spring cloud openfeign 服务熔断限时

服务熔断限时

服务限时，限制请求最大等待时间，超过则中断请求并抛出异常

服务熔断，考虑到多层依赖：

    service-A                                   service-B                                service-C
.................................             .................................             .............
||--------------|               |             ||--------------|               |             |           |
|| circuit open |               |             || circuit open |               |             |           |
||<-------------|               |             ||<-------------|               |             |           |
|| circuit half |               |------------>|| circuit half |               |------------>|           |
||<-------------| half or close |             ||<-------------| half or close |             |           |
||              |-------------->|             ||              |-------------->|             |           |
||                              |             ||                              |             |           |
||                  http 200    |<------------||                  http 200    |<------------|           |
||              |<--------------|             ||              |<--------------|             |           |
||              |  decode error |             ||              |  decode error |             |           |
||    calculate |<--------------|             ||    calculate |<--------------|             |           |
||<-------------|               |             ||<-------------|               |             |           |
.................................             .................................             .............

(calculate 统计响应结果，根据结果统计值转换 open、half open、close 三种熔断状态)

①，服务有使用 openfeign 进行远程调用才开启熔断，例如 service-C 无远程调用则无需开启

②，熔断默认统计所有异常，可以自定义异常解码器抛出不同类型异常，然后忽略统计某些异常

③，熔断异常应该在服务内部被处理完成，不宜再往上传递，否则会导致调用链每层都触发熔断

服务调用开启熔断限时

引入 maven 依赖：

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-circuitbreaker-resilience4j</artifactId>
</dependency>

手动注册 FallbackFactory：

@Configuration
public class FallbackConfiguration {

    @Bean
    public OrganClientFallbackFactory organClientFallbackFactory() {
        return new OrganClientFallbackFactory();
    }

}

添加 application.yml 配置开启熔断：

feign:
  circuitbreaker:
    enabled: true
    group.enabled: false
    alphanumeric-ids.enabled: false

熔断限时默认配置

使用 resilience4j 的注入配置，从中读取以下两个配置，作为熔断、限时默认配置：
```
resilience4j.circuitbreaker.configs.default

resilience4j.timelimiter.configs.default
```

读取配置并添加到熔断限时默认配置，创建 Customizer 实现类：

public class ConfigureDefaultCircuitBreakerFactoryCustomizer implements Customizer<Resilience4JCircuitBreakerFactory> {

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

    private CircuitBreakerProperties circuitBreakerProperties;

    private TimeLimiterProperties timeLimiterProperties;

    public ConfigureDefaultCircuitBreakerFactoryCustomizer(
            CircuitBreakerProperties circuitBreakerProperties,
            TimeLimiterProperties timeLimiterProperties) {
        super();
        this.circuitBreakerProperties = circuitBreakerProperties;
        this.timeLimiterProperties = timeLimiterProperties;
    }

    @Override
    public void customize(Resilience4JCircuitBreakerFactory circuitBreakerFactory) {

        // 读取熔断默认配置
        CircuitBreakerConfig defaultCircuitBreakerConfig = Optional.ofNullable(this.circuitBreakerProperties.getConfigs().get(name))
                .map(properties -> this.circuitBreakerProperties.createCircuitBreakerConfig(name, properties, new CompositeCustomizer<>(Collections.emptyList())))
                .orElse(CircuitBreakerConfig.ofDefaults());

        // 读取限时默认配置
        TimeLimiterConfig defaultTimeLimiterConfig = Optional.ofNullable(this.timeLimiterProperties.getConfigs().get(name))
                .map(properties -> this.timeLimiterProperties.createTimeLimiterConfig(name, properties, new CompositeCustomizer<>(Collections.emptyList())))
                .orElse(TimeLimiterConfig.ofDefaults());

        // 配置到断路器工厂
        circuitBreakerFactory.configureDefault(id -> new Resilience4JConfigBuilder(id)
                .circuitBreakerConfig(defaultCircuitBreakerConfig)
                .timeLimiterConfig(defaultTimeLimiterConfig)
                .build());
    }

}

将 Customizer 实现类注册为 bean：

@Bean
public ConfigureDefaultCircuitBreakerFactoryCustomizer configureDefaultCircuitBreakerFactoryCustomizer(
        CircuitBreakerProperties circuitBreakerProperties,
        TimeLimiterProperties timeLimiterProperties) {
    return new ConfigureDefaultCircuitBreakerFactoryCustomizer(circuitBreakerProperties, timeLimiterProperties);
}

如果以下配置存在，则会覆盖默认配置：

# 这里不再解释参数，查看 resilience4j 官方文档，或查看博客 [spring cloud gateway 熔断 resilience4j]
resilience4j:
  circuitbreaker:
    configs:
      default:
        failureRateThreshold: 50
        slowCallRateThreshold: 100
        slowCallDurationThreshold: 60s
        waitDurationInOpenState: 60s
        permittedNumberOfCallsInHalfOpenState: 10
        slidingWindowType: COUNT_BASED
        slidingWindowSize: 100
        minimumNumberOfCalls: 10
        ignoreExceptions:
          - org.lushen.mrh.cloud.reference.supports.ServiceBusinessException
  timelimiter:
    configs:
      default:
        timeoutDuration: 5s
        cancelRunningFuture: true

熔断限时默认每个 client 的 method 单独一个实例，实例之间互不影响，可查看源码：

org.springframework.cloud.openfeign.FeignCircuitBreakerInvocationHandler

org.springframework.cloud.openfeign.FeignAutoConfiguration.CircuitBreakerPresentFeignTargeterConfiguration.DefaultCircuitBreakerNameResolver

使用 alphanumeric-ids 更改熔断限时实例配置

需要开启 alphanumeric-ids 添加以下配置：

feign.circuitbreaker.alphanumeric-ids.enabled: true

添加 application.yml 熔断限流配置：

# 这里不再解释参数，查看 resilience4j 官方文档，或查看博客 [spring cloud gateway 熔断 resilience4j]
resilience4j:
  circuitbreaker:
    configs:
      default:
        failureRateThreshold: 50
        slowCallRateThreshold: 100
        slowCallDurationThreshold: 60s
        waitDurationInOpenState: 60s
        permittedNumberOfCallsInHalfOpenState: 10
        slidingWindowType: COUNT_BASED
        slidingWindowSize: 100
        minimumNumberOfCalls: 10
        ignoreExceptions:
          - org.lushen.mrh.cloud.reference.supports.ServiceBusinessException
    instances:
      OrganClientget:
        baseConfig: default
      OrganClientadd:
        baseConfig: default
  timelimiter:
    configs:
      default:
        timeoutDuration: 5s
        cancelRunningFuture: true
    instances:
      OrganClientget:
        baseConfig: default
      OrganClientadd:
        baseConfig: default

扩展熔断限时实例名称生成方式

基于官方提供的接口 CircuitBreakerNameResolver，我们可以调整实例名称生成方式，进而达到更改实例的范围：

// 每个 openfeign 订阅的服务 作为一个实例，服务级别的熔断，粒度比较粗糙

public class ServiceNameCircuitBreakerNameResolver implements CircuitBreakerNameResolver {
    @Override
    public String resolveCircuitBreakerName(String feignClientName, Target<?> target, Method method) {
        return target.name();
    }
}

// 每个 openfeign client 作为一个实例，client 级别的熔断，粒度中等

public class ClientNameCircuitBreakerNameResolver implements CircuitBreakerNameResolver {
    @Override
    public String resolveCircuitBreakerName(String feignClientName, Target<?> target, Method method) {
        return feignClientName;
    }
}

// 每个 openfeign client method 作为一个实例，自定义的名称生成方式，method 级别的熔断，粒度最小

public class MethodNameCircuitBreakerNameResolver implements CircuitBreakerNameResolver {
    @Override
    public String resolveCircuitBreakerName(String feignClientName, Target<?> target, Method method) {
        StringBuilder builder = new StringBuilder();
        // 客户端名称
        for(char ch : feignClientName.toCharArray()) {
            if(Character.isLetter(ch) || Character.isDigit(ch) || ch == '-') {
                builder.append(ch);
            }
        }
        // 连接符
        if(builder.charAt(builder.length()-1) != '-') {
            builder.append('-');
        }
        // 方法名称
        for(char ch : method.getName().toCharArray()) {
            if(Character.isLetter(ch) || Character.isDigit(ch)) {
                builder.append(ch);
            }
        }
        // guava 库，统一转换
        return CaseFormat.LOWER_CAMEL.to(CaseFormat.LOWER_HYPHEN, builder.toString());
    }
}

选择一个自定义实例名称解析器：

@Bean
public ClientNameCircuitBreakerNameResolver clientNameCircuitBreakerNameResolver() {
    return new ClientNameCircuitBreakerNameResolver();
}

添加 application.yml 熔断实例配置：

# 这里不再解释参数，查看 resilience4j 官方文档，或查看博客 [spring cloud gateway 熔断 resilience4j]
resilience4j:
  circuitbreaker:
    configs:
      default:
        failureRateThreshold: 50
        slowCallRateThreshold: 100
        slowCallDurationThreshold: 60s
        waitDurationInOpenState: 60s
        permittedNumberOfCallsInHalfOpenState: 10
        slidingWindowType: COUNT_BASED
        slidingWindowSize: 100
        minimumNumberOfCalls: 10
        ignoreExceptions:
          - org.lushen.mrh.cloud.reference.supports.ServiceBusinessException
    instances:
      # 名称要与解析器生成名称一致
      organ-client:
        baseConfig: default
  timelimiter:
    configs:
      default:
        timeoutDuration: 5s
        cancelRunningFuture: true
    instances:
      # 名称要与解析器生成名称一致
      organ-client:
        baseConfig: default

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Part04 spring cloud openfeign 服务熔断限时.md

Part04 spring cloud openfeign 服务熔断限时.md

spring cloud openfeign 服务熔断限时

相关文档

服务熔断限时

服务调用开启熔断限时

熔断限时默认配置

使用 alphanumeric-ids 更改熔断限时实例配置

扩展熔断限时实例名称生成方式

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服务熔断限时

服务调用开启熔断限时

熔断限时默认配置

使用 alphanumeric-ids 更改熔断限时实例配置

扩展熔断限时实例名称生成方式