Various examples of retries with Mutiny

Retry.java

//usr/bin/env jbang "$0" "$@" ; exit $?

//DEPS io.smallrye.reactive:smallrye-mutiny-vertx-web-client:1.1.0
//DEPS io.smallrye.reactive:mutiny:0.7.0
//DEPS org.slf4j:slf4j-nop:1.7.30

package io.vertx.mutiny.retry;

import io.smallrye.mutiny.Uni;
import io.vertx.mutiny.core.Vertx;
import io.vertx.mutiny.ext.web.client.WebClient;

import java.time.Duration;
import java.util.Random;

/**
 * Various examples of retries.
 * CTRL+C to exist.
 */
public class Retry {

    public static void main(String[] args) {
        Vertx vertx = Vertx.vertx();
        WebClient client = WebClient.create(vertx);
        // Just start a picky service failing 50% of the times.
        startPickyService(vertx);

        System.out.println("Hit CTRL+C to exit the program");

        // Retrying forever
        invokePickyService(client)
                .onFailure().retry().indefinitely()
                .subscribe().with(item -> System.out.println("[Retrying forever]: " + item));

        // Retrying at most twice
        invokePickyService(client)
                .onFailure().retry().atMost(2)
                .subscribe().with(
                        item -> System.out.println("[Retrying atMost(2)]: " + item),
                        failure -> System.out.println("[Retrying atMost(2) failed]: " + failure.getMessage())
        );

        // Retrying with backoff
        invokePickyService(client)
                .onFailure().retry().withBackOff(Duration.ofSeconds(1)).withJitter(0.2).atMost(10)
                .subscribe().with(
                    item -> System.out.println("[Retrying backoff]: " + item),
                    failure -> System.out.println("[Retrying backoff failed]: " + failure.getMessage())
        );

        // Retrying with backoff and deadline
        invokePickyService(client)
                .onFailure().retry().withBackOff(Duration.ofSeconds(1)).withJitter(0.2)
                    .expireIn(5000)
                .subscribe().with(
                item -> System.out.println("[Retrying backoff with deadline]: " + item),
                failure -> System.out.println("[Retrying backoff with deadline]: " + failure.getMessage())
        );
    }

    private static Uni<String> invokePickyService(WebClient client) {
        return client.getAbs("http://localhost:8080")
                .send()
                .onItem().transform(resp -> {
                    if (resp.statusCode() == 200) {
                        return resp.bodyAsString();
                    } else {
                        throw  new IllegalStateException(resp.bodyAsString());
                    }
                });
    }

    private static void startPickyService(Vertx vertx) {
        Random random = new Random();
        vertx.createHttpServer()
                .requestHandler(req -> {
                    if (random.nextBoolean()) {
                        req.response().endAndForget("Hello!");
                    } else {
                        req.response().setStatusCode(500).endAndForget("Not in a mood");
                    }
                })
                .listenAndAwait(8080);
    }

}

In addition, i also tried to retrieve the IllegalStateException suppressed showing the number of retries attempted:

.onFailure((failure) -> Arrays.stream(failure.getSuppressed()).anyMatch(f -> f instanceof IllegalStateException))

It exits from the retry block after the first iteration (http client stub is called only once in my test)

Hello @cescoffier,

Is it possible to retry a request and for each request, wait a certain ammount of seconds? The following code waits 30 seconds but it is considering all of the retries. What i would like to do is to wait 30 seconds for the response everytime it retries.

WebClient.create(vertx)
.get(endpoint)
.send()
.onItem()
.transformToMulti(response -> {
........................................................
return Uni.createFrom().item(response.bodyAsJsonObject().getJsonArray("content")).toMulti();
})
.onFailure()
.retry()
.withBackOff(Duration.ofSeconds(5), Duration.ofSeconds(10))
.withJitter(0.7)
.atMost(3)
.onFailure().invoke(error -> log.error("Didn't work.")
.toUni()
.await()
.atMost(Duration.ofSeconds(30));

Thank you!