Package org.mockserver.mock.action.http

Class ForwardRetryPolicy

java.lang.Object

org.mockserver.mock.action.http.ForwardRetryPolicy

public final class ForwardRetryPolicy
extends Object

Stateless retry logic for forwarded/proxied requests. Re-issues a request to its upstream up to maxRetries times when the previous attempt produced a transient failure — a connection-level exception, or an upstream response of 502/503/504 — provided the HTTP method is idempotent. Non-idempotent methods (POST, PATCH) are never retried, so a request is never silently executed twice.

The whole policy is inert when maxRetries <= 0: execute(java.lang.String, int, long, java.util.function.Supplier<java.util.concurrent.CompletableFuture<org.mockserver.model.HttpResponse>>) simply returns the first attempt's future, preserving the historical "forward exactly once" behaviour.

Retries are chained asynchronously off the supplied future (never blocking the event loop). A linear back-off (backoffMillis * attemptNumber) is applied between attempts via CompletableFuture.delayedExecutor(long, java.util.concurrent.TimeUnit, java.util.concurrent.Executor).

Method Summary

Modifier and Type	Method	Description
static CompletableFuture<HttpResponse>	execute(String method, int maxRetries, long backoffMillis, Supplier<CompletableFuture<HttpResponse>> attempt)	Run attempt with retry.
static boolean	isIdempotent(String method)	Whether a request using the given HTTP method may be retried.
static boolean	isTransientFailure(HttpResponse response, Throwable throwable)	Whether a completed attempt (response or throwable) should be retried.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

isIdempotent

public static boolean isIdempotent(String method)

Whether a request using the given HTTP method may be retried.

Parameters:

method - the request method (case-insensitive); null/blank is treated as non-idempotent

isTransientFailure

public static boolean isTransientFailure(HttpResponse response,
 Throwable throwable)

Whether a completed attempt (response or throwable) should be retried. A non-null throwable is always transient; a non-null response is transient only when its status code is 502/503/504.

execute

public static CompletableFuture<HttpResponse> execute(String method,
 int maxRetries,
 long backoffMillis,
 Supplier<CompletableFuture<HttpResponse>> attempt)

Run attempt with retry. When maxRetries <= 0 or the method is non-idempotent the first attempt's future is returned unchanged. Otherwise a transient failure (exception or 502/503/504) triggers up to maxRetries further attempts with linear back-off; the future from the last attempt is returned once a non-transient result is produced or the retry budget is exhausted.

Parameters:

method - the request HTTP method (drives the idempotency check)

maxRetries - maximum number of retries (0 disables retry)

backoffMillis - base linear back-off between attempts in milliseconds

attempt - supplies a fresh attempt future each time it is invoked

Returns:

a future completing with the final attempt's response