This repository contains four modules:
naive-chaos-monkey: A custom Neo4j transaction listener that makes roughly half of all transaction failsdn-domain: A Spring Data Neo4j domain containing the usual movies and actors, with two repositories as data access objectssdn-with-resilience4j: A Spring Boot application with SDN and a service class that uses both repositories and has several interactions with the database. The service is made retryable with resilience4j.sdn-with-spring-retry: A Spring Boot application with SDN and a service class that uses both repositories and has several interactions with the database. The service is made retryable with spring-retry.
Both applications use the same domain, and the same service code. Both retry mechanism are ultimately based on an additional Aspect, hence both need to have higher precedence than the transactional interceptor.
The difference is that with spring-retry is that it will automatically unwrap the cause of any exception to look for the exceptions to retry on. resilience4j does not do that, so we need to use the SDN predicate to check if something should be retryable.
The way the "chaos monkey" makes transaction fail here will usually not happen as a retryable exception, as it makes things fail on commit. This will lead in SDN versions prior 7.2.11, 7.3.5 and 7.4.0-M2 to the retryable exception being swallowed. We improved this in in later versions, and this repository currently depends on a snapshot of 7.3.5, as we wanted to have an example that has reliable failure, so that one can see both retry mechanisms in action.