MfaCredentailProvider.java

public class MfaCredentailProvider implements AWSCredentialsProvider {

		private DefaultAWSCredentialsProviderChain defaultChain = DefaultAWSCredentialsProviderChain.getInstance();

		private final String region;
		
		private AWSCredentials token;
		
		public MfaCredentailProvider(String region) {
			if(region == null) {
				this.region = new DefaultAwsRegionProviderChain().getRegion();
			} else {
				this.region = region;
			}
			
			this.refresh();
		}
		
		@Override
		public AWSCredentials getCredentials() {
			if(token != null) {
				return token;
			}  else {
				refresh();
			}
			return token;
		}

		@Override
		public void refresh() {
			try {
				token = getMfaCredentail();	
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		
		private AWSCredentials getMfaCredentail() {
			Optional<MFADevice> mfaDevice = getMFADevice();
			
			if(!mfaDevice.isPresent()) {
				return defaultChain.getCredentials();	
			}
			
			GetSessionTokenResult result = getSessionTokenResultByMfa(mfaDevice.get());
			Credentials cre = result.getCredentials();
			return new BasicSessionCredentials(cre.getAccessKeyId(), cre.getSecretAccessKey(), cre.getSessionToken());
		}
		
		private Optional<MFADevice> getMFADevice() {
		
			AmazonIdentityManagementClientBuilder builder = AmazonIdentityManagementClientBuilder.standard();
			builder.setRegion(this.region);

			AmazonIdentityManagement im = builder.build();
			ListMFADevicesResult result = im.listMFADevices();
			return result.getMFADevices().stream().findFirst();
		}
		
		private GetSessionTokenResult getSessionTokenResultByMfa(MFADevice mfaDevice) {
			
			System.out.println("MFADevice : " + mfaDevice.toString());
			System.out.println("please input mfa token : ");
			String token = "";
			
			try(Scanner scanner = new Scanner(System.in)) {
				token = scanner.nextLine().trim();	
			}
			
			GetSessionTokenRequest r = new GetSessionTokenRequest();
			r.setSerialNumber(mfaDevice.getSerialNumber());
			r.setTokenCode(token);

			AWSSecurityTokenService ss = AWSSecurityTokenServiceClientBuilder.standard()
					.withRegion(this.region)
					.build();
			
			log.info("AWS MFA success");
			return  ss.getSessionToken(r);
		}
	}