Calling a service which takes long time to finish from camunda java delegate

Question

I need to implement camunda bpmn where 1 of my task is a java delegate task which calls an api. now the api what it calls is an async api, because of which the bpmn flow moves to next task after calling the async api but i want is that after calling the api the flow shud stop and then some call back happens through some api to camunda server(hosted as spring boot app). what would be the best way to achieve the above scenario.

Answer 1

You can do this to halt the execution for the specified amount of time.

This will halt the execution for the response

Answer 2

Options for asynchronous communication are

1. A send task/event follow by receive task/event

https://docs.camunda.org/manual/latest/reference/bpmn20/tasks/send-task/ https://docs.camunda.org/manual/latest/reference/bpmn20/tasks/receive-task/ https://docs.camunda.org/manual/latest/reference/bpmn20/events/message-events/

2. a service task of implementation type external

https://docs.camunda.org/manual/latest/user-guide/process-engine/external-tasks/

3. Advanced: Implement asynchronous service invocation using a Signallable Activity Behavior

https://github.com/camunda/camunda-bpm-examples/tree/master/servicetask/service-invocation-asynchronous

From this blog post, whcih provides a detailed explanation: https://blog.camunda.com/post/2013/11/bpmn-service-synchronous-asynchronous/