Howto change the Retry Cycle Time value without process re-deployment

[hba...@gmail.com]

Hello,
is it possible to change the Retry Cycle Time value of Service Tasks without the need to redeploy the process. Maybe in combination with Spring Properties?

Many regards,
Hermann

[Daniel Meyer]

Hi Hermann,

you can change it locally (on a single cluster node) using internal API (by modifying the activity in the ProcessDefinition Graph).

You need to write a custom command, get your hands on the DeploymentCache, get the processDefinition form the Deployment Cache, 

find the ActivityImpl corresponding to your service task and modify the property

activity.setProperty(FoxFailedJobParseListener.FOX_FAILED_JOB_CONFIGURATION, someNewValue);

To sum up: no, this is not really possible. 

Maybe you can give us some insight on your usecase? Why do you want to modify it? 

Cheers,

Daniel Meyer

[hba...@gmail.com]

Hello Daniel,
thank's for your answer and your question. Here are some additional background informations:

* we use the camunda jars inside of a Spring, RESTEasy web service
* application server is tomcat
* our new process contains 5 asynchronous ServiceTasks, each send a request to a backend service
* in generall our backend services are very fast, high available and our customers should get the process output as fast as possible (< 1 sec.) – we use the asynchronous feature (with retries) so that each service call is made and to handle the rare technical error cases
* our IT staff (without special BPMN/camunda know how) is always available to resolve critical situations. Softwaredeveloper are only on working days between 9.00 and 17.00 available
* our IT needs a simple way to controll the number of requests. This is necessary to reduce the number of service requests in critical heavy load situations

I'm now searching for a good solution to fulfill our IT requirement. My first thougths (without knowing how much work is involved for the realization) are:
* maby we could make the number of job executor threads configurable?
* maby we could make the job execution time interval configurable?
* maby we could use the Retry Time Cycle (initial configuration: R2160/PT2M) and make the value for each service configurable for our IT? After max. 3 days a software developer /operations manager could restart the process manual via camunda REST API.

I am looking forward about your feedback. Also since i am not very happy with my solutions listed above.

Many regards,
Hermann

[Daniel Meyer]

Hi Hermann,

thanks for the clarification. Maybe the solution would be to support expression language for configuring the Retry Time Cycle. This would allow you to resolve the retry time cycle using a Spring / CDI / EJB bean or something like that which could read it from a configuration source.

WDYT?

Cheers,

Daniel Meyer

[hba...@gmail.com]

Hallo Daniel,
that sounds good for me :-)

Currently we use the Spring property placeholder to load the engine configuration properties:

<context:property-placeholder location="classpath*:config/application.properties" />

<context:component-scan base-package="org.camunda.bpm.example.loanapproval" />

We could add the Retry Time Cycle values to the existing property file, e.g.:

calculateInterestServiceTask.retryTimeCycle=R4/PT1M

As far as i know the property placeholder could inject the property values only at application context startup time. If your proposed solution is similar to the already existing Spring Bean – Service Task expression language solution (e.g. implemendet in ServiceTaskDelegateExpressionActivityBehavior – execute(...) - Object delegate = expression.getValue(execution);), it's possible to add a property holder bean in the application, e.g.:

@Named
public class RetryTimeCyclePropertyHolder {

private final String calculateInterestServiceTaskValue;

@Inject
public RetryTimeCyclePropertyHolder(
@Value("${calculateInterestServiceTask.retryTimeCycle}") final String calculateInterestServiceTaskValue) {
this.calculateInterestServiceTaskValue = calculateInterestServiceTaskValue;
}

public String getCalculateInterestServiceTaskValue() {
return calculateInterestServiceTaskValue;
}
}

If you're interested, i could try to implement this feature with a little help from you in a camunda branch. Or do you think it is better to implement a custom JobRetryCmd class?

Many regards,
Hermann

[hba...@gmail.com]

Hello,
it is also possible to use:

<util:properties id="camundaSettings" location="classpath:config/camunda.properties" />

which creates a java.util.properties bean containing all the properties.

The property values could be read e.g. via:

ExpressionParser parser = new SpelExpressionParser();
StandardEvaluationContext context = new StandardEvaluationContext();
context.setBeanResolver(new BeanFactoryResolver(applicationContext));

Expression expression =
parser.parseExpression("@camundaSettings['calculateInterestServiceTask.retryTimeCycle']");
final String value = expression.getValue(context, String.class);

Many regards,
Hermann

[Halil]

Hi Daniel,

is this feature already implemented.

We have a similar use case as described above by Hermann and want to modify the failedJobRetryTimeCycle dynamically.

Thanks beforehand.

Best regards

Halil