深入学习spring cloud gateway 限流熔断

## spring cloud依赖
<parent>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-parent</artifactId>
   <version>2.2.1.RELEASE</version>
</parent>

<properties>
   <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
   <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
   <java.version>11</java.version>
   <spring-cloud.version>Hoxton.RC2</spring-cloud.version>
</properties>

<dependencyManagement>
   <dependencies>
      <dependency>
         <groupId>org.springframework.cloud</groupId>
         <artifactId>spring-cloud-dependencies</artifactId>
         <version>${spring-cloud.version}</version>
         <type>pom</type>
         <scope>import</scope>
      </dependency>
   </dependencies>
</dependencyManagement>

## gateway 依赖
<dependency>
   <groupId>org.springframework.cloud</groupId>
   <artifactId>spring-cloud-starter-gateway</artifactId>
</dependency>
<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-data-redis-reactive</artifactId>
</dependency>
<dependency>
   <groupId>org.projectlombok</groupId>
   <artifactId>lombok</artifactId>
</dependency>
<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-test</artifactId>
   <scope>test</scope>
</dependency>
<dependency>
   <groupId>org.testcontainers</groupId>
   <artifactId>mockserver</artifactId>
   <version>1.12.3</version>
   <scope>test</scope>
</dependency>
<dependency>
   <groupId>org.mock-server</groupId>
   <artifactId>mockserver-client-java</artifactId>
   <version>3.10.8</version>
   <scope>test</scope>
</dependency>
<dependency>
   <groupId>com.carrotsearch</groupId>
   <artifactId>junit-benchmarks</artifactId>
   <version>0.7.2</version>
   <scope>test</scope>
</dependency>

@Bean
KeyResolver userKeyResolver() {
 return exchange -> Mono.just(exchange.getRequest().getQueryParams().getFirst("userId"));
}

@Bean
KeyResolver apiKeyResolver() {
 return exchange -> Mono.just(exchange.getRequest().getPath().value());
}

@SpringBootApplication
public class GatewayApplication {

   public static void main(String[] args) {
      SpringApplication.run(GatewayApplication.class, args);
   }

   @Bean
   KeyResolver userKeyResolver() {
      return exchange -> Mono.just("1");
   }
}

server:
  port: ${PORT:8085}

spring:
  application:
    name: gateway-service
  redis:
    host: localhost
    port: 6379
  cloud:
    gateway:
      routes:
      - id: account-service
        uri: http://localhost:8091
        predicates:
        - Path=/account/**
        filters:
        - RewritePath=/account/(?.*), /$\{path}
      - name: RequestRateLimiter
          args:
            redis-rate-limiter.replenishRate: 10
            redis-rate-limiter.burstCapacity: 20

// routeId也就是我们的服务路由id，id就是限流的key
public Mono<Response> isAllowed(String routeId, String id) {
 // 会判断RedisRateLimiter是否初始化了
 if (!this.initialized.get()) {
  throw new IllegalStateException("RedisRateLimiter is not initialized");
 }
 // 获取routeId对应的限流配置
 Config routeConfig = getConfig().getOrDefault(routeId, defaultConfig);
 
 if (routeConfig == null) {
  throw new IllegalArgumentException("No Configuration found for route " + routeId);
 }
 
 // 允许用户每秒做多少次请求
 int replenishRate = routeConfig.getReplenishRate();
 
 // 令牌桶的容量，允许在一秒钟内完成的最大请求数
 int burstCapacity = routeConfig.getBurstCapacity();
 
 try {
  // 限流key的名称（request_rate_limiter.{localhost}.timestamp，request_rate_limiter.{localhost}.tokens）
  List<String> keys = geTKEys(id);
 
 
  // The arguments to the lua script. time() returns unixtime in seconds.
  List<String> scriptArgs = Arrays.asList(replenishRate + "", burstCapacity + "",
    Instant.now().getEpochSecond() + "", "1");
  // allowed, tokens_left = redis.eval(SCRIPT, keys, args)
  // 执行LUA脚本
  Flux<List<Long>> flux = this.redisTemplate.execute(this.script, keys, scriptArgs);
    // .log("redisratelimiter", Level.FINER);
  return flux.onErrorResume(throwable -> Flux.just(Arrays.asList(1L, -1L)))
    .reduce(new ArrayList<Long>(), (longs, l) -> {
     longs.addAll(l);
     return longs;
    }) .map(results -> {
     boolean allowed = results.get(0) == 1L;
     Long tokensLeft = results.get(1);
 
     Response response = new Response(allowed, getHeaders(routeConfig, tokensLeft));
 
     if (log.isDebugEnabled()) {
      log.debug("response: " + response);
     }
     return response;
    });
 }
 catch (Exception e) {
  log.error("Error determining if user allowed from redis", e);
 }
 return Mono.just(new Response(true, getHeaders(routeConfig, -1L)));
}

@SpringBootTest(WEBEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT)
@RunWith(SpringRunner.class)
public class GatewayRateLimiterTest {

    private static final Logger LOGGER = LoggerFactory.getLogger(GatewayRateLimiterTest.class);

    @Rule
    public TestRule benchmarkRun = new BenchmarkRule();

    @ClassRule
    public static MockServerContainer mockServer = new MockServerContainer();
    @ClassRule
    public static GenericContainer redis = new GenericContainer("redis:5.0.6").withExposedPorts(6379);

    @Autowired
    TestRestTemplate template;

    @BeforeClass
    public static void init() {

        System.setProperty("spring.cloud.gateway.routes[0].id", "account-service");
        System.setProperty("spring.cloud.gateway.routes[0].uri", "http://localhost:" + mockServer.getServerPort());
        System.setProperty("spring.cloud.gateway.routes[0].predicates[0]", "Path=/account/**");
        System.setProperty("spring.cloud.gateway.routes[0].filters[0]", "RewritePath=/account/(?<path>.*), /$\\{path}");
        System.setProperty("spring.cloud.gateway.routes[0].filters[1].name", "RequestRateLimiter");
        System.setProperty("spring.cloud.gateway.routes[0].filters[1].args.redis-rate-limiter.replenishRate", "10");
        System.setProperty("spring.cloud.gateway.routes[0].filters[1].args.redis-rate-limiter.burstCapacity", "20");
        System.setProperty("spring.redis.host", "localhost");
        System.setProperty("spring.redis.port", "" + redis.getMappedPort(6379));
        new MockServerClient(mockServer.getContainerIpAddress(), mockServer.getServerPort())
                .when(HttpRequest.request()
                        .withPath("/1"))
                .respond(response()
                        .withBody("{\"id\":1,\"number\":\"1234567890\"}")
                        .withHeader("Content-Type", "application/JSON"));
    }

    @Test
    @BenchmarkOptions(warmupRounds = 0, concurrency = 6, benchmarkRounds = 600)
    public void testAccountService() {
        ResponseEntity<Account> r = template.exchange("/account/{id}", HttpMethod.GET, null, Account.class, 1);
        LOGGER.info("Received: status->{}, payload->{}, remaining->{}", r.getStatusCodeValue(), r.getBody(), r.getHeaders().get("X-RateLimit-Remaining"));
//  Assert.assertEquals(200, r.getStatusCodeValue());
//  Assert.assertNotNull(r.getBody());
//  Assert.assertEquals(Integer.valueOf(1), r.getBody().getId());
//  Assert.assertEquals("1234567890", r.getBody().getNumber());
    }
}

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

@Bean
public Customizer<ReactiveResilience4JCircuitBreakerFactory> defaultCustomizer() {
   return factory -> factory.configureDefault(id -> new Resilience4JConfigBuilder(id)
      .circuitBreakerConfig(CircuitBreakerConfig.custom()
          //统计失败率的请求总数
         .slidingwindowsize(5) 
         //在半开状态下请求的次数
         .permittedNumberOfCallsInHalfOpenState(5)
         //断路器打开的成功率
         .failureRateThreshold(50.0F)
         //断路器打开的周期
         .waitDurationInOpenState(Duration.ofMillis(30))
         //属于慢请求的周期
         .slowCallDurationThreshold(Duration.ofMillis(200))
        //慢请求打开断路器的成功率
         .slowCallRateThreshold(50.0F)
         .build())
      .timeLimiterConfig(TimeLimiterConfig.custom().timeoutDuration(Duration.ofMillis(200)).build()).build());
}

    @Bean
    public Customizer<ReactiveResilience4JCircuitBreakerFactory> defaultCustomizer() {
        return factory -> factory.configureDefault(id -> new Resilience4JConfigBuilder(id)
    .circuitBreakerConfig(CircuitBreakerConfig.ofDefaults())
                .circuitBreakerConfig(CircuitBreakerConfig.custom()
                        .slowCallDurationThreshold(Duration.ofMillis(200))
                        .build())
                .timeLimiterConfig(TimeLimiterConfig.custom().timeoutDuration(Duration.ofMillis(200)).build())
                .build());
    }

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT)
@RunWith(SpringRunner.class)
public class GatewayCircuitBreakerTest {


    private static final Logger LOGGER = LoggerFactory.getLogger(GatewayRateLimiterTest.class);

    @Rule
    public TestRule benchmarkRun = new BenchmarkRule();

    @ClassRule
    public static MockServerContainer mockServer = new MockServerContainer();

    @Autowired
    TestRestTemplate template;
    final Random random = new Random();
    int i = 0;

    @BeforeClass
    public static void init() {
        System.setProperty("logging.level.org.springframework.cloud.gateway.filter.factory", "TRACE");
        System.setProperty("spring.cloud.gateway.routes[0].id", "account-service");
        System.setProperty("spring.cloud.gateway.routes[0].uri", "http://localhost:" + mockServer.getServerPort());
        System.setProperty("spring.cloud.gateway.routes[0].predicates[0]", "Path=/account/**");
        System.setProperty("spring.cloud.gateway.routes[0].filters[0]", "RewritePath=/account/(?<path>.*), /$\\{path}");
        System.setProperty("spring.cloud.gateway.routes[0].filters[1].name", "CircuitBreaker");
        System.setProperty("spring.cloud.gateway.routes[0].filters[1].args.name", "exampleSlowCircuitBreaker");
//        System.setProperty("spring.cloud.gateway.routes[0].filters[1].args.slowCallDurationThreshold", "100");
//        System.setProperty("spring.cloud.gateway.routes[0].filters[1].args.slowCallRateThreshold", "9.0F");
//        System.setProperty("spring.cloud.gateway.routes[0].filters[1].args.fallbackUri", "forward:/fallback/account");
        MockServerClient client = new MockServerClient(mockServer.getContainerIpAddress(), mockServer.getServerPort());
        client.when(HttpRequest.request()
                .withPath("/1"))
                .respond(response()
                        .withBody("{\"id\":1,\"number\":\"1234567890\"}")
                        .withHeader("Content-Type", "application/json"));
//        client.when(HttpRequest.request()
//                .withPath("/2"), Times.exactly(3))
//    .respond(response()
//                        .withBody("{\"id\":2,\"number\":\"1\"}")
//                        .withDelay(TimeUnit.SECONDS, 1000)
//                        .withHeader("Content-Type", "application/json"));
        client.when(HttpRequest.request()
                .withPath("/2"))
                .respond(response()
                        .withBody("{\"id\":2,\"number\":\"1234567891\"}")
                        .withDelay(TimeUnit.SECONDS, 200)
                        .withHeader("Content-Type", "application/json"));
    }

    @Test
    @BenchmarkOptions(warmupRounds = 0, concurrency = 1, benchmarkRounds = 600)
    public void testAccountService() {
        int gen = 1 + (i++ % 2);
        ResponseEntity<Account> r = template.exchange("/account/{id}", HttpMethod.GET, null, Account.class, gen);
        LOGGER.info("{}. Received: status->{}, payload->{}, call->{}", i, r.getStatusCodeValue(), r.getBody(), gen);
    }
}

     @BeforeClass
    public static void init() {
        System.setProperty("logging.level.org.springframework.cloud.gateway.filter.factory", "TRACE");
        System.setProperty("spring.cloud.gateway.routes[0].id", "account-service");
        System.setProperty("spring.cloud.gateway.routes[0].uri", "http://localhost:" + mockServer.getServerPort());
        System.setProperty("spring.cloud.gateway.routes[0].predicates[0]", "Path=/account/**");
        System.setProperty("spring.cloud.gateway.routes[0].filters[0]", "RewritePath=/account/(?<path>.*), /$\\{path}");
        System.setProperty("spring.cloud.gateway.routes[0].filters[1].name", "CircuitBreaker");
        System.setProperty("spring.cloud.gateway.routes[0].filters[1].args.name", "exampleSlowCircuitBreaker");
//        System.setProperty("spring.cloud.gateway.routes[0].filters[1].args.slowCallDurationThreshold", "100");
//        System.setProperty("spring.cloud.gateway.routes[0].filters[1].args.slowCallRateThreshold", "9.0F");
        System.setProperty("spring.cloud.gateway.routes[0].filters[1].args.fallbackUri", "forward:/fallback/account");
        MockServerClient client = new MockServerClient(mockServer.getContainerIpAddress(), mockServer.getServerPort());
        client.when(HttpRequest.request()
                .withPath("/1"))
                .respond(response()
                        .withBody("{\"id\":1,\"number\":\"1234567890\"}")
                        .withHeader("Content-Type", "application/json"));
        client.when(HttpRequest.request()
                .withPath("/2"), Times.exactly(3))
    .respond(response()
                        .withBody("{\"id\":2,\"number\":\"1\"}")
                        .withDelay(TimeUnit.SECONDS, 1000)
                        .withHeader("Content-Type", "application/json"));
        client.when(HttpRequest.request()
                .withPath("/2"))
                .respond(response()
                        .withBody("{\"id\":2,\"number\":\"1234567891\"}")
//                        .withDelay(TimeUnit.SECONDS, 200)
                        .withHeader("Content-Type", "application/json"));
    }

@RestController
@RequestMapping("/fallback")
public class GatewayFallback {

    @GetMapping("/account")
    public Account getAccount() {
        Account a = new Account();
        a.setId(2);
        a.setNumber("123456");
        return a;
    }

}