I've checked the questions on the site about Resilience4J, but have not had any luck with their answers. I'm trying to implement @CircuitBreaker annotation from Resilience4J in my Spring Boot 2.x project. The circuit breaker is implemented around a pretty straightforward function. However, when I supply a bad URL, the circuit is not opening, no matter how many times I send the request. I've gone so far as to extract everything into a standalone application and run it 100 times and observe it just endlessly failing. Any idea what I'm doing wrong?
@CircuitBreaker(name = "backendA")
@Component
public class ResilientClient {
private HttpClient httpClient;
private static final Logger log = LoggerFactory.getLogger(ResilientClient.class);
public ResilientClient() {
httpClient = HttpClient.newBuilder().build();
}
@Bulkhead(name = "backendA")
public String processPostRequest(String body, String[] headers, String url) {
HttpResponse<String> response = null;
HttpRequest request = HttpRequest.newBuilder()
.uri(URI.create(url))
.POST(HttpRequest.BodyPublishers.ofString(body))
.headers(headers)
.build();
try {
response = httpClient.send(request, HttpResponse.BodyHandlers.ofString());
} catch (IOException e) {
throw new HttpServerErrorException(HttpStatus.INTERNAL_SERVER_ERROR, "This is a remote exception");
} catch (InterruptedException e) {
e.printStackTrace();
log.error("Interrupted Exception: " + e.getLocalizedMessage(), e);
}
return response != null ? response.body() : null;
};
// None of these functions ever get invoked
private String fallback(Throwable e){
log.info("generic throwable caught");
return "generic result";
}
private String fallback(String param1, String[] headers, String url, Throwable e) {
log.info("Fallback method invoked for Throwable: " + param1);
return null;
}
private String fallback(String param1, String[] headers, String url, ConnectException e) {
log.info("Fallback method invoked for ConnectException: " + param1);
return null;
}
}
The config file is taken directly from the Github example
resilience4j.circuitbreaker:
configs:
default:
registerHealthIndicator: false
slidingWindowSize: 10
minimumNumberOfCalls: 5
permittedNumberOfCallsInHalfOpenState: 3
automaticTransitionFromOpenToHalfOpenEnabled: true
waitDurationInOpenState: 2s
failureRateThreshold: 50
eventConsumerBufferSize: 10
recordExceptions:
- org.springframework.web.client.HttpServerErrorException
- java.io.IOException
ignoreExceptions:
- io.github.robwin.exception.BusinessException
shared:
registerHealthIndicator: true
slidingWindowSize: 100
permittedNumberOfCallsInHalfOpenState: 30
waitDurationInOpenState: 1s
failureRateThreshold: 50
eventConsumerBufferSize: 10
ignoreExceptions:
- io.github.robwin.exception.BusinessException
instances:
backendA:
baseConfig: default
backendB:
registerHealthIndicator: true
slidingWindowSize: 10
minimumNumberOfCalls: 10
permittedNumberOfCallsInHalfOpenState: 3
waitDurationInOpenState: 1s
failureRateThreshold: 50
eventConsumerBufferSize: 10
recordFailurePredicate: io.github.robwin.exception.RecordFailurePredicate
resilience4j.retry:
configs:
default:
maxRetryAttempts: 2
waitDuration: 100
retryExceptions:
- org.springframework.web.client.HttpServerErrorException
- java.io.IOException
ignoreExceptions:
- io.github.robwin.exception.BusinessException
instances:
backendA:
maxRetryAttempts: 3
backendB:
maxRetryAttempts: 3
resilience4j.bulkhead:
configs:
default:
maxConcurrentCalls: 100
instances:
backendA:
maxConcurrentCalls: 10
backendB:
maxWaitDuration: 10ms
maxConcurrentCalls: 20
resilience4j.thread-pool-bulkhead:
configs:
default:
maxThreadPoolSize: 4
coreThreadPoolSize: 2
queueCapacity: 2
instances:
backendA:
baseConfig: default
backendB:
maxThreadPoolSize: 1
coreThreadPoolSize: 1
queueCapacity: 1
resilience4j.ratelimiter:
configs:
default:
registerHealthIndicator: false
limitForPeriod: 10
limitRefreshPeriod: 1s
timeoutDuration: 0
eventConsumerBufferSize: 100
instances:
backendA:
baseConfig: default
backendB:
limitForPeriod: 6
limitRefreshPeriod: 500ms
timeoutDuration: 3s
Code to try testing it
SpringBootApplication
public class CircuitsApplication {
private static final Logger logger = LoggerFactory.getLogger(CircuitsApplication.class);
static ResilientClient resilientClient = new ResilientClient();
public static void main(String[] args) {
//SpringApplication.run(CircuitsApplication.class, args);
for (int i = 0; i < 100; i++){
try {
String body = "body content";
String[] headers = new String[]{"header", "value"};
String url = "http://a.bad.url";
String result = resilientClient.processPostRequest(body, headers, url);
logger.info(result);
} catch (Exception ex){
logger.info("Error caught in main loop");
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}
I've tried adding the Circuitbreaker annotation to the method itself. I've tried creating a supplier and decorating it. I've tried adding the Bulkhead, removing the Bulkhead. I've tried adding additional fallback methods with different signatures. I've tried with and without @Component.
All I end up getting in my logs is this 100 times:
14:33:10.348 [main] INFO c.t.circuits.CircuitsApplication - Error caught in main loop
I'm not sure what I'm missing. Any help would be greatly appreciated.
I don't think this will work. Firstly, you are instantiating your ResilientClient as new ResilientClient(). You have to use the created Bean not instantiate it yourselves. The @CircuitBreaker annotation uses spring-aop. So you will have to run your class as SpringBootApplicaiton.
Secondly, you are only recording HttpServerErrorException and IOException as failures. So circuit breaker treats all other exceptions (except the ones mentioned above and their children) as success.