Package com.linecorp.armeria.client.circuitbreaker

Interface CircuitBreakerStrategy

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface CircuitBreakerStrategy

Determines whether a Response should be reported as a success or a failure to a CircuitBreaker. If you need to determine whether the request was successful by looking into the Response content, use CircuitBreakerStrategyWithContent.

Method Summary

Modifier and Type	Method	Description
static CircuitBreakerStrategy	onServerErrorStatus()	Returns the CircuitBreakerStrategy that determines a Response as successful when its HttpStatus is not HttpStatusClass.SERVER_ERROR and there was no Exception raised.
static CircuitBreakerStrategy	onStatus(BiFunction<HttpStatus,Throwable,Boolean> function)	Returns the CircuitBreakerStrategy that determines a Response as successful using the specified BiFunction.
CompletionStage<Boolean>	shouldReportAsSuccess(ClientRequestContext ctx, Throwable cause)	Returns a CompletionStage that contains true, false or null which indicates a Response is successful or not.

Method Details

onServerErrorStatus

static CircuitBreakerStrategy onServerErrorStatus()

Returns the CircuitBreakerStrategy that determines a Response as successful when its HttpStatus is not HttpStatusClass.SERVER_ERROR and there was no Exception raised.

onStatus

static CircuitBreakerStrategy onStatus(BiFunction<HttpStatus,Throwable,Boolean> function)

Returns the CircuitBreakerStrategy that determines a Response as successful using the specified BiFunction.

Parameters:

function - the BiFunction that returns true, false or null according to the HttpStatus and Throwable. If true is returned, CircuitBreaker.onSuccess() is called so that the CircuitBreaker increases its success count and uses it to make a decision to close or open the circuit. If false is returned, it works the other way around. If null is returned, the CircuitBreaker ignores it.

shouldReportAsSuccess

CompletionStage<Boolean> shouldReportAsSuccess(ClientRequestContext ctx, @Nullable Throwable cause)

Returns a CompletionStage that contains true, false or null which indicates a Response is successful or not. If true is returned, CircuitBreaker.onSuccess() is called so that the CircuitBreaker increases its success count and uses it to make a decision to close or open the circuit. If false is returned, it works the other way around. If null is returned, the CircuitBreaker ignores it. To retrieve the ResponseHeaders, you can use the specified ClientRequestContext:

 CompletionStage<Backoff> shouldReportAsSuccess(ClientRequestContext ctx, @Nullable Throwable cause) {
     if (cause != null) {
         return CompletableFuture.completedFuture(false);
     }

     ResponseHeaders responseHeaders = ctx.log().responseHeaders();
     if (responseHeaders.status().codeClass() == HttpStatusClass.SERVER_ERROR) {
         return CompletableFuture.completedFuture(false);
     }
     ...
 }
 

Parameters:

ctx - the ClientRequestContext of this request

cause - the Throwable which is raised while sending a request. null if there's no exception.