Preloading services

By default, a service will be instantiated when it's requested. In some cases you need to create an instance after booting the service container. For example a database connection or a background service that checks the connectivity.

To preload services you can use the @Preload annotation. This annotation is only available for singleton services. Example:

@Service()
@Preload()
class MyService {
  MyService() {
    print('Service was created');
  }
}

void main() {
  ServiceContainer container;
  container.boot(); // prints "Service was created" 
  container.resolve<MyService>(); // Nothing printed
}