Complete the UserTask or send a message, what is better?

Camunda 8 Topics Discussion & Questions
1

Hello,

I’m wondering what is best practice here.

Idea 1:

  • if a usertask is reached, use @ZeebeWorker(type = "io.camunda.zeebe:userTask") to find (job.getElementId()) the task and get the id
  • save the id in a database
  • if the task is done, due to a click on a frontend button, use the id in the database to complete (zeebeClient.newCompleteCommand()) the usertask
  • proceed with the rest of the process

Idea 2:

  • create a database with tasks, each task has a unique id
  • send a message if the frontend button is clicked zeebeClient.newPublishMessageCommand().messageName("Message_Form_Done").correlationKey(id)
  • delete the task from the database
  • proceed with the rest of the process

Any other ideas how to handle this?

Thanks for you ideas and tips in advanced.

Cheers.

2

Hi,

I see two parts to your question.

Modeling
First, it’s about how to model the process and user’s interacting with it. This is a design decision. If the user is a process participant, who is part of the company executing the process - I’d prefer the user task. It clearly shows the responsibilities.
If your user is an external party, e.g., a customer, I’d choose a message.

Implementation
The implementation also depends on the Camunda Version you’re using. In the enterprise version, you can also access the Tasklist API to complete your user tasks.

A fourth alternative (if you’re using self-managed Camunda 8) is a custom exporter that stores and maintains your user task IDs.

1 Like
3

Hello Stephan,

Thanks for you answer, some more details from my side.
I’m using a self-managed Camunda 8 Version. Without an enterprise license.

Screenshot from 2022-08-22 17-08-47
Screenshot from 2022-08-22 17-08-47760×445 17.7 KB

The Fill Form task is the culprit momentarily.
It feels not right to complete the task in a Java method by just completing(zeebeClient.newCompleteCommand()) it.
From my point of view, in that case the API takes over control and overrules the Camunda process while with the message the process control stays on Camunda side.

Camunda should always be in control and only influenced by messages. Am I wrong here?
This point confuses me since days :thinking:

4

Hi,

The zeebe client only sends messages. However, these messages are on a technical abstraction layer, while BPMN messages are on a conceptual level. The Zeebe client remains in full-control, as messages can be rejected/ignored. So using this functionality is fine.

It’s also completely fine to, e.g., write your own exporter to implement your custom tasklist-API. This is how Camunda 8’s own components are implemented. An exporter, however, should be as lightweight as possible and site effects must not affect the engine.

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