Can we handle nested exceptions using spring retry?

Question

I am learning Spring Retry and have the following question on its capability:

I have a function which connects to a third party application API. It is anticipated that this can throw different exceptions like Timeout or IO exceptions. I was trying to see if spring's retry template will be able to handle such nested exceptions on "each" occurence. For example, when we set the maxAttempts to 3 for individual exceptions, then it should attempt 3 times at each occurence even if it is within a retry. for example, on attempt 1 - Exception 1 occured and next attempt (attempt 2) it was successful, but now exception 2 happens, based on the retryPolicy it should initiate attempt 1 for Exception 2.

Is this possible?

Based on a small POC, I see that it was trying only 3 times even when both types were thrown:

Controller Class with retryTemplate:

         retryTemplate.execute(new RetryCallback<Customer, Exception>(){
             @Override
                public Customer doWithRetry(RetryContext arg0) throws Exception{
                System.out.println("count #"+arg0.getRetryCount());
                if(arg0.getRetryCount()>0) {
                    System.out.println("throwable getClass Canonical Name "+arg0.getLastThrowable().getClass().getCanonicalName());
                }

                return  customerService.getCustomerDetails(choice);
             }});

Exception Simulation class:

Random r = new Random();

            int i = r.nextInt();
            i+=1;

            System.out.println("value of i "+i);
            if(i%2==0) {
                throw new Exception1();
            }
            else {
                throw new Exception2();
            }

Here are the logs:

count #0
in getCustomerDetails
value of i -1050226395
count #1
throwable getClass Canonical Name Exception1
in getCustomerDetails
value of i 824190506
count #2
throwable getClass Canonical Name Exception2
in getCustomerDetails
value of i 1210506150
Exception1

Expected result: Attempt for 3 times for each occurence of the exception

Actual Result: It is attempting only for total of 3 .

Below is my RetryPolicy: ExceptionClassifierRetryPolicy has the policyMap for both type of exceptions

public RetryTemplate retryTemplate() {

    RetryTemplate retryTemplate = new RetryTemplate();
    final SimpleRetryPolicy simpleRetryPolicy = new SimpleRetryPolicy();
    simpleRetryPolicy.setMaxAttempts(3);
    FixedBackOffPolicy backOffPolicy = new FixedBackOffPolicy();
    backOffPolicy.setBackOffPeriod(1500);
    final Map<Class<? extends Throwable>, RetryPolicy> policyMap = new HashMap<>();
    policyMap.put(Exception1.class, simpleRetryPolicy);
    policyMap.put(Exception2.class, simpleRetryPolicy);
    final ExceptionClassifierRetryPolicy retryPolicy = new ExceptionClassifierRetryPolicy();
    retryPolicy.setPolicyMap(policyMap);
    retryTemplate.setBackOffPolicy(backOffPolicy);
    retryTemplate.setRetryPolicy(retryPolicy);
    return retryTemplate;
}

Questions:

Can Spring retry be used for this scenario?
If so, what is required to be changed in the above implementation?

Please guide.

Wim Deblauwe · Accepted Answer · 2020-01-07 07:26:14Z

2

You can use ExceptionClassifierRetryPolicy, but be sure to assign different instances of SimpleRetryPolicy for each exception type:

ExceptionClassifierRetryPolicy retryPolicy = new ExceptionClassifierRetryPolicy();
Map<Class<? extends Throwable>, RetryPolicy> policyMap = new HashMap<>();

policyMap.put(Exception1.class, new SimpleRetryPolicy(3));
policyMap.put(Exception2.class, new SimpleRetryPolicy(3));

retryPolicy.setPolicyMap(policyMap);
retryTemplate.setRetryPolicy(retryPolicy);

answered Jan 7, 2020 at 7:26

Wim Deblauwe

27.2k23 gold badges157 silver badges234 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Can we handle nested exceptions using spring retry?

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related