Trouble with Resilience4j Retry and "java.net.http.HttpClient" working together - resilience4j

Question

I'm trying to get a basic "httpclient" "httprequest" "httpresponse" working with Resilience4j Retry.
The verbatim code from : https://resilience4j.readme.io/docs/retry
RetryConfig config = RetryConfig.custom()
.maxAttempts(5)
.waitDuration(Duration.ofMillis(1000))
.retryOnResult(response -> response.getStatus() == 500)
.retryOnException(e -> e instanceof WebServiceException)
.retryExceptions(IOException.class, TimeoutException.class)
.ignoreExceptions(BusinessException.class, OtherBusinessException.class)
.build();
// Create a RetryRegistry with a custom global configuration
RetryRegistry registry = RetryRegistry.of(config);
// Get or create a Retry from the registry -
// Retry will be backed by the default config
Retry retryWithDefaultConfig = registry.retry("name1");
Note, their code above misses defining the generic "T", like this:
RetryConfig config = RetryConfig.<MyConcrete>custom()
and the verbatim code from : https://resilience4j.readme.io/docs/examples
Supplier<String> supplierWithResultAndExceptionHandler = SupplierUtils
.andThen(supplier, (result, exception) -> "Hello Recovery");
Supplier<HttpResponse> supplier = () -> httpClient.doRemoteCall();
Supplier<HttpResponse> supplierWithResultHandling = SupplierUtils.andThen(supplier, result -> {
if (result.getStatusCode() == 400) {
throw new ClientException();
} else if (result.getStatusCode() == 500) {
throw new ServerException();
}
return result;
});
HttpResponse httpResponse = circuitBreaker
.executeSupplier(supplierWithResultHandling);
======
So using those 2 "partials" , I've come up with this.
Note, I am using some "real" java.net.http.HttpClient and java.net.http.HttpResponse (from JDK11)
import io.github.resilience4j.core.SupplierUtils;
import io.github.resilience4j.retry.Retry;
import io.github.resilience4j.retry.RetryConfig;
import io.github.resilience4j.retry.RetryRegistry;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import javax.inject.Inject;
import java.io.IOException;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Duration;
import java.util.concurrent.TimeoutException;
import java.util.function.Supplier;
public final class ResilientHttpClient /* implements IResilientHttpClient */ {
private static Logger logger;
private final HttpClient httpClient;
#Inject
public ResilientHttpClient(final HttpClient httpClient) {
this(LoggerFactory
.getLogger(ResilientHttpClient.class), httpClient);
}
/**
* Constructor, which pre-populates the provider with one resource instance.
*/
public ResilientHttpClient(final Logger lgr,
final HttpClient httpClient) {
if (null == lgr) {
throw new IllegalArgumentException("Logger is null");
}
this.logger = lgr;
if (null == httpClient) {
throw new IllegalArgumentException("HttpClient is null");
}
this.httpClient = httpClient;
}
public String executeHttpRequest(String circuitbreakerInstanceName, HttpRequest httpRequest) {
try {
/* circuitbreakerInstanceName is future place holder for .yml configuration see : https://resilience4j.readme.io/docs/getting-started-3 */
RetryConfig config = RetryConfig.<HttpResponse>custom()
.waitDuration(Duration.ofMillis(1000))
.retryOnResult(response -> response.statusCode() == 500)
.retryOnException(e -> e instanceof ArithmeticException)
.retryExceptions(IOException.class, TimeoutException.class)
//.ignoreExceptions(BusinessException.class, OtherBusinessException.class)
.build();
// Create a RetryRegistry with a custom global configuration
RetryRegistry registry = RetryRegistry.of(config);
// Get or create a Retry from the registry -
// Retry will be backed by the default config
Retry retryWithDefaultConfig = registry.retry(circuitbreakerInstanceName);
Supplier<HttpResponse> supplier = () -> this.httpClient.send(httpRequest, HttpResponse.BodyHandlers.ofString());
Supplier<String> supplierWithResultAndExceptionHandler = SupplierUtils
.andThen(supplier, (result, exception) -> "Hello Recovery");
Supplier<HttpResponse> supplierWithResultHandling = SupplierUtils.andThen(supplier, result -> {
if (result.statusCode() == HttpStatus.BAD_REQUEST.value()) {
throw new RuntimeException("400");
} else if (result.statusCode() == HttpStatus.INTERNAL_SERVER_ERROR.value()) {
throw new RuntimeException("500");
}
return result;
});
HttpResponse<String> response = retryWithDefaultConfig.executeSupplier(supplierWithResultHandling);
String responseBody = response.body();
return responseBody;
} catch (Exception ex) {
throw new RuntimeException((ex));
}
}
}
The issue I am having is:
The line:
Supplier<HttpResponse> supplier = () - > this.httpClient.send(httpRequest, HttpResponse.BodyHandlers.ofString());
is giving an error (in intelliJ) of "unhandled exceptions" "IOException, InterruptedException"
So modifying the method to be:
public String executeHttpRequest(String circuitbreakerInstanceName, HttpRequest httpRequest) throws IOException, InterruptedException {
"feels wrong". But even when I try it...it doesn't resolve anything. :(
It is probably some lamda checked-exception voodoo.
But more to the point:
So I don't know if the way I've brought together the 2 partials is even correct. The samples are a little lacking in the fully-working area.
Thank for any help. Getting a basic httpclient "retry" a few times shouldn't be too hard. But I'm hitting my head against the wall.
My gradle dependencies.
dependencies {
implementation group: 'javax.inject', name: 'javax.inject', version: javaxInjectVersion
implementation group: 'org.slf4j', name: 'slf4j-api', version: slf4jVersion
implementation group: 'org.springframework', name: 'spring-web', version: springWebVersion
implementation "io.github.resilience4j:resilience4j-circuitbreaker:${resilience4jVersion}"
implementation "io.github.resilience4j:resilience4j-ratelimiter:${resilience4jVersion}"
implementation "io.github.resilience4j:resilience4j-retry:${resilience4jVersion}"
implementation "io.github.resilience4j:resilience4j-bulkhead:${resilience4jVersion}"
implementation "io.github.resilience4j:resilience4j-cache:${resilience4jVersion}"
implementation "io.github.resilience4j:resilience4j-timelimiter:${resilience4jVersion}"
testCompile group: 'junit', name: 'junit', version: junitVersion
}
and
resilience4jVersion = '1.5.0'
slf4jVersion = "1.7.30"
javaxInjectVersion = "1"
springWebVersion = '5.2.8.RELEASE'
junitVersion = "4.12"

Answer 1

just out of interest:
Which Java version are you using? Java 11?
Why can't you use Spring Boot? The Resilience4j Spring Boot starter simplifies the configuration a lot.
If you configure retryOnResult(response -> response.getStatus() == 500), you don't have to use SupplierUtils anymore to map a HttpResponse with a certain status code to a runtime exception.
RetryConfig config = RetryConfig.<HttpResponse<String>>custom()
.waitDuration(Duration.ofMillis(1000))
.retryOnResult(response -> response.statusCode() == 500)
.retryExceptions(IOException.class, TimeoutException.class)
.build();
Please don't create Registries and Configs inside of executeHttpRequest, but inject them into your Constructor.
You can create a static method like this:
public static <T> HttpResponse<T> executeHttpRequest(Callable<HttpResponse<T>> callable, Retry retry, CircuitBreaker circuitBreaker) throws Exception {
return Decorators.ofCallable(callable)
.withRetry(retry)
.withCircuitBreaker(circuitBreaker)
.call();
}
and invoke the method as follows:
HttpResponse<String> response = executeHttpRequest(
() -> httpClient.send(request, HttpResponse.BodyHandlers.ofString()),
retry,
circuitBreaker);