java spring webflux：如何从同步调用发布事件以进行异步处理？

Question

我有一个同步调用的方法。通过这个方法，我想发布另一个将被异步处理的事件。例如：

正在使用参数调用同步方法M，需要将此参数发送到其他服务器X。M应尽快返回，但X可能会关闭。如果X关闭，异步处理应该在几秒钟后重试几次

所以我有一个处理单个均衡器/参数的代码：

 return webClient
                .post()
                .uri(...)
                .syncBody(...)
                .retrieve().bodyToMono(...)
                .retryWhen {...}
                .subscribeOn(Schedulers.boundedElastic())

但如何从同步调用发布新的事件/参数

Answer 1

spring提供的一个很好的开箱即用的解决方案叫做Spring Cloud Gateway，它正好满足了您的要求：

这是一款无代码应用程序，您可以立即启动，并使用yaml配置配置所有路由，还可以通过配置轻松为每条路由应用所需的重试退避等：

它提供了一个内置的重试网关过滤器工厂，可以提供所需的解决方案

The Retry GatewayFilter factory supports the following parameters:

retries: The number of retries that should be attempted.

statuses: The HTTP status codes that should be retried, represented by using org.springframework.http.HttpStatus.

methods: The HTTP methods that should be retried, represented by using org.springframework.http.HttpMethod.

series: The series of status codes to be retried, represented by using org.springframework.http.HttpStatus.Series.

exceptions: A list of thrown exceptions that should be retried.

backoff: The configured exponential backoff for the retries. Retries are performed after a backoff interval of firstBackoff * (factor ^ n), where n is the iteration. If maxBackoff is configured, the maximum backoff applied is limited to maxBackoff. If basedOnPreviousValue is true, the backoff is calculated byusing prevBackoff * factor.

The following defaults are configured for Retry filter, if enabled:

retries: Three times

series: 5XX series

methods: GET method

exceptions: IOException and TimeoutException

backoff: disabled

示例Yaml配置再次无需代码：）：

spring:
  cloud:
    gateway:
      routes:
      - id: retry_test
        uri: http://localhost:8080/flakey
        predicates:
        - Host=*.retry.com
        filters:
        - name: Retry
          args:
            retries: 3
            statuses: BAD_GATEWAY
            methods: GET,POST
            backoff:
              firstBackoff: 10ms
              maxBackoff: 50ms
              factor: 2
              basedOnPreviousValue: false