Resilience4J Ratelimiter does not limit access of annotated method

Question

I am using the resilience4j-spring-boot2 library (io.github.resilience4j:resilience4j-spring-boot2, version 1.5.0) and Spring Boot version 2.3.1.RELEASE. I created a RateLimiter which should only let one thread execute a certain method every 30 seconds. However, there does not seem to be a boundary (except for configurated number of threads running in the Tomcat server) for threads to call the method.

I implemented a simple Service which waits for a given amount of time and then returns "Hello!":

@RequestMapping("/")
@RestController
public class ResilientService {

    @RateLimiter(name = "hello-rl")
    @GetMapping("/hello/{timeout}")
    public String hello(@PathVariable int timeout) throws InterruptedException {
        Thread.sleep(timeout);
        return "Hello!";
    }

}

And configured the Ratelimiter as follows

resilience4j.ratelimiter:
  instances:
    hello-rl:
      limitForPeriod: 1  # The number of permissions available during one limit refresh period
      limitRefreshPeriod: 30s  # The period of a limit refresh. After each period the rate limiter sets its permissions count back to the limitForPeriod value
      timeoutDuration: 30s  # The default wait time a thread waits for a permission

And I called the service with eight threads:

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
@RunWith(SpringRunner.class)
@Slf4j
public class CircuitBreakerTest {

    @Autowired
    TestRestTemplate testRestTemplate;

    @LocalServerPort
    private int port;

    @Value("${server.address}")
    private String serverAddress;

    @Test
    public void t() throws InterruptedException {
        final ExecutorService executorService = Executors.newFixedThreadPool(8);

        for (int i : IntStream.rangeClosed(1, 8).toArray()) {
            executorService.execute(() -> log.error(callService()));
        }

        executorService.shutdown();
        executorService.awaitTermination(1, TimeUnit.MINUTES);
    }

    private String callService() {
        return testRestTemplate.getForObject(
                "http://" + serverAddress + ":" + port + "/hello/5000",
                String.class
        );
    }

The output is as follows:

2020-08-07 10:41:10,095 ERROR [pool-1-thread-7] CircuitBreakerTest: Hello!
2020-08-07 10:41:10,095 ERROR [pool-1-thread-1] CircuitBreakerTest: Hello!
2020-08-07 10:41:10,095 ERROR [pool-1-thread-8] CircuitBreakerTest: Hello!
2020-08-07 10:41:10,095 ERROR [pool-1-thread-2] CircuitBreakerTest: Hello!
2020-08-07 10:41:10,095 ERROR [pool-1-thread-5] CircuitBreakerTest: Hello!
2020-08-07 10:41:15,104 ERROR [pool-1-thread-3] CircuitBreakerTest: Hello!
2020-08-07 10:41:15,121 ERROR [pool-1-thread-4] CircuitBreakerTest: Hello!
2020-08-07 10:41:15,121 ERROR [pool-1-thread-6] CircuitBreakerTest: Hello!

Only five threads seem to be allowed to execute the method at one time, but I don't know why. The Tomcat server is running with >8 threads. Did I make a mistake? Or am I misunderstanding how the RateLimiter is supposed to work?

Well if you debug it you will see that your properties are ignored and default config is taken into account. But even after I fixed that it still didn't work, so no answer :) — Shadov, Aug 07 '20 at 09:36

score 4 · Answer 1 · answered Aug 07 '20 at 13:41

resilience4j-spring-boot2 uses aspects internally, so it is needed to add the spring-boot-starter-aop dependency to the project for the annotations to work:

        <dependency>
            <!-- for rate limiting -->
            <groupId>io.github.resilience4j</groupId>
            <artifactId>resilience4j-spring-boot2</artifactId>
            <version>${resilience4j.version}</version>
        </dependency>
        <dependency>
            <!-- needed for Resilience4j -->
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>

As stated in the official documentation right at the beginning ("Setup")... totally missed that.

Resilience4J Ratelimiter does not limit access of annotated method

1 Answers1