How to: Author and manage Dapr Workflow with Spring Boot

Following the same approach that we used for Spring Data and Spring Messaging, the dapr-spring-boot-starter brings Dapr Workflow integration for Spring Boot users.

With Dapr Workflows you define complex orchestrations (workflows) in Java code. The Dapr Spring Boot Starter makes your development easier by managing Workflows and WorkflowActivitys as Spring Beans.

In order to enable the automatic bean discovery you annotate your @SpringBootApplication with the @EnableDaprWorkflows annotation:

@SpringBootApplication
@EnableDaprWorkflows
public class MySpringBootApplication {
  ...
}

By adding this annotation, all the Workflows and WorkflowActivitys beans are automatically discovered by Spring and registered to the workflow engine.

Creating Workflows and Activities

Inside your Spring Boot application you can define as many workflows as you want. You do that by creating new implementations of the Workflow interface.

@Component
public class MyWorkflow implements Workflow {
    
    @Override
    public WorkflowStub create() {
      return ctx -> {
         <WORKFLOW LOGIC>
      };
    }

}

From inside your workflow definitions, you can perform service to service interactions, schedule timers or receive external events.

By having all WorkflowActivitys as managed beans you can use the Spring @Autowired mechanism to inject any bean that the workflow activity might need to implement its functionality. For example the @RestTemplate:

@Component
public class MyWorkflowActivity implements WorkflowActivity {

  @Autowired
  private RestTemplate restTemplate;

Creating and interacting with Workflows

To create and interact with Workflow instances you use the DaprWorkflowClient that you can also @Autowired.

@Autowired
private DaprWorkflowClient daprWorkflowClient;

Applications can now schedule new workflow instances and raise events.

String instanceId = daprWorkflowClient.scheduleNewWorkflow(MyWorkflow.class, payload);

and

daprWorkflowClient.raiseEvent(instanceId, "MyEvenet", event);

Check a full example here

Next Steps & Resources

Check the blog post from Baeldung covering Dapr Workflows and Dapr Pubsub with a full working example.

Check the Dapr Workflow documentation for more information about how to work with Dapr Workflows.