org.zalando.riptide.OriginalStackTracePlugin Maven / Gradle / Ivy

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package org.zalando.riptide;

import org.apiguardian.api.API;
import org.springframework.http.client.ClientHttpResponse;

import java.util.concurrent.CompletableFuture;
import java.util.function.Supplier;

import static com.google.common.collect.ObjectArrays.concat;
import static org.apiguardian.api.API.Status.STABLE;
import static org.zalando.fauxpas.FauxPas.partially;

/**
 * Preserves the original stack traces of failed requests. Requests in Riptide are executed asynchronously by default.
 * That has the unfortunate side-effect that stack traces from exceptions that happen when processing the response will
 * not contain everything that is needed to trace back to the caller.
 *
 * This plugin will modify the stack trace of any thrown exception and appending the stack trace elements of the
 * original stack trace
 */
@API(status = STABLE)
public final class OriginalStackTracePlugin implements Plugin {

    @Override
    public RequestExecution prepare(final RequestArguments arguments, final RequestExecution execution) {
        return () -> {
            final CompletableFuture future = execution.execute();
            // let's do the "heavy" stack trace work while the request is already on its way
            final Supplier original = keepOriginalStackTrace();
            return future.exceptionally(partially(cause -> {
                cause.setStackTrace(concat(cause.getStackTrace(), original.get(), StackTraceElement.class));
                throw cause;
            }));
        };
    }

    /**
     * A good way to store a stacktrace away efficiently is to simply construct an exception. Later, if you
     * want to inspect the stacktrace call exception.getStackTrace() which will do the slow work of
     * resolving the stack frames to methods.
     * 
     *  keepOriginalStackTrace() {
        return new Exception()::getStackTrace;
    }

}