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Part05 spring cloud openfeign 服务容错隔离.md

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spring cloud openfeign 服务容错隔离

相关文档

  • 官方文档地址：

    https://docs.spring.io/spring-cloud/docs/current/reference/html/

https://docs.spring.io/spring-cloud-openfeign/docs/current/reference/html

https://docs.spring.io/spring-cloud-openfeign/docs/current/reference/html/appendix.html

https://docs.spring.io/spring-cloud-circuitbreaker/docs/current/reference/html/

https://docs.spring.io/spring-cloud-circuitbreaker/docs/current/reference/html/#bulkhead-pattern-supporting

https://resilience4j.readme.io/docs

  • 示例源码地址：

    /~https://github.com/zfhlm/mrh-example/tree/main/mrh-spring-cloud

容错隔离说明

  • 基于 resilience4j bulkhead 实现，需要引入 maven 依赖：

    <dependency>
    <groupId>io.github.resilience4j</groupId>
    <artifactId>resilience4j-bulkhead</artifactId>
</dependency>

  • 提供了两种隔离方式：

    FixedThreadPoolBulkhead             # 固定数量线程池隔离，默认使用此方式

SemaphoreBulkhead                   # 基于信号量进行隔离

  • 当 feign.circuitbreaker.group.enabled=false 时，每个 熔断限时实例 作为一个隔离仓：

    ①，如果实例生效范围是 service 级别，那每个 service 一个隔离仓

②，如果实例生效范围是 client 级别，那么每个 client 一个隔离仓

③，如果实例生效范围是 method 级别，那么每个 method 一个隔离仓

隔离仓的名称 = 实例名称

  • 当 feign.circuitbreaker.group.enabled=true 时，每个 client 作为一个隔离仓：

    ①，如果实例生效范围是 service 级别，仍然是每个 client 作为一个隔离仓

②，如果实例生效范围是 client 级别，仍然是每个 client 作为一个隔离仓

③，如果实例生效范围是 method 级别，仍然是每个 client 作为一个隔离仓

隔离仓的名称 = @FeignClient#contextId()

  • 线程池隔离必须考虑的问题：

    每个隔离仓都有自己单独一个线程池，必须防止线程池数量过多，性能急剧下降

容错隔离配置

  • 线程池隔离，添加 application.yml 配置：

    spring:
  cloud:
    circuitbreaker:
      bulkhead:
        resilience4j:
          enabled: true
      resilience4j:
        enableSemaphoreDefaultBulkhead: false

feign:
  circuitbreaker:
    group:
      enabled: true
resilience4j:
  thread-pool-bulkhead:
    configs:
      default:
        maxThreadPoolSize: 20
        coreThreadPoolSize: 1
        queueCapacity: 5
    instances:
      # 隔离仓名称
      organ-client:
        baseConfig: default

  • 信号量隔离，添加 application.yml 配置：

    spring:
  cloud:
    circuitbreaker:
      bulkhead:
        resilience4j:
          enabled: true
      resilience4j:
        enableSemaphoreDefaultBulkhead: true

feign:
  circuitbreaker:
    group:
      enabled: true
resilience4j:
  bulkhead:
    configs:
      default:
        maxConcurrentCalls: 30
    instances:
      # 隔离仓名称
      organ-client:
        baseConfig: default

全局默认配置

  • 创建覆盖默认配置的 Customizer 实现：

    public class ConfigureDefaultBulkheadProviderCustomizer implements Customizer<Resilience4jBulkheadProvider> {

    private static final String name = "default";    // 默认配置名称

    private ThreadPoolBulkheadProperties threadPoolBulkheadProperties;

    private BulkheadProperties bulkheadProperties;

    public ConfigureDefaultBulkheadProviderCustomizer(
            ThreadPoolBulkheadProperties threadPoolBulkheadProperties,
            BulkheadProperties bulkheadProperties) {
        super();
        this.threadPoolBulkheadProperties = threadPoolBulkheadProperties;
        this.bulkheadProperties = bulkheadProperties;
    }

    @Override
    public void customize(Resilience4jBulkheadProvider provider) {

        // 线程池隔离默认配置
        ThreadPoolBulkheadConfig defaultThreadPoolBulkheadConfig = Optional.ofNullable(this.threadPoolBulkheadProperties.getConfigs().get(name))
                .map(properties -> this.threadPoolBulkheadProperties.createThreadPoolBulkheadConfig(name, new CompositeCustomizer<>(Collections.emptyList())))
                .orElse(ThreadPoolBulkheadConfig.ofDefaults());

        // 信号量隔离默认配置
        BulkheadConfig defaultBulkheadConfig = Optional.ofNullable(this.bulkheadProperties.getConfigs().get(name))
                .map(properties -> this.bulkheadProperties.createBulkheadConfig(properties, new CompositeCustomizer<>(Collections.emptyList()), name))
                .orElse(BulkheadConfig.ofDefaults());

        // 添加到默认配置
        provider.configureDefault(id -> new Resilience4jBulkheadConfigurationBuilder()
                .bulkheadConfig(defaultBulkheadConfig)
                .threadPoolBulkheadConfig(defaultThreadPoolBulkheadConfig)
                .build());

    }

}

  • 注册 Customizer 为 bean：

    @Bean
public ConfigureDefaultBulkheadProviderCustomizer configureDefaultBulkheadProviderCustomizer(
        ThreadPoolBulkheadProperties threadPoolBulkheadProperties,
        BulkheadProperties bulkheadProperties) {
    return new ConfigureDefaultBulkheadProviderCustomizer(threadPoolBulkheadProperties, bulkheadProperties);
}

线程池隔离仓 线程上下文传递

  • 查看 openfeign circuitbreaker 相关实现：

    org.springframework.cloud.openfeign.FeignCircuitBreakerInvocationHandler


private Supplier<Object> asSupplier(final Method method, final Object[] args) {
    final RequestAttributes requestAttributes = RequestContextHolder.getRequestAttributes();
    return () -> {
        try {
            RequestContextHolder.setRequestAttributes(requestAttributes);
            return dispatch.get(method).invoke(args);
        }
        catch (RuntimeException throwable) {
            throw throwable;
        }
        catch (Throwable throwable) {
            throw new RuntimeException(throwable);
        }
    };
}

可以发现默认已经对 RequestAttributes 线程上下文进行了传递

  • 如果需要对其他线程上下文进行传递，需要重写并替换相关实现：

    org.springframework.cloud.openfeign.FeignCircuitBreaker