Bootstrap Steps

AuthGuard can run certain steps before starting the server, those are called "bootstrap steps". There are no restrictions on what those steps can do. For example, they can just log a message, connect to an external service, or create database indices.

Creating a Step#

All you need to do is to create a class which implements BootstrapStep interface, and your class will be discovered automatically.

public class CustomStep implements BootstrapStep {

    @Override
    public void run() {
        // add the logic of your step here
    }
}

Steps are initialized after configuration and all dynamic bindings are initialized, and just like other extensions, they can have access to their own configuration or inject some of the services. For example:

@Inject
public CustomStep(RolesService rolesService, @Named("custom") ConfigContext customStepConfig) {
    // do something with the service and the config
}

Implementation Guidelines#

While there are no restrictions what steps can do, there are certain guidelines that you need to be aware of

Independence#

Steps are completely independent and cannot be dependent on other steps. In other words, a step cannot accept another step in the constructor and the order of execution is not guaranteed either.

Idempotency#

Steps with side effects should be idempotent since they'll run every time AuthGuard is restarted.

Concurrency#

Unless necessary, steps should not return before all of their tasks are done. They should not schedule something in the background.

Failure#

Exceptions thrown by steps are logged and they will not prevent the server from starting. For fatal failures that should halt the server a step may just force the process to terminate. This will be replaced in the future with a halt signal that makes the application shut down gracefully.