[Improvement] possible ClassCastException in JdbcCatalogMetricsSource

What would you like to be improved?

JdbcCatalogMetricsSource.registerDatasourceMetrics(DataSource dataSource) currently performs an unconditional cast to BasicDataSource. This makes the method unsafe for any valid DataSource implementation, and it can fail at runtime with a ClassCastException. The improvement needed is to make datasource metric registration robust across non-DBCP DataSource instances, or at minimum fail safely.

How should we improve?

Update registerDatasourceMetrics to handle non-BasicDataSource inputs safely, rather than casting directly.

Here's a unit test to show the issue:

public class TestJdbcCatalogMetricsSource {

  @Test
  public void testRegisterDatasourceMetricsWithNonBasicDataSource() {
    JdbcCatalogMetricsSource source = new JdbcCatalogMetricsSource("metalake", "catalog");

    DataSource nonBasicDataSource =
        new DataSource() {
          @Override
          public Connection getConnection() {
            return null;
          }

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

          @Override
          public PrintWriter getLogWriter() {
            return null;
          }

          @Override
          public void setLogWriter(PrintWriter out) {}

          @Override
          public void setLoginTimeout(int seconds) {}

          @Override
          public int getLoginTimeout() {
            return 0;
          }

          @Override
          public Logger getParentLogger() throws SQLFeatureNotSupportedException {
            return Logger.getGlobal();
          }

          @Override
          public <T> T unwrap(Class<T> iface) throws SQLException {
            throw new SQLException("Not a wrapper");
          }

          @Override
          public boolean isWrapperFor(Class<?> iface) {
            return false;
          }
        };

    Assertions.assertDoesNotThrow(() -> source.registerDatasourceMetrics(nonBasicDataSource));
  }
}