ConnectionFactory lacks a configuration option for closing the DataSource

[ppkarwasz]

While the ConnectionFactory connection source is the easiest way to implement custom connection sources, it currently does not provide an option to close the DataSource.

The closure of a DataSource created by ConnectionFactory must be done via external means.

[garydgregory]

I don't understand the problem. You allocate a resource, you close the resouce, like in PoolingDriverConnectionSourceTest.openAndClose(PoolingDriverConnectionSource).

Do we have an example or a test that leaks resources?

[ppkarwasz]

You can look at the HikariCP example I provided in #3128:

• I have a static LoggingDataSource.newInstance() method that creates a new DataSource each time it is called.
• The static method can be easily used together with FactoryMethodConnectionSource and the JDBC appender.
• When the Log4j configuration is stopped, however, DataSource.close() is not called and the connection pool does not deallocate its resources.

Of course the problem is not in Log4j Core itself and it could be solved by other means, but it would be useful to have a closeOnStop attribute that could be used together with the ConnectionFactory element:

<ConnectionFactory class="eu.copernik.spring.boot.LoggingDataSource"
                   method="newInstance"
                   closeOnStop="true"/>