CAM-11819 improve ProcessEngineException message

[SolarBilling]

Currently when a task listener throws an exception, Camunda displays a message something like:

"ENGINE-03051 There was an exception while invoking the TaskListener. Message: 'ENGINE-07002 Exception while notifying process application task listener."

This gives the user no clue what went wrong because it throws away the message from the original exception and it includes duplicated information which is meaningless to the end user.

This change request prevents the duplicated information and includes the message from the original exception in the new exception, so that it may display something meaningful to the user.

[tasso94]

Hi @SolarBilling,

Thank you for your contribution.

I will look into it and come back to you with feedback – next week at the latest.

Stay tuned!

Best,
Tassilo

[tasso94]

Hi @SolarBilling,

Thank you for your contribution.

I'm not sure about the following changes:

    if (e instanceof ProcessEngineException) {
      return (ProcessEngineException)e;
    }

If I understand your use case correctly, adding the exception message of the initially thrown exception to the new ProcessEngineException should be enough, right?

Best,
Tassilo

[SolarBilling]

Hi @SolarBilling,

Thank you for your contribution.

I'm not sure about the following changes:

    if (e instanceof ProcessEngineException) {
      return (ProcessEngineException)e;
    }

If I understand your use case correctly, adding the exception message of the initially thrown exception to the new ProcessEngineException should be enough, right?

Best,
Tassilo

You are correct that adding the exception message of the initially thrown exception to the new ProcessEngineException is the most important part of the change request and would be a big improvement by itself.
If you just did that, then if the error message is "invalid email address" for example, it would display:

ENGINE-03051 There was an exception while invoking the TaskListener. Message: 'ENGINE-07002 Exception while notifying process application task listener: invalid email address

That's a lot better than just "ENGINE-03051 There was an exception while invoking the TaskListener. Message: 'ENGINE-07002 Exception while notifying process application task listener." which gives the user no clue what went wrong but it's still ugly and hard for users to read.
With the addition of the change above, the error message displayed becomes "invalid email address" if the listener throws a ProcessEngineException or
"'ENGINE-07002 Exception while notifying process application task listener: invalid email address" if the listener throws some other exception, which is more succinct as it doesn't repeat itself - "There was an exception while invoking the TaskListener" means the same thing as "Exception while notifying process application task listener".

[tasso94]

Hi @SolarBilling,

Thank you for the clarification.

I would prefer the nested messages since it makes transparent to the user where the exception was thrown initially but also indicates that it happened in the context of a process application. This also helps third parties (e.g. in our forums) by just looking at the logs to get a better understanding of the used architecture.

Would you mind removing the if branches?

Best,
Tassilo

[SolarBilling]

I have made the change you requested.

[tasso94]

Hi @SolarBilling,

sorry for my late response.
I'll recheck your changes today or tomorrow at the latest.

Stay tuned!

Best,
Tassilo

[tasso94]

Hi @SolarBilling,

Thank you again for your contribution.

I just merged your changes with the master branch.

Best,
Tassilo