How to trigger the Camunda Retry mechanism in case of a service call

Camunda 7 Topics Discussion & Questions
1

Hi,

I was reading the latest book of Bernd : Practical Process Automation (great book btw)

And there I spotted the following workflow

Camunda_exception
Camunda_exception1488×1116 39.9 KB

When I try it myself in my implementation that uses a Java Delegate the “Retry mechanism” only is activated when I throw an java exception, when I throw a BPMN_ERROR then the retry is not performed but the “Error Boundary Event” will directly consume the event and the “Error Cleanup Task” is triggered.

So what am I doing wrong in my setup, I would like to have to have that the java call (JavaDelegate) will retry 5 times with a timespan of 5 min and if then the exception remains the “Error Boundary Event” will trigger then “Error Cleanup”

2

You might query the current job and check the number of retires left. If it’s zero you throw a BpmnError.

1 Like
3

You can try a model like this

image

4

This one I was able to implement but it is one is one of the anti-patterns that is defined on the Camunda website as you putting technical error handling stuff in your business model

Camunda Best Practices - Operating Camunda

So this is what I wanted to avoid

5

ok then try this

https://docs.camunda.org/manual/7.10/user-guide/process-engine/the-job-executor/#retry-intervals

6

Hi @Jan_Casteels,

you can access the ExecutionEntity in your delegate code and get the remaining retries from there and finally throw a BpmnError like here:

  public void execute(DelegateExecution execution) throws Exception {
    String content = (String) execution.getVariable("content");
    ExecutionEntity ee = (ExecutionEntity) execution; 
    try {
      publishTweet(content);
    } catch (TwitterException e) {
      if (ee.getJobs().get(0).getRetries() == 0 && e.getErrorCode() == 187) {
        throw new BpmnError("tweetDoppelt", e.getLocalizedMessage());
      } else {
        throw e;
      }
    }
  }

Hope this helps, Ingo

3 Likes
7

Hello @Ingo_Richtsmeier ,

I didn’t know it’s possible this way, thank you for the hint. BTW: Why is the check for the code 187 needed?

I’d do it via a job query (and search by the activity id). But the idea is the same.

1 Like