Accessing AWS RDS using IAM Authentication and Spring JDBC (DataSource and JdbcTemplace)

Question

I am not able to figure out how to implement this. Any help and/or pointers will be greatly appreciated.

Currently, my Java/Spring application backend is deployed on EC2 and accessing MySQL on RDS successfully using the regular Spring JDBC setup. That is, storing database info in application.properties and configuring DataSource and JdbcTemplate in @Configuration class. Everything works fine.

Now, I need to access MySQL on RDS securely. RDS instance has IAM Authentication enabled. I have also successfully created IAM role and applied inline policy. Then, following the AWS RDS documentation and Java example on this link, I am able to access the database from a standalone Java class successfully using Authentication Token and the user I created instead of regular db username and password. This standalone Java class is dealing with "Connection" object directly.

The place I am stuck is how I translate this to Spring JDBC configuration. That is, setting up DataSource and JdbcTemplate beans for this in my @Configuration class.

What would be a correct/right approach to implement this?

----- EDIT - Start -----

I am trying to implement this as a library that can be used for multiple projects. That is, it will be used as a JAR and declared as a dependency in a project's POM file. This library is going to include configurable AWS Services like this RDS access using general DB username and password, RDS access using IAM Authentication, KMS (CMK/data keys) for data encryption, etc.

Idea is to use this library on any web/app server depending on the project.

Hope this clarifies my need more.

----- EDIT - End -----

DataSource internally has getConnection() so I can basically create my own DataSource implementation to achieve what I want. But is this a good approach?

Something like:

public class MyDataSource implements DataSource {
    @Override
    public Connection getConnection() throws SQLException {
        Connection conn = null;
        // get a connection using IAM Authentication Token for accessing AWS RDS, etc. as in the AWS docs
        return conn;
    }

    @Override
    public Connection getConnection(String username, String password) throws SQLException {
        return getConnection();
    }

    //other methods
} 

Answer 1

You can use the following snippet as a replacement for the default connection-pool provided by SpringBoot/Tomcat. It will refresh the token password every 10 minutes, since the token is valid for 15 minutes. Also, it assumes the region can be extracted from the DNS hostname. If this is not the case, you'll need to specify the region to use.

public class RdsIamAuthDataSource extends org.apache.tomcat.jdbc.pool.DataSource {

private static final Logger LOG = LoggerFactory.getLogger(RdsIamAuthDataSource.class);

/**
 * The Java KeyStore (JKS) file that contains the Amazon root CAs
 */
public static final String RDS_CACERTS = "/rds-cacerts";
/**
 * Password for the ca-certs file.
 */
public static final String PASSWORD = "changeit";
public static final int DEFAULT_PORT = 3306;

@Override
public ConnectionPool createPool() throws SQLException {
    return pool != null ? pool : createPoolImpl();
}

protected synchronized ConnectionPool createPoolImpl() throws SQLException {
    return pool = new RdsIamAuthConnectionPool(poolProperties);
}

public static class RdsIamAuthConnectionPool extends ConnectionPool implements Runnable {

    private RdsIamAuthTokenGenerator rdsIamAuthTokenGenerator;
    private String host;
    private String region;
    private int port;
    private String username;
    private Thread tokenThread;

    public RdsIamAuthConnectionPool(PoolConfiguration prop) throws SQLException {
        super(prop);
    }

    @Override
    protected void init(PoolConfiguration prop) throws SQLException {
        try {
            URI uri = new URI(prop.getUrl().substring(5));
            this.host = uri.getHost();
            this.port = uri.getPort();
            if (this.port < 0) {
                this.port = DEFAULT_PORT;
            }
            this.region = StringUtils.split(this.host,'.')[2]; // extract region from rds hostname
            this.username = prop.getUsername();
            this.rdsIamAuthTokenGenerator = RdsIamAuthTokenGenerator.builder().credentials(new DefaultAWSCredentialsProviderChain()).region(this.region).build();
            updatePassword(prop);
            final Properties props = prop.getDbProperties();
            props.setProperty("useSSL","true");
            props.setProperty("requireSSL","true");
            props.setProperty("trustCertificateKeyStoreUrl",getClass().getResource(RDS_CACERTS).toString());
            props.setProperty("trustCertificateKeyStorePassword", PASSWORD);
            super.init(prop);
            this.tokenThread = new Thread(this, "RdsIamAuthDataSourceTokenThread");
            this.tokenThread.setDaemon(true);
            this.tokenThread.start();
        } catch (URISyntaxException e) {
            throw new RuntimeException(e.getMessage());
        }
    }

    @Override
    public void run() {
        try {
            while (this.tokenThread != null) {
                Thread.sleep(10 * 60 * 1000); // wait for 10 minutes, then recreate the token
                updatePassword(getPoolProperties());
            }
        } catch (InterruptedException e) {
            LOG.debug("Background token thread interrupted");
        }
    }

    @Override
    protected void close(boolean force) {
        super.close(force);
        Thread t = tokenThread;
        tokenThread = null;
        if (t != null) {
            t.interrupt();
        }
    }

    private void updatePassword(PoolConfiguration props) {
        String token = rdsIamAuthTokenGenerator.getAuthToken(GetIamAuthTokenRequest.builder().hostname(host).port(port).userName(this.username).build());
        LOG.debug("Updated IAM token for connection pool");
        props.setPassword(token);
    }
}
}

Please note that you'll need to import Amazon's root/intermediate certificates to establish a trusted connection. The example code above assumes that the certificates have been imported into a file called 'rds-cacert' and is available on the classpath. Alternatively, you can also import them into the JVM 'cacerts' file.

To use this data-source, you can use the following properties for Spring:

datasource:
  url: jdbc:mysql://dbhost.xyz123abc.us-east-1.rds.amazonaws.com/dbname
  username: iam_app_user
  driver-class-name: com.mysql.cj.jdbc.Driver
  type: com.mydomain.jdbc.RdsIamAuthDataSource

Using Spring Java config:

@Bean public DataSource dataSource() { 
    PoolConfiguration props = new PoolProperties(); 
    props.setUrl("jdbc:mysql://dbname.abc123xyz.us-east-1.rds.amazonaws.com/dbschema"); 
    props.setUsername("iam_dbuser_app"); 
    props.setDriverClassName("com.mysql.jdbc.Driver"); 
    return new RdsIamAuthDataSource(props); 
}