Spring 20: 클라우드 - AWS 연동

주요 기능

Maven 의존성 설정

<dependencies>
    <!-- Spring Cloud AWS Core -->
    <dependency>
        <groupId>io.awspring.cloud</groupId>
        <artifactId>spring-cloud-aws-starter</artifactId>
        <version>3.0.3</version>
    </dependency>
    
    <!-- Spring Cloud AWS S3 -->
    <dependency>
        <groupId>io.awspring.cloud</groupId>
        <artifactId>spring-cloud-aws-starter-s3</artifactId>
        <version>3.0.3</version>
    </dependency>
    
    <!-- Spring Cloud AWS SQS -->
    <dependency>
        <groupId>io.awspring.cloud</groupId>
        <artifactId>spring-cloud-aws-starter-sqs</artifactId>
        <version>3.0.3</version>
    </dependency>
    
    <!-- AWS SDK v2 -->
    <dependency>
        <groupId>software.amazon.awssdk</groupId>
        <artifactId>bom</artifactId>
        <version>2.21.29</version>
        <type>pom</type>
        <scope>import</scope>
    </dependency>
</dependencies>

기본 AWS 설정 클래스

@Configuration
@EnableConfigurationProperties
public class AwsConfig {

    @Bean
    @Primary
    public AwsCredentialsProvider awsCredentialsProvider() {
        return DefaultCredentialsProvider.create();
    }

    @Bean
    public Region awsRegion() {
        return Region.AP_NORTHEAST_2; // 서울 리전
    }

    @Bean
    public S3Client s3Client(AwsCredentialsProvider credentialsProvider, Region region) {
        return S3Client.builder()
                .credentialsProvider(credentialsProvider)
                .region(region)
                .build();
    }

    @Bean
    public SqsClient sqsClient(AwsCredentialsProvider credentialsProvider, Region region) {
        return SqsClient.builder()
                .credentialsProvider(credentialsProvider)
                .region(region)
                .build();
    }

    @Bean
    public SnsClient snsClient(AwsCredentialsProvider credentialsProvider, Region region) {
        return SnsClient.builder()
                .credentialsProvider(credentialsProvider)
                .region(region)
                .build();
    }
}

파일 다운로드 서비스

@Service
@RequiredArgsConstructor
@Slf4j
public class S3DownloadService {
    
    private final S3Client s3Client;
    private final S3Properties s3Properties;
    
    public ResponseEntity<Resource> downloadFile(String fileName) {
        try {
            GetObjectRequest getObjectRequest = GetObjectRequest.builder()
                    .bucket(s3Properties.getBucket())
                    .key(fileName)
                    .build();
            
            ResponseInputStream<GetObjectResponse> s3Object = 
                s3Client.getObject(getObjectRequest);
            
            byte[] content = s3Object.readAllBytes();
            ByteArrayResource resource = new ByteArrayResource(content);
            
            return ResponseEntity.ok()
                    .contentType(MediaType.parseMediaType(
                        s3Object.response().contentType()))
                    .contentLength(content.length)
                    .header(HttpHeaders.CONTENT_DISPOSITION, 
                        "attachment; filename="" + fileName + """)
                    .body(resource);
                    
        } catch (NoSuchKeyException e) {
            log.error("파일을 찾을 수 없습니다: {}", fileName);
            throw new FileNotFoundException("파일을 찾을 수 없습니다: " + fileName);
        } catch (Exception e) {
            log.error("파일 다운로드 실패: {}", fileName, e);
            throw new RuntimeException("파일 다운로드에 실패했습니다.", e);
        }
    }
    
    public InputStream getFileStream(String fileName) {
        try {
            GetObjectRequest getObjectRequest = GetObjectRequest.builder()
                    .bucket(s3Properties.getBucket())
                    .key(fileName)
                    .build();
            
            return s3Client.getObject(getObjectRequest);
            
        } catch (Exception e) {
            throw new RuntimeException("파일 스트림 획득 실패", e);
        }
    }
    
    public boolean fileExists(String fileName) {
        try {
            HeadObjectRequest headObjectRequest = HeadObjectRequest.builder()
                    .bucket(s3Properties.getBucket())
                    .key(fileName)
                    .build();
            
            s3Client.headObject(headObjectRequest);
            return true;
            
        } catch (NoSuchKeyException e) {
            return false;
        } catch (Exception e) {
            log.error("파일 존재 확인 실패: {}", fileName, e);
            return false;
        }
    }
}

다운로드 컨트롤러

@RestController
@RequestMapping("/api/files")
@RequiredArgsConstructor
public class FileDownloadController {
    
    private final S3DownloadService s3DownloadService;
    
    @GetMapping("/download/{fileName}")
    public ResponseEntity<Resource> downloadFile(@PathVariable String fileName) {
        
        if (!s3DownloadService.fileExists(fileName)) {
            return ResponseEntity.notFound().build();
        }
        
        return s3DownloadService.downloadFile(fileName);
    }
    
    @GetMapping("/stream/{fileName}")
    public ResponseEntity<StreamingResponseBody> streamFile(@PathVariable String fileName) {
        
        if (!s3DownloadService.fileExists(fileName)) {
            return ResponseEntity.notFound().build();
        }
        
        StreamingResponseBody stream = outputStream -> {
            try (InputStream inputStream = s3DownloadService.getFileStream(fileName)) {
                IOUtils.copy(inputStream, outputStream);
            } catch (Exception e) {
                throw new RuntimeException("파일 스트리밍 실패", e);
            }
        };
        
        return ResponseEntity.ok()
                .contentType(MediaType.APPLICATION_OCTET_STREAM)
                .header(HttpHeaders.CONTENT_DISPOSITION, 
                    "attachment; filename="" + fileName + """)
                .body(stream);
    }
}