Replace Hystrix by Spring Cloud Circuit Breaker and Resilience4j #117

README.md

@@ -2,7 +2,9 @@
 
 [![Build Status](https://travis-ci.org/spring-petclinic/spring-petclinic-microservices.svg?branch=master)](https://travis-ci.org/spring-petclinic/spring-petclinic-microservices/) [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 
-This microservices branch was initially derived from [AngularJS version](https://github.com/spring-petclinic/spring-petclinic-angular1) to demonstrate how to split sample Spring application into [microservices](http://www.martinfowler.com/articles/microservices.html). To achieve that goal we used [Spring Cloud Netflix](https://github.com/spring-cloud/spring-cloud-netflix) technology stack.
+This microservices branch was initially derived from [AngularJS version](https://github.com/spring-petclinic/spring-petclinic-angular1) to demonstrate how to split sample Spring application into [microservices](http://www.martinfowler.com/articles/microservices.html).
+To achieve that goal we use Spring Cloud Gateway, Spring Cloud Circuit Breaker, Spring Cloud Config, Spring Cloud Sleuth, Resilience4j, Micrometer 
+and the Eureka Service Discovery from the [Spring Cloud Netflix](https://github.com/spring-cloud/spring-cloud-netflix) technology stack.
 
 ## Starting services locally without Docker
 
@@ -17,10 +19,6 @@ If everything goes well, you can access the following services at given location
 * Admin Server (Spring Boot Admin) - http://localhost:9090
 * Grafana Dashboards - http://localhost:3000
 * Prometheus - http://localhost:9091
-* Hystrix Dashboard for Circuit Breaker pattern - http://localhost:7979 - On the home page is a form where you can enter 
-the URL for an event stream to monitor, for example the `api-gateway` service running locally: `http://localhost:8080/actuator/hystrix.stream` 
-or running into docker: `http://api-gateway:8080/actuator/hystrix.stream`
-
 
 You can tell Config Server to use your local Git repository by using `native` Spring profile and setting
 `GIT_REPO` environment variable, for example:
@@ -131,7 +129,7 @@ All those three REST controllers `OwnerResource`, `PetResource` and `VisitResour
 | Service Discovery               | [Eureka server](spring-petclinic-discovery-server) and [Service discovery client](spring-petclinic-vets-service/src/main/java/org/springframework/samples/petclinic/vets/VetsServiceApplication.java) |
 | API Gateway                     | [Spring Cloud Gateway starter](spring-petclinic-api-gateway/pom.xml) and [Routing configuration](/spring-petclinic-api-gateway/src/main/resources/application.yml) |
 | Docker Compose                  | [Spring Boot with Docker guide](https://spring.io/guides/gs/spring-boot-docker/) and [docker-compose file](docker-compose.yml) |
-| Circuit Breaker                 | [Hystrix fallback method](spring-petclinic-api-gateway/src/main/java/org/springframework/samples/petclinic/api/application/VisitsServiceClient.java)  |
+| Circuit Breaker                 | [Resilience4j fallback method](spring-petclinic-api-gateway/src/main/java/org/springframework/samples/petclinic/api/boundary/web/ApiGatewayController.java)  |
 | Grafana / Prometheus Monitoring | [Micrometer implementation](https://micrometer.io/), [Spring Boot Actuator Production Ready Metrics] |
 
  Front-end module  | Files |

docker-compose.yml

@@ -82,17 +82,6 @@ services:
     ports:
      - 9090:9090
 
-  hystrix-dashboard:
-    image: springcommunity/spring-petclinic-hystrix-dashboard
-    container_name: hystrix-dashboard
-    mem_limit: 512M
-    depends_on:
-     - config-server
-     - discovery-server
-    entrypoint: ["./dockerize","-wait=tcp://discovery-server:8761","-timeout=60s","--","java", "-XX:+UnlockExperimentalVMOptions", "-XX:+UseCGroupMemoryLimitForHeap", "-Djava.security.egd=file:/dev/./urandom","-jar","/app.jar"]
-    ports:
-     - 7979:7979
-
   ## Grafana / Prometheus
 
   grafana-server:

pom.xml

@@ -23,7 +23,6 @@
         <module>spring-petclinic-config-server</module>
         <module>spring-petclinic-discovery-server</module>
         <module>spring-petclinic-api-gateway</module>
-        <module>spring-petclinic-hystrix-dashboard</module>
     </modules>
 
     <properties>

spring-petclinic-api-gateway/pom.xml

@@ -53,6 +53,10 @@
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-sleuth-zipkin</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-starter-circuitbreaker-reactor-resilience4j</artifactId>
+        </dependency>
         <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-config</artifactId>
@@ -73,6 +77,10 @@
                     <groupId>com.netflix.ribbon</groupId>
                     <artifactId>ribbon-eureka</artifactId>
                 </exclusion>
+                <exclusion>
+                    <groupId>org.springframework.cloud</groupId>
+                    <artifactId>spring-cloud-netflix-hystrix</artifactId>
+                </exclusion>
             </exclusions>
         </dependency>
         <dependency>
@@ -83,16 +91,6 @@
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-gateway</artifactId>
         </dependency>
-        <dependency>
-            <groupId>org.springframework.cloud</groupId>
-            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
-            <exclusions>
-                <exclusion>
-                    <groupId>org.springframework.cloud</groupId>
-                    <artifactId>spring-cloud-netflix-ribbon</artifactId>
-                </exclusion>
-            </exclusions>
-        </dependency>
 
         <!-- Third parties -->
         <dependency>
@@ -107,6 +105,10 @@
             <groupId>io.micrometer</groupId>
             <artifactId>micrometer-registry-prometheus</artifactId>
         </dependency>
+        <dependency>
+            <groupId>io.github.resilience4j</groupId>
+            <artifactId>resilience4j-micrometer</artifactId>
+        </dependency>
 
         <!-- Webjars -->
         <dependency>

spring-petclinic-api-gateway/src/main/java/org/springframework/samples/petclinic/api/ApiGatewayApplication.java

@@ -15,10 +15,14 @@
  */
 package org.springframework.samples.petclinic.api;
 
+import io.github.resilience4j.circuitbreaker.CircuitBreakerConfig;
+import io.github.resilience4j.timelimiter.TimeLimiterConfig;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
-import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
+import org.springframework.cloud.circuitbreaker.resilience4j.ReactiveResilience4JCircuitBreakerFactory;
+import org.springframework.cloud.circuitbreaker.resilience4j.Resilience4JConfigBuilder;
+import org.springframework.cloud.client.circuitbreaker.Customizer;
 import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
 import org.springframework.cloud.client.loadbalancer.LoadBalanced;
 import org.springframework.context.annotation.Bean;
@@ -32,12 +36,13 @@
 import org.springframework.web.reactive.function.server.RouterFunctions;
 import org.springframework.web.reactive.function.server.ServerResponse;
 
+import java.time.Duration;
+
 
 /**
  * @author Maciej Szarlinski
  */
 @EnableDiscoveryClient
-@EnableCircuitBreaker
 @SpringBootApplication
 public class ApiGatewayApplication {
 
@@ -71,4 +76,15 @@ RouterFunction<?> routerFunction() {
                 request -> ServerResponse.ok().contentType(MediaType.TEXT_HTML).bodyValue(indexHtml));
         return router;
     }
+
+    /**
+     * Default Resilience4j circuit breaker configuration
+     */
+    @Bean
+    public Customizer<ReactiveResilience4JCircuitBreakerFactory> defaultCustomizer() {
+        return factory -> factory.configureDefault(id -> new Resilience4JConfigBuilder(id)
+            .circuitBreakerConfig(CircuitBreakerConfig.ofDefaults())
+            .timeLimiterConfig(TimeLimiterConfig.custom().timeoutDuration(Duration.ofSeconds(4)).build())
+            .build());
+    }
 }

spring-petclinic-api-gateway/src/main/java/org/springframework/samples/petclinic/api/application/VisitsServiceClient.java

@@ -16,15 +16,12 @@
 package org.springframework.samples.petclinic.api.application;
 
 import lombok.RequiredArgsConstructor;
-import org.springframework.samples.petclinic.api.dto.VisitDetails;
 import org.springframework.samples.petclinic.api.dto.Visits;
 import org.springframework.stereotype.Component;
 import org.springframework.web.reactive.function.client.WebClient;
 import reactor.core.publisher.Mono;
 
-import java.util.Collections;
 import java.util.List;
-import java.util.Map;
 
 import static java.util.stream.Collectors.joining;
 
@@ -40,7 +37,6 @@ public class VisitsServiceClient {
 
     private final WebClient.Builder webClientBuilder;
 
-    // FIXME HYSTRIX @HystrixCommand(fallbackMethod = "emptyVisitsForPets")
     public Mono<Visits> getVisitsForPets(final List<Integer> petIds) {
         return webClientBuilder.build()
             .get()
@@ -53,10 +49,6 @@ private String joinIds(List<Integer> petIds) {
         return petIds.stream().map(Object::toString).collect(joining(","));
     }
 
-    private Mono<Map<Integer, List<VisitDetails>>> emptyVisitsForPets(Mono<List<Integer>> petIds) {
-        return Mono.just(Collections.emptyMap());
-    }
-
     void setHostname(String hostname) {
         this.hostname = hostname;
     }

spring-petclinic-api-gateway/src/main/java/org/springframework/samples/petclinic/api/boundary/web/ApiGatewayController.java

@@ -16,6 +16,8 @@
 package org.springframework.samples.petclinic.api.boundary.web;
 
 import lombok.RequiredArgsConstructor;
+import org.springframework.cloud.client.circuitbreaker.ReactiveCircuitBreaker;
+import org.springframework.cloud.client.circuitbreaker.ReactiveCircuitBreakerFactory;
 import org.springframework.samples.petclinic.api.application.CustomersServiceClient;
 import org.springframework.samples.petclinic.api.application.VisitsServiceClient;
 import org.springframework.samples.petclinic.api.dto.OwnerDetails;
@@ -41,11 +43,17 @@ public class ApiGatewayController {
 
     private final VisitsServiceClient visitsServiceClient;
 
+    private final ReactiveCircuitBreakerFactory cbFactory;
+
     @GetMapping(value = "owners/{ownerId}")
     public Mono<OwnerDetails> getOwnerDetails(final @PathVariable int ownerId) {
         return customersServiceClient.getOwner(ownerId)
             .flatMap(owner ->
                 visitsServiceClient.getVisitsForPets(owner.getPetIds())
+                    .transform(it -> {
+                        ReactiveCircuitBreaker cb = cbFactory.create("getOwnerDetails");
+                        return cb.run(it, throwable -> emptyVisitsForPets());
+                    })
                     .map(addVisitsToOwner(owner))
             );
 
@@ -62,4 +70,8 @@ private Function<Visits, OwnerDetails> addVisitsToOwner(OwnerDetails owner) {
             return owner;
         };
     }
+
+    private Mono<Visits> emptyVisitsForPets() {
+        return Mono.just(new Visits());
+    }
 }

spring-petclinic-api-gateway/src/main/java/org/springframework/samples/petclinic/api/dto/VisitDetails.java

@@ -15,13 +15,13 @@
  */
 package org.springframework.samples.petclinic.api.dto;
 
+import lombok.Data;
 import lombok.NoArgsConstructor;
-import lombok.Value;
 
 /**
  * @author Maciej Szarlinski
  */
-@Value
+@Data
 @NoArgsConstructor
 public class VisitDetails {
 

spring-petclinic-api-gateway/src/main/java/org/springframework/samples/petclinic/api/dto/Visits.java

@@ -15,6 +15,7 @@
  */
 package org.springframework.samples.petclinic.api.dto;
 
+import java.util.ArrayList;
 import java.util.List;
 
 import lombok.NoArgsConstructor;
@@ -24,9 +25,8 @@
  * @author Maciej Szarlinski
  */
 @Value
-@NoArgsConstructor
 public class Visits {
 
-    private List<VisitDetails> items = null;
+    private List<VisitDetails> items = new ArrayList<>();
 
 }

spring-petclinic-api-gateway/src/test/java/org/springframework/samples/petclinic/api/application/VisitsServiceClientIntegrationTest.java

@@ -47,20 +47,6 @@ void getVisitsForPets_withAvailableVisitsService() {
         assertVisitDescriptionEquals(visits.block(), PET_ID,"test visit");
     }
 
-    /**
-     * Test Hystrix fallback method
-     */
-//    @Test
-//    public void getVisitsForPets_withServerError() {
-//
-//        mockServer.expect(requestTo("http://visits-service/pets/visits?petId=1"))
-//            .andRespond(withServerError());
-//
-//        Map<Integer, List<VisitDetails>> visits = null;
-//        visitsServiceClient.getVisitsForPets(Mono.just(Collections.singletonList(1)));
-//
-//        assertEquals(0, visits.size());
-//    }
 
     private void assertVisitDescriptionEquals(Visits visits, int petId, String description) {
         assertEquals(1, visits.getItems().size());

spring-petclinic-api-gateway/src/test/java/org/springframework/samples/petclinic/api/boundary/web/ApiGatewayControllerTest.java

@@ -0,0 +1,99 @@
+package org.springframework.samples.petclinic.api.boundary.web;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mockito;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.reactive.WebFluxTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.cloud.circuitbreaker.resilience4j.ReactiveResilience4JAutoConfiguration;
+import org.springframework.context.annotation.Import;
+import org.springframework.samples.petclinic.api.application.CustomersServiceClient;
+import org.springframework.samples.petclinic.api.application.VisitsServiceClient;
+import org.springframework.samples.petclinic.api.dto.OwnerDetails;
+import org.springframework.samples.petclinic.api.dto.PetDetails;
+import org.springframework.samples.petclinic.api.dto.VisitDetails;
+import org.springframework.samples.petclinic.api.dto.Visits;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+import org.springframework.test.web.reactive.server.WebTestClient;
+import reactor.core.publisher.Mono;
+
+import java.net.ConnectException;
+import java.util.Collections;
+
+@ExtendWith(SpringExtension.class)
+@WebFluxTest(controllers = ApiGatewayController.class)
+@Import(ReactiveResilience4JAutoConfiguration.class)
+class ApiGatewayControllerTest {
+
+    @MockBean
+    private CustomersServiceClient customersServiceClient;
+
+    @MockBean
+    private VisitsServiceClient visitsServiceClient;
+
+    @Autowired
+    private WebTestClient client;
+
+
+    @Test
+    void getOwnerDetails_withAvailableVisitsService() {
+        OwnerDetails owner = new OwnerDetails();
+        PetDetails cat = new PetDetails();
+        cat.setId(20);
+        cat.setName("Garfield");
+        owner.getPets().add(cat);
+        Mockito
+            .when(customersServiceClient.getOwner(1))
+            .thenReturn(Mono.just(owner));
+
+        Visits visits = new Visits();
+        VisitDetails visit = new VisitDetails();
+        visit.setId(300);
+        visit.setDescription("First visit");
+        visit.setPetId(cat.getId());
+        visits.getItems().add(visit);
+        Mockito
+            .when(visitsServiceClient.getVisitsForPets(Collections.singletonList(cat.getId())))
+            .thenReturn(Mono.just(visits));
+
+        client.get()
+            .uri("/api/gateway/owners/1")
+            .exchange()
+            .expectStatus().isOk()
+            //.expectBody(String.class)
+            //.consumeWith(response ->
+            //    Assertions.assertThat(response.getResponseBody()).isEqualTo("Garfield"));
+            .expectBody()
+            .jsonPath("$.pets[0].name").isEqualTo("Garfield")
+            .jsonPath("$.pets[0].visits[0].description").isEqualTo("First visit");
+    }
+
+    /**
+     * Test Resilience4j fallback method
+     */
+    @Test
+    void getOwnerDetails_withServiceError() {
+        OwnerDetails owner = new OwnerDetails();
+        PetDetails cat = new PetDetails();
+        cat.setId(20);
+        cat.setName("Garfield");
+        owner.getPets().add(cat);
+        Mockito
+            .when(customersServiceClient.getOwner(1))
+            .thenReturn(Mono.just(owner));
+
+        Mockito
+            .when(visitsServiceClient.getVisitsForPets(Collections.singletonList(cat.getId())))
+            .thenReturn(Mono.error(new ConnectException("Simulate error")));
+
+        client.get()
+            .uri("/api/gateway/owners/1")
+            .exchange()
+            .expectStatus().isOk()
+            .expectBody()
+            .jsonPath("$.pets[0].name").isEqualTo("Garfield")
+            .jsonPath("$.pets[0].visits").isEmpty();
+    }
+
+}