Validate Create Order Request

 Implemented OrderValidator to call catalog-service and check product code and price are valid
 Used resilience4j to apply circuit breaker and retry
 Used timeout configuration with RestClient
 Used WireMock for mocking catalog-service integration for testing

Author: kavindu-pere

order-service/pom.xml

@@ -15,10 +15,10 @@
     <description>Order Service</description>
     <properties>
         <java.version>21</java.version>
-        <spring-cloud.version>2023.0.1</spring-cloud.version>
         <springdoc-openapi.version>2.5.0</springdoc-openapi.version>
         <instancio.version>4.5.1</instancio.version>
         <spotless.version>2.43.0</spotless.version>
+        <resilience4j-spring-boot3.version>2.2.0</resilience4j-spring-boot3.version>
         <dockerImageName>kavinduperera/bookstore-${project.artifactId}</dockerImageName>
     </properties>
     <dependencies>
@@ -46,9 +46,11 @@
             <groupId>org.flywaydb</groupId>
             <artifactId>flyway-core</artifactId>
         </dependency>
+
         <dependency>
-            <groupId>org.springframework.cloud</groupId>
-            <artifactId>spring-cloud-starter-circuitbreaker-resilience4j</artifactId>
+            <groupId>io.github.resilience4j</groupId>
+            <artifactId>resilience4j-spring-boot3</artifactId>
+            <version>${resilience4j-spring-boot3.version}</version>
         </dependency>
         <dependency>
             <groupId>org.springdoc</groupId>
@@ -118,18 +120,19 @@
             <version>${instancio.version}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.wiremock</groupId>
+            <artifactId>wiremock-standalone</artifactId>
+            <version>3.5.2</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.wiremock.integrations.testcontainers</groupId>
+            <artifactId>wiremock-testcontainers-module</artifactId>
+            <version>1.0-alpha-13</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
-    <dependencyManagement>
-        <dependencies>
-            <dependency>
-                <groupId>org.springframework.cloud</groupId>
-                <artifactId>spring-cloud-dependencies</artifactId>
-                <version>${spring-cloud.version}</version>
-                <type>pom</type>
-                <scope>import</scope>
-            </dependency>
-        </dependencies>
-    </dependencyManagement>
 
     <build>
         <plugins>

order-service/src/main/java/com/codebykavindu/bookstore/orders/ApplicationProperties.java

@@ -7,6 +7,7 @@
  */
 @ConfigurationProperties(prefix = "orders")
 public record ApplicationProperties(
+        String catalogServiceUrl,
         String orderEventsExchange,
         String newOrdersQueue,
         String deliveredOrdersQueue,

order-service/src/main/java/com/codebykavindu/bookstore/orders/clients/catalog/CatalogServiceClientConfig.java

@@ -0,0 +1,26 @@
+package com.codebykavindu.bookstore.orders.clients.catalog;
+
+import com.codebykavindu.bookstore.orders.ApplicationProperties;
+import java.time.Duration;
+import org.springframework.boot.web.client.ClientHttpRequestFactories;
+import org.springframework.boot.web.client.ClientHttpRequestFactorySettings;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.client.RestClient;
+
+/**
+ * @author Kavindu Perera
+ */
+@Configuration
+class CatalogServiceClientConfig {
+
+    @Bean
+    RestClient restClient(ApplicationProperties properties) {
+        return RestClient.builder()
+                .baseUrl(properties.catalogServiceUrl())
+                .requestFactory(ClientHttpRequestFactories.get(ClientHttpRequestFactorySettings.DEFAULTS
+                        .withConnectTimeout(Duration.ofSeconds(5))
+                        .withReadTimeout(Duration.ofSeconds(5))))
+                .build();
+    }
+}

order-service/src/main/java/com/codebykavindu/bookstore/orders/clients/catalog/Product.java

@@ -0,0 +1,8 @@
+package com.codebykavindu.bookstore.orders.clients.catalog;
+
+import java.math.BigDecimal;
+
+/**
+ * @author Kavindu Perera
+ */
+public record Product(String code, String name, String description, String imageUrl, BigDecimal price) {}

order-service/src/main/java/com/codebykavindu/bookstore/orders/clients/catalog/ProductServiceClient.java

@@ -0,0 +1,37 @@
+package com.codebykavindu.bookstore.orders.clients.catalog;
+
+import io.github.resilience4j.circuitbreaker.annotation.CircuitBreaker;
+import io.github.resilience4j.retry.annotation.Retry;
+import java.util.Optional;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+import org.springframework.web.client.RestClient;
+
+/**
+ * @author Kavindu Perera
+ */
+@Component
+public class ProductServiceClient {
+    private static final Logger log = LoggerFactory.getLogger(ProductServiceClient.class);
+
+    private final RestClient restClient;
+
+    ProductServiceClient(RestClient restClient) {
+        this.restClient = restClient;
+    }
+
+    @CircuitBreaker(name = "catalog-service")
+    @Retry(name = "catalog-service", fallbackMethod = "getProductByCodeFallback")
+    public Optional<Product> getProductByCode(String code) {
+        log.info("Fetching product with code: {}", code);
+        var product =
+                restClient.get().uri("api/v1/products/{code}", code).retrieve().body(Product.class);
+        return Optional.ofNullable(product);
+    }
+
+    Optional<Product> getProductByCodeFallback(String code, Throwable t) {
+        log.error("ProductServiceClient.getProductByCodeFallback: code {}", code);
+        return Optional.empty();
+    }
+}

order-service/src/main/java/com/codebykavindu/bookstore/orders/domain/OrderService.java

@@ -16,12 +16,15 @@ public class OrderService {
     private static final Logger log = LoggerFactory.getLogger(OrderService.class);
 
     private final OrderRepository orderRepository;
+    private final OrderValidator orderValidator;
 
-    OrderService(OrderRepository orderRepository) {
+    OrderService(OrderRepository orderRepository, OrderValidator orderValidator) {
         this.orderRepository = orderRepository;
+        this.orderValidator = orderValidator;
     }
 
     public CreateOrderResponse createOrder(String userName, CreateOrderRequest request) {
+        orderValidator.validate(request);
         OrderEntity newOrder = OrderMapper.convertToEntity(request);
         newOrder.setUserName(userName);
         OrderEntity savedOrder = this.orderRepository.save(newOrder);

order-service/src/main/java/com/codebykavindu/bookstore/orders/domain/OrderValidator.java

@@ -0,0 +1,39 @@
+package com.codebykavindu.bookstore.orders.domain;
+
+import com.codebykavindu.bookstore.orders.clients.catalog.Product;
+import com.codebykavindu.bookstore.orders.clients.catalog.ProductServiceClient;
+import com.codebykavindu.bookstore.orders.domain.models.CreateOrderRequest;
+import com.codebykavindu.bookstore.orders.domain.models.OrderItem;
+import java.util.Set;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.stereotype.Component;
+
+/**
+ * @author Kavindu Perera
+ */
+@Component
+class OrderValidator {
+    private static final Logger log = LoggerFactory.getLogger(OrderValidator.class);
+
+    private final ProductServiceClient client;
+
+    OrderValidator(ProductServiceClient client) {
+        this.client = client;
+    }
+
+    void validate(CreateOrderRequest request) {
+        Set<OrderItem> items = request.items();
+        for (OrderItem item : items) {
+            Product product = client.getProductByCode(item.code())
+                    .orElseThrow(() -> new InvalidOrderException("Invalid Product code: " + item.code()));
+            if (item.price().compareTo(product.price()) != 0) {
+                log.error(
+                        "Product price not matching for. Actual price:{}, received price:{}",
+                        product.price(),
+                        item.price());
+                throw new InvalidOrderException("Product price not matching");
+            }
+        }
+    }
+}

order-service/src/main/java/com/codebykavindu/bookstore/orders/web/controllers/OrderController.java

@@ -25,7 +25,7 @@ class OrderController {
     private final OrderService orderService;
     private final SecurityService securityService;
 
-    public OrderController(OrderService orderService, SecurityService securityService) {
+    OrderController(OrderService orderService, SecurityService securityService) {
         this.orderService = orderService;
         this.securityService = securityService;
     }

order-service/src/main/java/com/codebykavindu/bookstore/orders/web/controllers/RabbitMQController.java

@@ -14,7 +14,7 @@ class RabbitMQController {
     private final RabbitTemplate rabbitTemplate;
     private final ApplicationProperties properties;
 
-    public RabbitMQController(RabbitTemplate rabbitTemplate, ApplicationProperties properties) {
+    RabbitMQController(RabbitTemplate rabbitTemplate, ApplicationProperties properties) {
         this.rabbitTemplate = rabbitTemplate;
         this.properties = properties;
     }

order-service/src/main/resources/application.properties

@@ -5,6 +5,7 @@ management.endpoints.web.exposure.include=*
 management.info.git.mode=full
 
 # Order Service Configurations
+orders.catalog-service-url=http://localhost:8081
 orders.order-events-exchange=orders-exchange
 orders.new-orders-queue=new-orders
 orders.delivered-orders-queue=delivered-orders
@@ -21,4 +22,15 @@ spring.jpa.open-in-view=false
 spring.rabbitmq.host=${RABBITMQ_HOST:localhost}
 spring.rabbitmq.port=${RABBITMQ_PORT:5672}
 spring.rabbitmq.username=${RABBITMQ_USERNAME:guest}
-spring.rabbitmq.password=${RABBITMQ_PASSWORD:guest}
+spring.rabbitmq.password=${RABBITMQ_PASSWORD:guest}
+
+# Resilience4j Configurations
+resilience4j.retry.backends.catalog-service.max-attempts=2
+resilience4j.retry.backends.catalog-service.wait-duration=1s
+
+resilience4j.circuitbreaker.backends.catalog-service.sliding-window-type=COUNT_BASED
+resilience4j.circuitbreaker.backends.catalog-service.sliding-window-size=6
+resilience4j.circuitbreaker.backends.catalog-service.minimum-number-of-calls=4
+resilience4j.circuitbreaker.backends.catalog-service.wait-duration-in-open-state=20s
+resilience4j.circuitbreaker.backends.catalog-service.permitted-number-of-calls-in-half-open-state=2
+resilience4j.circuitbreaker.backends.catalog-service.failure-rate-threshold=50

order-service/src/test/java/com/codebykavindu/bookstore/orders/AbstractIntegrationTest.java

@@ -1,12 +1,23 @@
 package com.codebykavindu.bookstore.orders;
 
+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.stubFor;
+import static com.github.tomakehurst.wiremock.client.WireMock.urlMatching;
 import static org.springframework.boot.test.context.SpringBootTest.WebEnvironment.RANDOM_PORT;
 
+import com.github.tomakehurst.wiremock.client.WireMock;
 import io.restassured.RestAssured;
+import java.math.BigDecimal;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.BeforeEach;
 import org.springframework.boot.test.context.SpringBootTest;
 import org.springframework.boot.test.web.server.LocalServerPort;
 import org.springframework.context.annotation.Import;
+import org.springframework.http.MediaType;
+import org.springframework.test.context.DynamicPropertyRegistry;
+import org.springframework.test.context.DynamicPropertySource;
+import org.wiremock.integrations.testcontainers.WireMockContainer;
 
 /**
  * @author Kavindu Perera
@@ -17,8 +28,37 @@ public abstract class AbstractIntegrationTest {
     @LocalServerPort
     int port;
 
+    static WireMockContainer wiremockServer = new WireMockContainer("wiremock/wiremock:3.5.2-alpine");
+
+    @BeforeAll
+    static void beforeAll() {
+        wiremockServer.start();
+        configureFor(wiremockServer.getHost(), wiremockServer.getPort());
+    }
+
+    @DynamicPropertySource
+    static void configureProperties(DynamicPropertyRegistry registry) {
+        registry.add("orders.catalog-service-url", wiremockServer::getBaseUrl);
+    }
+
     @BeforeEach
     void setUp() {
         RestAssured.port = port;
     }
+
+    protected static void mockGetProductByCode(String code, String name, BigDecimal price) {
+        stubFor(WireMock.get(urlMatching("/api/v1/products/" + code))
+                .willReturn(aResponse()
+                        .withHeader("Content-Type", MediaType.APPLICATION_JSON_VALUE)
+                        .withStatus(200)
+                        .withBody(
+                                """
+                    {
+                        "code": "%s",
+                        "name": "%s",
+                        "price": %f
+                    }
+                """
+                                        .formatted(code, name, price.doubleValue()))));
+    }
 }

order-service/src/test/java/com/codebykavindu/bookstore/orders/web/controllers/OrderControllerTests.java

@@ -6,6 +6,7 @@
 import com.codebykavindu.bookstore.orders.AbstractIntegrationTest;
 import com.codebykavindu.bookstore.orders.testdata.TestDataFactory;
 import io.restassured.http.ContentType;
+import java.math.BigDecimal;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.springframework.http.HttpStatus;
@@ -19,33 +20,33 @@ class OrderControllerTests extends AbstractIntegrationTest {
     class CreateOrderTests {
         @Test
         void shouldCreateOrderSuccessfully() {
+            mockGetProductByCode("P100", "Product 1", new BigDecimal("25.50"));
             var payload =
                     """
-                            {
-                                "customer" : {
-                                    "name": "Kavindu",
-                                    "email": "kavindu@gmail.com",
-                                    "phone": "999999999"
-                                },
-                                "deliveryAddress" : {
-                                    "addressLine1": "Birkelweg",
-                                    "addressLine2": "Hans-Edenhofer-Straße 23",
-                                    "city": "Berlin",
-                                    "state": "Berlin",
-                                    "zipCode": "94258",
-                                    "country": "Germany"
-                                },
-                                "items": [
-                                    {
-                                        "code": "P100",
-                                        "name": "Product 1",
-                                        "price": 25.50,
-                                        "quantity": 1
-                                    }
-                                ]
-                            }
+                        {
+                            "customer" : {
+                                "name": "Siva",
+                                "email": "siva@gmail.com",
+                                "phone": "999999999"
+                            },
+                            "deliveryAddress" : {
+                                "addressLine1": "HNO 123",
+                                "addressLine2": "Kukatpally",
+                                "city": "Hyderabad",
+                                "state": "Telangana",
+                                "zipCode": "500072",
+                                "country": "India"
+                            },
+                            "items": [
+                                {
+                                    "code": "P100",
+                                    "name": "Product 1",
+                                    "price": 25.50,
+                                    "quantity": 1
+                                }
+                            ]
+                        }
                     """;
-
             given().contentType(ContentType.JSON)
                     .body(payload)
                     .when()