Use GetBucketEncryption with an AWS SDK

Get the encryption configuration of a directory bucket.

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.GetBucketEncryptionRequest;
import software.amazon.awssdk.services.s3.model.GetBucketEncryptionResponse;
import software.amazon.awssdk.services.s3.model.S3Exception;
import software.amazon.awssdk.services.s3.model.ServerSideEncryptionRule;

import static com.example.s3.util.S3DirectoryBucketUtils.createDirectoryBucket;
import static com.example.s3.util.S3DirectoryBucketUtils.createS3Client;
import static com.example.s3.util.S3DirectoryBucketUtils.deleteDirectoryBucket;

    /**
     * Retrieves the encryption configuration for an S3 directory bucket.
     *
     * @param s3Client   The S3 client used to interact with S3
     * @param bucketName The name of the directory bucket
     * @return The type of server-side encryption applied to the bucket (e.g.,
     *         AES256, aws:kms)
     */
    public static String getDirectoryBucketEncryption(S3Client s3Client, String bucketName) {
        try {
            // Create a GetBucketEncryptionRequest
            GetBucketEncryptionRequest getRequest = GetBucketEncryptionRequest.builder()
                    .bucket(bucketName)
                    .build();

            // Retrieve the bucket encryption configuration
            GetBucketEncryptionResponse response = s3Client.getBucketEncryption(getRequest);
            ServerSideEncryptionRule rule = response.serverSideEncryptionConfiguration().rules().get(0);

            String encryptionType = rule.applyServerSideEncryptionByDefault().sseAlgorithmAsString();
            logger.info("Bucket encryption algorithm: {}", encryptionType);
            logger.info("KMS Customer Managed Key ID: {}", rule.applyServerSideEncryptionByDefault().kmsMasterKeyID());
            logger.info("Bucket Key Enabled: {}", rule.bucketKeyEnabled());

            return encryptionType;
        } catch (S3Exception e) {
            logger.error("Failed to get bucket encryption: {} - Error code: {}", e.awsErrorDetails().errorMessage(),
                    e.awsErrorDetails().errorCode(), e);
            throw e;
        }
    }