We will go through specific module(Resilience4j-Retry) from Resilience4j which is a fault tolerance library designed for Java8 and functional programming and it is lightweight library with minimal dependencies (mainly vavr)
When you retry , there are many cases for example :
- cross micro services communication for remote systems calls which most likely will need circuit breaker logic added as well
- if you have business or functional logic that need to get a consistent end state and most likely it is asynchronous Flow
Ok , what you need to do to start using resileience4j retry :
if you are using maven:
if you are using gradle :
What can be covered by the retry module of resilience4j :
- Synchronous retry and Asynchronous retry
- Rety on exceptions or response predicate which can be useful if you want to retry on specific response value not just thrown exceptions
- Back-off strategy for the retry configuration plus max retry attempts
- Ignoring set of exceptions to not retry on
- It has support for checked(exception handling added) and unchecked functions executions (ex Function , Supplier , Callable , Runnable..)
- it could be integrated with spring if needed.
Now showing examples of the mentioned features up:
How to configure the Asynchronous retry , full code for testing resilience4j retry on Github
For Synchronous calls , you have many options (Supplier , Callable , Function , plus Checked version of them, please check resilience4j retry APIs for more information) :
Example :
For more information , please check resilience4j Github and the code samples on GitHub as well .
In the next blogs I will cover spring and spring boot integration .
References :
