BAEL-3649 Quick Guide to Spring Cloud Circuit Breaker (#8819)

2020-04-09 10:30:04 +03:00
parent f9ac384b85
commit 88cc732dc7
6 changed files with 201 additions and 0 deletions
@@ -0,0 +1,40 @@
+package com.baeldung.circuitbreaker;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.cloud.client.circuitbreaker.CircuitBreaker;
+import org.springframework.cloud.client.circuitbreaker.CircuitBreakerFactory;
+import org.springframework.stereotype.Service;
+import org.springframework.web.client.RestTemplate;
+
+import java.nio.file.Files;
+import java.nio.file.Paths;
+
+@Service
+public class AlbumService {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(AlbumService.class);
+
+    @Autowired
+    private CircuitBreakerFactory circuitBreakerFactory;
+
+    private RestTemplate restTemplate = new RestTemplate();
+
+    public String getAlbumList() {
+        CircuitBreaker circuitBreaker = circuitBreakerFactory.create("circuitbreaker");
+        String url = "https://jsonplaceholder.typicode.com/albums";
+
+        return circuitBreaker.run(() -> restTemplate.getForObject(url, String.class), throwable -> getDefaultAlbumList());
+    }
+
+    private String getDefaultAlbumList() {
+        try {
+            return new String(Files.readAllBytes(Paths.get(getClass().getClassLoader().getResource("fallback-album-list.json").toURI())));
+        } catch (Exception e) {
+            LOGGER.error("error occurred while reading the file", e);
+        }
+        return null;
+    }
+
+}
@@ -0,0 +1,18 @@
+package com.baeldung.circuitbreaker;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class Controller {
+
+    @Autowired
+    private AlbumService service;
+
+    @GetMapping("/albums")
+    public String albums() {
+        return service.getAlbumList();
+    }
+
+}
@@ -0,0 +1,71 @@
+package com.baeldung.circuitbreaker;
+
+import io.github.resilience4j.circuitbreaker.CircuitBreakerConfig;
+import io.github.resilience4j.timelimiter.TimeLimiterConfig;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.circuitbreaker.resilience4j.Resilience4JCircuitBreakerFactory;
+import org.springframework.cloud.circuitbreaker.resilience4j.Resilience4JConfigBuilder;
+import org.springframework.cloud.client.circuitbreaker.Customizer;
+import org.springframework.context.annotation.Bean;
+
+import java.time.Duration;
+
+@SpringBootApplication
+public class SpringApp {
+
+    public static void main(String[] args) {
+        SpringApplication.run(SpringApp.class, args);
+    }
+
+    @Bean
+    public Customizer<Resilience4JCircuitBreakerFactory> globalCustomConfiguration() {
+        TimeLimiterConfig timeLimiterConfig = TimeLimiterConfig.custom()
+                .timeoutDuration(Duration.ofSeconds(4))
+                .build();
+        CircuitBreakerConfig circuitBreakerConfig = CircuitBreakerConfig.custom()
+                .failureRateThreshold(50)
+                .waitDurationInOpenState(Duration.ofMillis(1000))
+                .slidingWindowSize(2)
+                .build();
+
+        return factory -> factory.configureDefault(id -> new Resilience4JConfigBuilder(id)
+                .timeLimiterConfig(timeLimiterConfig)
+                .circuitBreakerConfig(circuitBreakerConfig)
+                .build());
+    }
+
+    @Bean
+    public Customizer<Resilience4JCircuitBreakerFactory> specificCustomConfiguration1() {
+
+        TimeLimiterConfig timeLimiterConfig = TimeLimiterConfig.custom()
+                .timeoutDuration(Duration.ofSeconds(4))
+                .build();
+        CircuitBreakerConfig circuitBreakerConfig = CircuitBreakerConfig.custom()
+                .failureRateThreshold(50)
+                .waitDurationInOpenState(Duration.ofMillis(1000))
+                .slidingWindowSize(2)
+                .build();
+
+        return factory -> factory.configure(builder -> builder.circuitBreakerConfig(circuitBreakerConfig)
+                .timeLimiterConfig(timeLimiterConfig).build(), "circuitBreaker");
+    }
+
+    @Bean
+    public Customizer<Resilience4JCircuitBreakerFactory> specificCustomConfiguration2() {
+
+        TimeLimiterConfig timeLimiterConfig = TimeLimiterConfig.custom()
+                .timeoutDuration(Duration.ofSeconds(4))
+                .build();
+        CircuitBreakerConfig circuitBreakerConfig = CircuitBreakerConfig.custom()
+                .failureRateThreshold(50)
+                .waitDurationInOpenState(Duration.ofMillis(1000))
+                .slidingWindowSize(2)
+                .build();
+
+        return factory -> factory.configure(builder -> builder.circuitBreakerConfig(circuitBreakerConfig)
+                        .timeLimiterConfig(timeLimiterConfig).build(),
+                "circuitBreaker1", "circuitBreaker2", "circuitBreaker3");
+    }
+
+}
@@ -0,0 +1,12 @@
+[
+  {
+    "userId": 1,
+    "id": 1,
+    "title": "quidem molestiae enim"
+  },
+  {
+    "userId": 1,
+    "id": 2,
+    "title": "sunt qui excepturi placeat culpa"
+  }
+]