BAEL-5798: Guide to Resilience4j with Spring Boot (#12854)

Co-authored-by: Tapan Avasthi <tavasthi@Tapans-MacBook-Air.local>
2022-10-17 08:03:41 +05:30
parent 6da922c20a
commit 58b522ec56
8 changed files with 359 additions and 0 deletions
@@ -0,0 +1,135 @@
+package com.baeldung.resilientapp;
+
+import static com.github.tomakehurst.wiremock.client.WireMock.getRequestedFor;
+import static com.github.tomakehurst.wiremock.client.WireMock.ok;
+import static com.github.tomakehurst.wiremock.client.WireMock.serverError;
+
+import static com.github.tomakehurst.wiremock.client.WireMock.urlEqualTo;
+import static org.assertj.core.api.AssertionsForClassTypes.assertThat;
+import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import static org.springframework.http.HttpStatus.BANDWIDTH_LIMIT_EXCEEDED;
+import static org.springframework.http.HttpStatus.OK;
+import static org.springframework.http.HttpStatus.TOO_MANY_REQUESTS;
+
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import java.util.stream.IntStream;
+
+import org.junit.Assert;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+
+import com.github.tomakehurst.wiremock.client.WireMock;
+import com.github.tomakehurst.wiremock.core.WireMockConfiguration;
+import com.github.tomakehurst.wiremock.junit5.WireMockExtension;
+
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+class ResilientAppControllerUnitTest {
+
+    @RegisterExtension
+    static WireMockExtension EXTERNAL_SERVICE = WireMockExtension.newInstance()
+        .options(WireMockConfiguration.wireMockConfig()
+            .port(9090))
+        .build();
+
+    @Autowired
+    private TestRestTemplate restTemplate;
+
+    @Test
+    public void testCircuitBreaker() {
+        EXTERNAL_SERVICE.stubFor(WireMock.get("/api/external")
+            .willReturn(serverError()));
+
+        IntStream.rangeClosed(1, 5)
+            .forEach(i -> {
+                ResponseEntity<String> response = restTemplate.getForEntity("/api/circuit-breaker", String.class);
+                assertThat(response.getStatusCode()).isEqualTo(HttpStatus.INTERNAL_SERVER_ERROR);
+            });
+
+        IntStream.rangeClosed(1, 5)
+            .forEach(i -> {
+                ResponseEntity<String> response = restTemplate.getForEntity("/api/circuit-breaker", String.class);
+                assertThat(response.getStatusCode()).isEqualTo(HttpStatus.SERVICE_UNAVAILABLE);
+            });
+
+        EXTERNAL_SERVICE.verify(5, getRequestedFor(urlEqualTo("/api/external")));
+    }
+
+    @Test
+    public void testRetry() {
+        EXTERNAL_SERVICE.stubFor(WireMock.get("/api/external")
+            .willReturn(ok()));
+        ResponseEntity<String> response1 = restTemplate.getForEntity("/api/retry", String.class);
+        EXTERNAL_SERVICE.verify(1, getRequestedFor(urlEqualTo("/api/external")));
+
+        EXTERNAL_SERVICE.resetRequests();
+
+        EXTERNAL_SERVICE.stubFor(WireMock.get("/api/external")
+            .willReturn(serverError()));
+        ResponseEntity<String> response2 = restTemplate.getForEntity("/api/retry", String.class);
+        Assert.assertEquals(response2.getBody(), "all retries have exhausted");
+        EXTERNAL_SERVICE.verify(3, getRequestedFor(urlEqualTo("/api/external")));
+    }
+
+    @Test
+    public void testBulkhead() {
+        EXTERNAL_SERVICE.stubFor(WireMock.get("/api/external")
+            .willReturn(ok()));
+        Map<Integer, Integer> responseStatusCount = new ConcurrentHashMap<>();
+
+        IntStream.rangeClosed(1, 5)
+            .parallel()
+            .forEach(i -> {
+                ResponseEntity<String> response = restTemplate.getForEntity("/api/bulkhead", String.class);
+                int statusCode = response.getStatusCodeValue();
+                responseStatusCount.put(statusCode, responseStatusCount.getOrDefault(statusCode, 0) + 1);
+            });
+
+        assertEquals(2, responseStatusCount.keySet()
+            .size());
+        assertTrue(responseStatusCount.containsKey(BANDWIDTH_LIMIT_EXCEEDED.value()));
+        assertTrue(responseStatusCount.containsKey(OK.value()));
+        EXTERNAL_SERVICE.verify(3, getRequestedFor(urlEqualTo("/api/external")));
+    }
+
+    @Test
+    public void testTimeLimiter() {
+        EXTERNAL_SERVICE.stubFor(WireMock.get("/api/external")
+            .willReturn(ok()));
+        ResponseEntity<String> response = restTemplate.getForEntity("/api/time-limiter", String.class);
+
+        assertThat(response.getStatusCode()).isEqualTo(HttpStatus.REQUEST_TIMEOUT);
+        EXTERNAL_SERVICE.verify(1, getRequestedFor(urlEqualTo("/api/external")));
+    }
+
+    @Test
+    public void testRatelimiter() {
+        EXTERNAL_SERVICE.stubFor(WireMock.get("/api/external")
+            .willReturn(ok()));
+        Map<Integer, Integer> responseStatusCount = new ConcurrentHashMap<>();
+
+        IntStream.rangeClosed(1, 50)
+            .parallel()
+            .forEach(i -> {
+                ResponseEntity<String> response = restTemplate.getForEntity("/api/rate-limiter", String.class);
+                int statusCode = response.getStatusCodeValue();
+                responseStatusCount.put(statusCode, responseStatusCount.getOrDefault(statusCode, 0) + 1);
+            });
+
+        assertEquals(2, responseStatusCount.keySet()
+            .size());
+        assertTrue(responseStatusCount.containsKey(TOO_MANY_REQUESTS.value()));
+        assertTrue(responseStatusCount.containsKey(OK.value()));
+        EXTERNAL_SERVICE.verify(5, getRequestedFor(urlEqualTo("/api/external")));
+    }
+}