    private static final String _DEAN_QUEUE = "http://localhost:4566/000000000000/dean-queue";
    private static final String _BRIAN_QUEUE = "http://localhost:4566/000000000000/brian-queue";
    private static final String _BRANDON_QUEUE = "http://localhost:4566/000000000000/brandon-queue";
    private static final String _JACOB_QUEUE = "http://localhost:4566/000000000000/jacob-queue";
    private static final String _NEO_QUEUE = "http://localhost:4566/000000000000/neo-queue";
    private static final String _HARVEY_QUEUE = "http://localhost:4566/000000000000/harvey-queue";

    public static void main(String[] args) {
        // credentials
        AWSCredentials credentials = new BasicAWSCredentials(_ACCESS_KEY, _SECRET_KEY);
        AwsClientBuilder.EndpointConfiguration config = new AwsClientBuilder.EndpointConfiguration(_ENDPOINT, _REGION);
        AmazonSQS amazonSQS = AmazonSQSClientBuilder.standard()
                .withEndpointConfiguration(config)
                .withCredentials(new AWSStaticCredentialsProvider(credentials))
                .build();

        // receive message
        while (true) {
            receiveMessage(amazonSQS, _DEAN_QUEUE);
            receiveMessage(amazonSQS, _BRIAN_QUEUE);
            receiveMessage(amazonSQS, _BRANDON_QUEUE);
            receiveMessage(amazonSQS, _JACOB_QUEUE);
            receiveMessage(amazonSQS, _NEO_QUEUE);
            receiveMessage(amazonSQS, _HARVEY_QUEUE);
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }

    private static void receiveMessage(AmazonSQS amazonSQS, String queueUrl) {
        List<Message> messages = amazonSQS.receiveMessage(queueUrl).getMessages();
        for (Message message : messages) {
            System.out.println("url : " + queueUrl + ", id : " + message.getMessageId() + ", body : " + message.getBody());
            amazonSQS.deleteMessage(queueUrl, message.getReceiptHandle());
        }
    }

}