I am facing a issue with the circuit breaker implementation using Spring Cloud Resilience4j.
Following some tutorial, I have tried to add the necessary dependencies in the project. Also, tried to add the configurations but, still the circuit is not opening and fallback method is not getting called.
For the use case, I am calling an external API from my service and if that external API is down then after few calls I need to enable the circuit breaker.
Please find the code pieces from the different files.
I am a newbie to circuit breaker pattern. Any help will be highly appreciated.
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.5.5</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<java.version>11</java.version>
<spring-cloud.version>2020.0.4</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-circuitbreaker-resilience4j</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-aop</artifactId>
</dependency>
<dependencies>
</project>
Application properties
resilience4j.circuitbreaker.instances.test-api.register-health-indicator=true
resilience4j.circuitbreaker.instances.test-api.minimum-number-of-calls=4
resilience4j.circuitbreaker.instances.test-api.failure-rate-threshold=50
resilience4j.circuitbreaker.instances.test-api.permitted-number-of-calls-in-half-open-state=3
resilience4j.circuitbreaker.instances.test-api.wait-duration-in-open-state=30s
resilience4j.circuitbreaker.instances.test-api.automatic-transition-from-open-to-half-open-enabled=true
resilience4j.circuitbreaker.instances.test-api.record-exceptions=com.testapi.exception.ServiceUnavailableError
Service Class Code Piece
@CircuitBreaker(name = "test-api", fallbackMethod = "storeResponseFallback")
public TestResponse storeResponse(String apiURL, HttpEntity<String> entityrequest) {
TestResponse testResponse = new TestResponse();
Optional<ResponseEntity<TestResponse>> response = Optional.empty();
Future<ResponseEntity<TestResponse>> responseFuture;
ExecutorService executor = Executors.newFixedThreadPool(10);
log.debug("Calling Extrenal API, Request Body: {}", entityrequest.toString());
try {
//Service call returns a future
responseFuture = executor.submit(() -> restTemplate.postForEntity(apiURL, entityrequest, TestResponse.class));
response = Optional.ofNullable(responseFuture.get());
log.info("Got response from external API");
if ((response.isPresent()) && (response.get().hasBody())) {
testResponse = response.get().getBody();
}
} catch (Exception exception) {
log.error("External api call got failed with an error");
Thread.currentThread().interrupt();
throw new ServiceUnavailableError();
}
return testResponse;
}
public TestResponse storeResponseFallback(ServiceUnavailableError ex) {
log.error("Executing Fallback Method For General exceptions");
throw new ServiceUnavailableError();
}
ServiceUnavailableError Java file
@Data
@AllArgsConstructor
@NoArgsConstructor
public class ServiceUnavailableError extends RuntimeException{
private static final long serialVersionUID = 2382122402994502766L;
private String message;
}
