Merge pull request #17574 from pedrolopes9-7/BAEL-8300

BAEL-8300: Using CompletableFuture With Feign Client in Spring Boot

spring-cloud-modules/spring-cloud-openfeign-2/pom.xml

@@ -7,6 +7,18 @@
     <artifactId>spring-cloud-openfeign-2</artifactId>
     <name>spring-cloud-openfeign-2</name>
     <description>OpenFeign project for Spring Boot</description>
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>9</source>
+                    <target>9</target>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
 
     <parent>
         <groupId>com.baeldung.spring.cloud</groupId>

spring-cloud-modules/spring-cloud-openfeign-2/src/main/java/com/baeldung/cloud/openfeign/completablefuturefeignclient/PaymentMethodClient.java

@@ -0,0 +1,13 @@
+package com.baeldung.cloud.openfeign.completablefuturefeignclient;
+
+import org.springframework.cloud.openfeign.FeignClient;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+import org.springframework.web.bind.annotation.RequestParam;
+
+@FeignClient(name = "paymentMethodClient", url = "http://localhost:8083")
+public interface PaymentMethodClient {
+
+    @RequestMapping(method = RequestMethod.GET, value = "/payment_methods")
+    String getAvailablePaymentMethods(@RequestParam(name = "site_id") String siteId);
+}

spring-cloud-modules/spring-cloud-openfeign-2/src/main/java/com/baeldung/cloud/openfeign/completablefuturefeignclient/PurchaseService.java

@@ -0,0 +1,50 @@
+package com.baeldung.cloud.openfeign.completablefuturefeignclient;
+
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+
+import org.springframework.stereotype.Service;
+
+import feign.FeignException;
+import feign.RetryableException;
+
+@Service
+public class PurchaseService {
+
+    private final PaymentMethodClient paymentMethodClient;
+    private final ReportClient reportClient;
+
+    public PurchaseService(PaymentMethodClient paymentMethodClient, ReportClient reportClient) {
+        this.paymentMethodClient = paymentMethodClient;
+        this.reportClient = reportClient;
+    }
+
+    public String executePurchase(String siteId) throws ExecutionException, InterruptedException {
+        CompletableFuture<String> paymentMethodsFuture = CompletableFuture.supplyAsync(() -> paymentMethodClient.getAvailablePaymentMethods(siteId))
+            .orTimeout(400, TimeUnit.MILLISECONDS)
+            .exceptionally(ex -> {
+                if (ex.getCause() instanceof FeignException && ((FeignException) ex.getCause()).status() == 404) {
+                    return "cash";
+                }
+
+                if (ex.getCause() instanceof RetryableException) {
+                    // handle REST timeout
+                    throw new RuntimeException("REST call network timeout!");
+                }
+
+                if (ex instanceof TimeoutException) {
+                    // handle thread timeout
+                    throw new RuntimeException("Thread timeout!", ex);
+                }
+
+                throw new RuntimeException("Unrecoverable error!", ex);
+            });
+
+        CompletableFuture.runAsync(() -> reportClient.sendReport("Purchase Order Report"))
+            .orTimeout(400, TimeUnit.MILLISECONDS);
+
+        return String.format("Purchase executed with payment method %s", paymentMethodsFuture.get());
+    }
+}

spring-cloud-modules/spring-cloud-openfeign-2/src/main/java/com/baeldung/cloud/openfeign/completablefuturefeignclient/ReportClient.java

@@ -0,0 +1,13 @@
+package com.baeldung.cloud.openfeign.completablefuturefeignclient;
+
+import org.springframework.cloud.openfeign.FeignClient;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestMethod;
+
+@FeignClient(name = "reportClient", url = "http://localhost:8083")
+public interface ReportClient {
+
+    @RequestMapping(method = RequestMethod.POST, value = "/reports")
+    void sendReport(@RequestBody String reportRequest);
+}

spring-cloud-modules/spring-cloud-openfeign-2/src/main/resources/application.properties

@@ -7,4 +7,9 @@ spring.main.allow-bean-definition-overriding=true
 logging.level.com.baeldung.cloud.openfeign.client=INFO
 feign.hystrix.enabled=true
 
-spring.cloud.openfeign.client.config.postClient.url=https://jsonplaceholder.typicode.com/posts/
+spring.cloud.openfeign.client.config.postClient.url=https://jsonplaceholder.typicode.com/posts/
+
+feign.client.config.paymentMethodClient.readTimeout: 200
+feign.client.config.paymentMethodClient.connectTimeout: 100
+feign.client.config.reportClient.readTimeout: 200
+feign.client.config.reportClient.connectTimeout: 100

spring-cloud-modules/spring-cloud-openfeign-2/src/test/java/com/baeldung/cloud/openfeign/completablefuturefeignclient/PurchaseServiceIntegrationTest.java

@@ -0,0 +1,94 @@
+package com.baeldung.cloud.openfeign.completablefuturefeignclient;
+
+import com.baeldung.cloud.openfeign.ExampleApplication;
+import com.github.tomakehurst.wiremock.WireMockServer;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Disabled;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.HttpStatus;
+import org.springframework.test.context.junit.jupiter.SpringExtension;
+
+import java.util.concurrent.ExecutionException;
+
+import static com.github.tomakehurst.wiremock.client.WireMock.aResponse;
+import static com.github.tomakehurst.wiremock.client.WireMock.configureFor;
+import static com.github.tomakehurst.wiremock.client.WireMock.get;
+import static com.github.tomakehurst.wiremock.client.WireMock.post;
+import static com.github.tomakehurst.wiremock.client.WireMock.stubFor;
+import static com.github.tomakehurst.wiremock.client.WireMock.urlEqualTo;
+import static org.junit.Assert.*;
+
+@ExtendWith(SpringExtension.class)
+@SpringBootTest(classes = ExampleApplication.class)
+class PurchaseServiceIntegrationTest {
+
+    @Autowired
+    private PurchaseService purchaseService;
+
+    @Autowired
+    private PaymentMethodClient paymentMethodClient;
+
+    @Autowired
+    private ReportClient reportClient;
+
+    private WireMockServer wireMockServer;
+
+    @BeforeEach
+    public void startWireMockServer() {
+        wireMockServer = new WireMockServer(8083);
+        configureFor("localhost", 8083);
+        wireMockServer.start();
+
+        stubFor(post(urlEqualTo("/reports")).willReturn(aResponse().withStatus(HttpStatus.OK.value())));
+    }
+
+    @AfterEach
+    public void stopWireMockServer() {
+        wireMockServer.stop();
+    }
+
+    @Test
+    void givenRestCalls_whenBothReturnsOk_thenReturnCorrectResult() throws ExecutionException, InterruptedException {
+        stubFor(get(urlEqualTo("/payment_methods?site_id=BR")).willReturn(aResponse().withStatus(HttpStatus.OK.value())
+            .withBody("credit_card")));
+
+        String result = purchaseService.executePurchase("BR");
+
+        assertNotNull(result);
+        assertEquals("Purchase executed with payment method credit_card", result);
+    }
+
+    @Test
+    void givenRestCalls_whenPurchaseReturns404_thenReturnDefault() throws ExecutionException, InterruptedException {
+        stubFor(get(urlEqualTo("/payment_methods?site_id=BR")).willReturn(aResponse().withStatus(HttpStatus.NOT_FOUND.value())));
+
+        String result = purchaseService.executePurchase("BR");
+
+        assertNotNull(result);
+        assertEquals("Purchase executed with payment method cash", result);
+    }
+
+    @Test
+    @Disabled
+    void givenRestCalls_whenPurchaseCompletableFutureTimeout_thenThrowNewException() {
+        stubFor(get(urlEqualTo("/payment_methods?site_id=BR")).willReturn(aResponse().withFixedDelay(550)));
+
+        Throwable error = assertThrows(ExecutionException.class, () -> purchaseService.executePurchase("BR"));
+
+        assertEquals("java.lang.RuntimeException: Thread timeout!", error.getMessage());
+    }
+
+    @Test
+    void givenRestCalls_whenPurchaseRequestWebTimeout_thenThrowNewException() {
+        stubFor(get(urlEqualTo("/payment_methods?site_id=BR")).willReturn(aResponse().withFixedDelay(250)));
+
+        Throwable error = assertThrows(ExecutionException.class, () -> purchaseService.executePurchase("BR"));
+
+        assertEquals("java.lang.RuntimeException: REST call network timeout!", error.getMessage());
+    }
+}