Job Executor starts executing tasks BEFORE a spring boot app has startet

Camunda 7 Topics Discussion & Questions
1

Hi!

I noticed that Camunda tasks start to be executed BEFORE a spring boot application has completely started. I can see the corresponding log messages even before my CommanLineRunner beans are triggered.

Is this correct behavior? Can it be customized (e.g. postponed)?

Thank you!

2

Hi Vadim,

I’m not using Spring Boot but Wildfly with SessionBeans and an EjbProcessApplication.
Within the Camunda config Job Executor is disabled by default:
false

Within the PostDeploy of EjbProcessApplication the Job Executor is started then:

    @PostDeploy
    public void deployed( final ProcessEngine processEngine )
    {
...
        ProcessEngineConfigurationImpl processEngineConfigurationImpl = (ProcessEngineConfigurationImpl)processEngine.getProcessEngineConfiguration();
        JobExecutor jobExecutor = processEngineConfigurationImpl.getJobExecutor();
        jobExecutor.start();
    }

Regards, Frank

3

Thanks for your answer, Frank!
However, this is not applicable to a Spring Boot application since a Camunda spring boot starter is responsible for all the magic.

4

Hello @vadim.prudnikov ,

please find the spring boot configuration here:

https://docs.camunda.org/manual/7.15/user-guide/spring-boot-integration/configuration/

Maybe you could try to make the job executor deployment-aware.

Jonathan

5

I didn’t find out how to change the current behavior, however, I started using camunda.bpm.job-execution.core-pool-size and camunda.bpm.job-execution.max-pool-size properties, so Camunda is not allowed to consume too much resources even if the job executor starts too early.

6

Hi @vadim.prudnikov,

usually this is not a problem. When the job executor starts, all classes are loaded.

Why do you want to avoid it?

Hope this helps, Ingo

7

Hi @Ingo_Richtsmeier,

This is because of the following sequence:

  • Camunda job executor obtains too many resources (e.g. db connections from a connection pool)
  • Spring Framework runs CommandLineRunner beans that may also require the same resources
  • If CommandLineRunner fails with exception (because the resource cannot be acquired) then Spring framework treats the application as failed, so the whole app fails to start.

I assume that Camunda job executor can start doing its job after “Application started” has been written in the logs.

8

Hi @vadim.prudnikov,

the job executor is started here: camunda-bpm-platform/ProcessEngineImpl.java at master · camunda/camunda-bpm-platform · GitHub

As the JobExecutor itself is an abstract class, you can add your own implementation. But’s really deep in the heart of the process engine and I can’t assess if you can reach your desired goal with your own class.

Hope this helps, Ingo

9

Thanks for help, @Ingo_Richtsmeier
However, I think it’s all about Spring Boot configuration which is a bit complicated. As of now, the solution with thread pool properties seems to work for me.