Unable to customize the password when creating the connection

[mnbattaglia]

We are using AWS RDS IAM to get a temporary access token that must be used as the connection password. This is valid only for 15 min, so we must obtain another token when creating a new connection. By using a connection pool, the solution is to set a max life time with a less than 15 min duration (eg: 14 min) and connection should be re-created after that. There are several solutions in the web with JDBC implementations, where you can implement your own pool (eg: extending Hikari) and then overwrite the getPassword function, calling the proper AWS method to get the token at that moment. I'm trying a similar approach with r2dbc, but cannot get to hook while creating the connection. I'm using spring boot. Tried:

• ConnectionFactoryOptionsBuilderCustomizer: this is only applied when creating the pool, so, doesn't work
• Creating my own ConnectionPool bean, doing the same as ConnectionFactoryConfigurations.PoolConfiguration. In that case, the pool uses my own ConnectionFactory as I was expecting the create() method to be called every time a connection is created. But no! Somehow it doesn't get called.

In summary, what I'm trying to achieve is to set the password dynamically when connection is being created in the pool. Any suggestions? Thanks in advance

[mnbattaglia]

Closing this one as it was properly answered in an r2dbc-postgres issue

The following example provided by @mp911de works like a charm:

ConnectionFactoryOptions options = ConnectionFactoryOptions.parse("r2dbc:postgresql://host/database");

ConnectionFactory connectionFactoryStub = ConnectionFactories.get(options);

Mono<? extends Connection> connectionPublisher = Mono.defer(() -> {

    ConnectionFactoryOptions optionsToUse = options.mutate()
        .option(ConnectionFactoryOptions.USER, "…") // provide a new username each time we see a connect request
        .option(ConnectionFactoryOptions.PASSWORD, "…") // provide a new password each time we see a connect request
        .build();

    return Mono.from(ConnectionFactories.get(optionsToUse).create());
});

ConnectionFactory myCustomConnectionFactory = new ConnectionFactory() {

    @Override
    public Publisher<? extends Connection> create() {
        return connectionPublisher;
    }

    @Override
    public ConnectionFactoryMetadata getMetadata() {
        return connectionFactoryStub.getMetadata();
    }
};

ConnectionPoolConfiguration poolConfiguration = ConnectionPoolConfiguration.builder().connectionFactory(myCustomConnectionFactory).build();
ConnectionPool pool = new ConnectionPool(poolConfiguration);
// …

My mistake was that I was not deferring the create() delegate