使用IAM角色从Lambda连接到RDS MySql超时

IAM策略(与绑定到lambda函数的角色关联)

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "rds-db:connect"
            ],
            "Resource": [
                "arn:aws:rds-db:us-east-1:<account-id>:dbuser:<db-resource-id>/lambda"
            ]
        }
    ]
}

在数据库中创建的用户:

create user 'lambda' identified with AWSAuthenticationPlugin as 'RDS';
grant all privileges on cbr.* to 'lambda'@'%';
flush privileges;

private String generateAuthToken() {
    RdsIamAuthTokenGenerator generator = RdsIamAuthTokenGenerator.builder()
        .credentials(new DefaultAWSCredentialsProviderChain())
    .region(region)
    .build();

    String authToken = generator.getAuthToken(
    GetIamAuthTokenRequest.builder()
        .hostname(hostName)
        .port(Integer.parseInt(port))
        .userName(username)
        .build());

    return authToken;
}

public String test() throws SQLException {
    String currentTime = "Not Set";
    String jdbcUrl = "jdbc:mysql://" + hostName + ":" + port;
    String token = generateAuthToken();
    Connection conn = DriverManager.getConnection(jdbcUrl, username, generateAuthToken());

    Statement statement = conn.createStatement();
    ResultSet rs = statement.executeQuery("SELECT NOW()");

    if (rs.next()) {
        currentTime = rs.getString(1);
    }

    return currentTime;
}

我肯定我只是错过了一些东西