index.md

Tw-Spyql documentation

A professional spy for your JDBC data source. It's a javax.sql.DataSource wrapper, which provides multiple event hooks.

It doesn't provide any implementation out of the box. Users are expected to provide the implementation. However, there is an example project tw-spyql-simple-logger which logs certain events.

Usage

If you are using a Spring Boot service then the following steps apply:

1. Add a dependency com.transferwise.common:tw-spyql-starter. It will automatically wrap your data sources, exposed as beans, with SpyqlDataSource.
2. Add a Spring configuration which gets all the DataSource beans, unwrap the SpySqlDataSource and add your custom SpyqlDataSourceListener objects. Example snippet:

   @Configuration
   public class ExampleBeanPostProcessor implements BeanPostProcessor {
   
       @Override
       public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
         return bean;
       }
   
       @Override
       public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
         if (!(bean instanceof DataSource)) {
           return bean;
         }
         SpyqlDataSource dataSource = ((DataSource) bean).unwrap(SpyqlDataSource.class);
         dataSource.addListener(new MySpyqlDataSourceListener());
       }
   }
   

Features

Datasource that is wrapped into SpyqlDataSource allows you to add listeners to different events related to datasources and execute actions during those events.

For example, you can execute an action when a statement is executed, transaction is commited or rolled back. Reference SpyqlDataSourceListener and SpyqlConnectionListener interfaces to see which event listeners are possible.