Spring Boot + Spring Cloud CircutBreaker Resilience4j

Spring Boot と Spring Cloud Circuit Breaker の Rejilience4j を組み合わせたサーキットブレーカーサンプルです。

概要

Spring Cloud Circuit Breaker によって提供されたサーキットブレーカー機能を利用します。いくつか実装を選択することができますが、本サンプルでは Rejilience4j を利用します。

前提条件

Java 17 以降
Maven 3.6 以降
HTTP エンドポイントを呼び出すために、curl を利用します。

依存ライブラリ

spring-boot-starter-web 以外に、以下のライブラリが必要です。詳細は、pom.xml を参照してください。

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

ビルドおよび実行方法

以下のコマンドでビルドします。

mvn clean package

以下のコマンドでSpring Boot アプリケーションを起動します。

mvn spring-boot:run

以下のようなログが表示され、アプリケーションが起動します。

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.5.5)

2021-10-11 14:03:12.082  INFO 22471 --- [           main] o.p.w.s.cb.sb.r4j.SampleApplication      : Starting SampleApplication using Java 17.0.11 on NICKEL with PID 22471 (/work/waf-java-samples/circuitbreaker/04-springboot-cb-r4j/target/classes started by moris in /work/waf-java-samples/circuitbreaker/04-springboot-cb-r4j)
2021-10-11 14:03:12.090  INFO 22471 --- [           main] o.p.w.s.cb.sb.r4j.SampleApplication      : No active profile set, falling back to default profiles: default
2021-10-11 14:03:14.859  INFO 22471 --- [           main] o.s.cloud.context.scope.GenericScope     : BeanFactory id=dc13a1f0-731b-3a8e-9bc3-ef28ee6e6c54
2021-10-11 14:03:16.618  INFO 22471 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2021-10-11 14:03:16.647  INFO 22471 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2021-10-11 14:03:16.647  INFO 22471 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.53]

ポートを変更したい場合は、コマンドラインに以下の引数を付加して実行してください。

mvn spring-boot:run -Dspring-boot.run.arguments=--server.port=8888

サンプルの説明

/test1 と /test2 のエンドポイントが定義しており、実装方法は異なりました同じ振る舞いをします。/test1 では、プログラムによってサーキットブレーカーを構成した例、/test2 は @CircutBreaker アノテーションで構成されています。

/test1 のエンドポンイトから呼び出されるサービスは、プログラムでサーキットブレーカーを構成した例です。 SampleConfiguration で定義されています。

    @Bean
    public Customizer<Resilience4JCircuitBreakerFactory> defaultCustomizer() {
        CircuitBreakerConfig config = CircuitBreakerConfig.custom()
            .slidingWindowType(SlidingWindowType.COUNT_BASED)
            .slidingWindowSize(10)
            .failureRateThreshold(30)
            .permittedNumberOfCallsInHalfOpenState(5)
            .recordExceptions(HttpServerErrorException.class, 
                HttpClientErrorException.TooManyRequests.class)
            .automaticTransitionFromOpenToHalfOpenEnabled(true)
            .waitDurationInOpenState(Duration.ofSeconds(5))
            .build();

        return factory -> factory
            .configure(builder -> builder
                .circuitBreakerConfig(config).build(), "myconfig1");
    }

/test2 のエンドポイントから呼び出されるサービスは、@CircuitBreaker アノテーションで構成されています。構成値は、application.yml で定義されています。

resilience4j.circuitbreaker:
    instances:
        myconfig2:
            slidingWindowSize: 10
            permittedNumberOfCallsInHalfOpenState: 5
            waitDurationInOpenState: 5000
            failureRateThreshold: 30
            registerHealthIndicator: true
            automatic-transition-from-open-to-half-open-enabled: true
            record-exceptions:
            - org.springframework.web.client.HttpServerErrorException
            - org.springframework.web.client.HttpClientErrorException.TooManyRequests

/test1 も /test2 もほぼ同じ振る舞いになるように、構成設定してあします。

アプリケーションへの操作

test.sh を実行します。

サーキットブレーカーが OPENになると、io.github.resilience4j.circuitbreaker.CallNotPermittedException CircuitBreaker 'myconfig1' is OPEN and does not permit further calls の例外がスローされ、外部サービス呼び出しはブロックされます。

CLOSED -> OPEN

初期状態（CLOSED） ->　OPEN へ移行する例です。10回のスライディングウィンドウの失敗率が30%を超える（本例だと3回）と OPEN へ遷移しますが、最低でもスライディングウィンドウ数の呼び出しがないと評価されません。外部サービス呼び出しを3回に1回失敗するようにしてあり、10回目の呼び出し後に失敗率が評価され、OPEN に遷移しています。OPEN に遷移後は、外部サービス呼び出しはブロックされます。

2021-10-11 14:29:17.224  INFO 25662 --- [nio-8080-exec-1] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:29:17.269  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/500
2021-10-11 14:29:17.849 ERROR 25662 --- [nio-8080-exec-1] o.p.wa.sample.cb.sb.r4j.SampleService    : org.springframework.web.client.HttpServerErrorException$InternalServerError 500 INTERNAL SERVER ERROR: [no body]
2021-10-11 14:29:17.849  INFO 25662 --- [nio-8080-exec-1] o.p.wa.sample.cb.sb.r4j.SampleService    : fallbak
2021-10-11 14:29:17.916  INFO 25662 --- [nio-8080-exec-2] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:29:17.917  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/500
2021-10-11 14:29:18.112 ERROR 25662 --- [nio-8080-exec-2] o.p.wa.sample.cb.sb.r4j.SampleService    : org.springframework.web.client.HttpServerErrorException$InternalServerError 500 INTERNAL SERVER ERROR: [no body]
2021-10-11 14:29:18.112  INFO 25662 --- [nio-8080-exec-2] o.p.wa.sample.cb.sb.r4j.SampleService    : fallbak
2021-10-11 14:29:18.125  INFO 25662 --- [nio-8080-exec-3] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:29:18.125  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/500
2021-10-11 14:29:18.323 ERROR 25662 --- [nio-8080-exec-3] o.p.wa.sample.cb.sb.r4j.SampleService    : org.springframework.web.client.HttpServerErrorException$InternalServerError 500 INTERNAL SERVER ERROR: [no body]
2021-10-11 14:29:18.324  INFO 25662 --- [nio-8080-exec-3] o.p.wa.sample.cb.sb.r4j.SampleService    : fallbak
2021-10-11 14:29:18.337  INFO 25662 --- [nio-8080-exec-4] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:29:18.338  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:29:18.623  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:29:18.652  INFO 25662 --- [nio-8080-exec-5] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:29:18.652  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:29:18.846  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:29:18.857  INFO 25662 --- [nio-8080-exec-6] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:29:18.858  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:29:19.052  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:29:19.066  INFO 25662 --- [nio-8080-exec-7] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:29:19.067  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:29:19.265  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:29:19.281  INFO 25662 --- [nio-8080-exec-8] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:29:19.281  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:29:19.473  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:29:19.489  INFO 25662 --- [nio-8080-exec-9] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:29:19.490  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:29:19.690  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:29:19.700  INFO 25662 --- [io-8080-exec-10] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:29:19.700  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:29:19.895  INFO 25662 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:29:19.921  INFO 25662 --- [nio-8080-exec-1] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:29:19.927 ERROR 25662 --- [nio-8080-exec-1] o.p.wa.sample.cb.sb.r4j.SampleService    : io.github.resilience4j.circuitbreaker.CallNotPermittedException CircuitBreaker 'myconfig1' is OPEN and does not permit further calls
2021-10-11 14:29:19.927  INFO 25662 --- [nio-8080-exec-1] o.p.wa.sample.cb.sb.r4j.SampleService    : fallbak

5秒以上待機させると、HALF OPEN 状態になり、外部サービス呼び出しができるようになります。HALF OPEN 中に外部サービス呼び出しを失敗させ、再度 OPEN に遷移します。

2021-10-11 14:37:48.044  INFO 26855 --- [nio-8080-exec-2] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:37:48.046  INFO 26855 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/500
2021-10-11 14:37:48.428 ERROR 26855 --- [nio-8080-exec-2] o.p.wa.sample.cb.sb.r4j.SampleService    : org.springframework.web.client.HttpServerErrorException$InternalServerError 500 INTERNAL SERVER ERROR: [no body]
2021-10-11 14:37:48.429  INFO 26855 --- [nio-8080-exec-2] o.p.wa.sample.cb.sb.r4j.SampleService    : fallbak
2021-10-11 14:37:48.441  INFO 26855 --- [nio-8080-exec-3] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:37:48.441  INFO 26855 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/500
2021-10-11 14:37:48.637 ERROR 26855 --- [nio-8080-exec-3] o.p.wa.sample.cb.sb.r4j.SampleService    : org.springframework.web.client.HttpServerErrorException$InternalServerError 500 INTERNAL SERVER ERROR: [no body]
2021-10-11 14:37:48.638  INFO 26855 --- [nio-8080-exec-3] o.p.wa.sample.cb.sb.r4j.SampleService    : fallbak
2021-10-11 14:37:48.651  INFO 26855 --- [nio-8080-exec-4] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:37:48.651  INFO 26855 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:37:48.843  INFO 26855 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:37:48.852  INFO 26855 --- [nio-8080-exec-5] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:37:48.853  INFO 26855 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:37:49.043  INFO 26855 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:37:49.057  INFO 26855 --- [nio-8080-exec-6] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:37:49.058  INFO 26855 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/500
2021-10-11 14:37:49.255 ERROR 26855 --- [nio-8080-exec-6] o.p.wa.sample.cb.sb.r4j.SampleService    : org.springframework.web.client.HttpServerErrorException$InternalServerError 500 INTERNAL SERVER ERROR: [no body]
2021-10-11 14:37:49.255  INFO 26855 --- [nio-8080-exec-6] o.p.wa.sample.cb.sb.r4j.SampleService    : fallbak
2021-10-11 14:37:49.269  INFO 26855 --- [nio-8080-exec-7] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:37:49.270 ERROR 26855 --- [nio-8080-exec-7] o.p.wa.sample.cb.sb.r4j.SampleService    : io.github.resilience4j.circuitbreaker.CallNotPermittedException CircuitBreaker 'myconfig1' is OPEN and does not permit further calls
2021-10-11 14:37:49.270  INFO 26855 --- [nio-8080-exec-7] o.p.wa.sample.cb.sb.r4j.SampleService    : fallbak

再度5秒以上待機させ、HALF OPEN 状態にした後、HALF OPEN 中の失敗率が閾値以下ならば CLOSED に遷移します。

2021-10-11 14:44:19.765  INFO 27061 --- [nio-8080-exec-9] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:44:19.766  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/500
2021-10-11 14:44:20.159 ERROR 27061 --- [nio-8080-exec-9] o.p.wa.sample.cb.sb.r4j.SampleService    : org.springframework.web.client.HttpServerErrorException$InternalServerError 500 INTERNAL SERVER ERROR: [no body]
2021-10-11 14:44:20.159  INFO 27061 --- [nio-8080-exec-9] o.p.wa.sample.cb.sb.r4j.SampleService    : fallbak
2021-10-11 14:44:20.168  INFO 27061 --- [io-8080-exec-10] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:44:20.169  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:44:20.350  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:44:20.364  INFO 27061 --- [nio-8080-exec-1] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:44:20.365  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:44:20.555  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:44:20.571  INFO 27061 --- [nio-8080-exec-2] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:44:20.571  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:44:20.760  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:44:20.770  INFO 27061 --- [nio-8080-exec-3] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:44:20.770  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:44:20.953  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:44:20.964  INFO 27061 --- [nio-8080-exec-4] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:44:20.964  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:44:21.145  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:44:21.156  INFO 27061 --- [nio-8080-exec-5] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:44:21.156  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:44:21.340  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success
2021-10-11 14:44:21.353  INFO 27061 --- [nio-8080-exec-6] o.p.w.sample.cb.sb.r4j.SampleController  : test1
2021-10-11 14:44:21.353  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : request : http://httpbin.org/status/200
2021-10-11 14:44:21.535  INFO 27061 --- [pool-1-thread-1] o.p.wa.sample.cb.sb.r4j.SampleService    : success

本サンプルでは、内部の状態を確認できないので、挙動から判断しています。

参考リンク

CircuitBreaker
Spring Cloud Circuit Breaker とは？ - リファレンスドキュメント

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README.md

README.md

Spring Boot + Spring Cloud CircutBreaker Resilience4j

概要

前提条件

依存ライブラリ

ビルドおよび実行方法

サンプルの説明

アプリケーションへの操作

CLOSED -> OPEN

参考リンク

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README.md

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README.md

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Spring Boot + Spring Cloud CircutBreaker Resilience4j

概要

前提条件

依存ライブラリ

ビルドおよび実行方法

サンプルの説明

アプリケーションへの操作

CLOSED -> OPEN

参考リンク