feat: Distributed tracing (#3006)

* added microservices distributed tracing pattern * feat: Implement Microservice pattern: Distributed tracing #2693
2026-08-21 08:26:16 +00:00 · 2024-07-20 13:42:12 +03:00
parent 1d454f7721
commit 9c43d85f36
35 changed files with 1724 additions and 0 deletions
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+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.order.microservice;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * With the Microservices pattern, a request often travels through multiple different microservices.
+ * Tracking the entire request flow across these services can be challenging, especially when trying
+ * to diagnose performance issues or failures. Distributed tracing addresses this challenge by
+ * providing end-to-end visibility into the lifecycle of a request as it passes through various
+ * microservices.
+ *
+ * <p>The intent of the Distributed Tracing pattern is to trace a request across different
+ * microservices, collecting detailed timing data and logs that help in understanding the flow,
+ * performance bottlenecks, and failure points in a distributed system. Each microservice involved
+ * in the request contributes to the tracing data, creating a comprehensive view of the request's
+ * journey.
+ *
+ * <p>This implementation demonstrates distributed tracing in a microservices architecture for an
+ * e-commerce platform. When a customer places an order, the {@link OrderService} interacts with
+ * both the payment-microservice to process the payment and the product-microservice to check the
+ * product inventory. Tracing logs are generated for each interaction, and these logs can be
+ * visualized using Zipkin.
+ *
+ * <p>To run Zipkin and view the tracing logs, you can use the following Docker command:
+ *
+ * <pre>
+ * {@code docker run -d -p 9411:9411 --name zipkin openzipkin/zipkin }
+ * </pre>
+ *
+ * <p>Start Zipkin with the command above. Once Zipkin is running, you can
+ * access the Zipkin UI at `<a href="http://localhost:9411">...</a>`
+ * to view the tracing logs and analyze the request flows across your microservices.
+ *
+ *
+ * <p>To place an order and generate tracing data, you can use the following curl command:
+ *
+ * <pre>
+ * {@code curl -X POST http://localhost:30300/order -H "Content-Type: application/json" -d '{"orderId": "123"}' }
+ * </pre>
+ *
+ * <p>This command sends a POST request to create an order, which will trigger interactions with the
+ * payment and product microservices, generating tracing logs that can be viewed in Zipkin.
+ *
+ */
+@SpringBootApplication
+public class Main {
+  /**
+   * Program entry point.
+   *
+   * @param args command line args
+   */
+  public static void main(String[] args) {
+    SpringApplication.run(Main.class, args);
+  }
+}
@@ -0,0 +1,64 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.order.microservice;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * This controller handles order processing by calling necessary microservices.
+ */
+@Slf4j
+@RestController
+public class OrderController {
+
+  private final OrderService orderService;
+
+  /**
+   * Constructor to inject OrderService.
+   *
+   * @param orderService the service to process orders
+   */
+  public OrderController(final OrderService orderService) {
+    this.orderService = orderService;
+  }
+
+  /**
+   * Endpoint to process an order.
+   *
+   * @param request the order request body (can be null)
+   * @return ResponseEntity with a status message
+   */
+  @PostMapping("/order")
+  public ResponseEntity<String> processOrder(@RequestBody(required = false) String request) {
+    LOGGER.info("Received order request: {}", request);
+    var result = orderService.processOrder();
+    LOGGER.info("Order processed result: {}", result);
+    return ResponseEntity.ok(result);
+  }
+}
@@ -0,0 +1,103 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.order.microservice;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.boot.web.client.RestTemplateBuilder;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Service;
+import org.springframework.web.client.HttpClientErrorException;
+import org.springframework.web.client.ResourceAccessException;
+
+/**
+ * Service to handle order processing logic.
+ */
+@Slf4j
+@Service
+public class OrderService {
+
+  private final RestTemplateBuilder restTemplateBuilder;
+
+  /**
+   * Constructor to inject RestTemplateBuilder.
+   *
+   * @param restTemplateBuilder the RestTemplateBuilder to build RestTemplate instances
+   */
+  public OrderService(final RestTemplateBuilder restTemplateBuilder) {
+    this.restTemplateBuilder = restTemplateBuilder;
+  }
+
+  /**
+   * Processes an order by calling
+   * {@link OrderService#validateProduct()} and
+   * {@link OrderService#processPayment()}.
+   *
+   * @return A string indicating whether the order was processed successfully or failed.
+   */
+  public String processOrder() {
+    if (validateProduct() && processPayment()) {
+      return "Order processed successfully";
+    }
+    return "Order processing failed";
+  }
+
+  /**
+   * Validates the product by calling the respective microservice.
+   *
+   * @return true if the product is valid, false otherwise.
+   */
+  Boolean validateProduct() {
+    try {
+      ResponseEntity<Boolean> productValidationResult = restTemplateBuilder
+          .build()
+          .postForEntity("http://localhost:30302/product/validate", "validating product",
+              Boolean.class);
+      LOGGER.info("Product validation result: {}", productValidationResult.getBody());
+      return productValidationResult.getBody();
+    } catch (ResourceAccessException | HttpClientErrorException e) {
+      LOGGER.error("Error communicating with product service: {}", e.getMessage());
+      return false;
+    }
+  }
+
+  /**
+   * Validates the product by calling the respective microservice.
+   *
+   * @return true if the product is valid, false otherwise.
+   */
+  Boolean processPayment() {
+    try {
+      ResponseEntity<Boolean> paymentProcessResult = restTemplateBuilder
+          .build()
+          .postForEntity("http://localhost:30301/payment/process", "processing payment",
+              Boolean.class);
+      LOGGER.info("Payment processing result: {}", paymentProcessResult.getBody());
+      return paymentProcessResult.getBody();
+    } catch (ResourceAccessException | HttpClientErrorException e) {
+      LOGGER.error("Error communicating with payment service: {}", e.getMessage());
+      return false;
+    }
+  }
+}
@@ -0,0 +1,33 @@
+#
+# The MIT License
+# Copyright © 2014-2021 Ilkka Seppälä
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+
+spring.application.name=order-microservice
+server.port=30300
+
+management.tracing.sampling.probability=1
+logging.pattern.level=%5p [${spring.zipkin.service.name:${spring.application.name:}},%X{traceId:-},%X{spanId:-}]
+management.tracing.propagation.type=w3c
+management.tracing.baggage.enabled=true
+management.tracing.enabled=true
+management.zipkin.tracing.endpoint=http://localhost:9411/api/v2/spans
+
@@ -0,0 +1,39 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.order.microservice;
+
+import static org.junit.jupiter.api.Assertions.assertDoesNotThrow;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Application test
+ */
+class MainTest {
+  @Test
+  void shouldExecuteApplicationWithoutException() {
+    assertDoesNotThrow(() -> Main.main(new String[]{}));
+  }
+}
@@ -0,0 +1,76 @@
+package com.iluwatar.order.microservice;/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.springframework.http.ResponseEntity;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.Mockito.when;
+
+/**
+ * OrderControllerTest class to test the OrderController.
+ */
+class OrderControllerTest {
+
+  @InjectMocks
+  private OrderController orderController;
+
+  @Mock
+  private OrderService orderService;
+
+  @BeforeEach
+  void setup() {
+    MockitoAnnotations.openMocks(this);
+  }
+
+  /**
+   * Test to process the order successfully.
+   */
+  @Test
+  void processOrderShouldReturnSuccessStatus() {
+    // Arrange
+    when(orderService.processOrder()).thenReturn("Order processed successfully");
+    // Act
+    ResponseEntity<String> response = orderController.processOrder("test order");
+    // Assert
+    assertEquals("Order processed successfully", response.getBody());
+  }
+
+  /**
+   * Test to process the order with failure.
+   */
+  @Test
+  void ProcessOrderShouldReturnFailureStatusWhen() {
+    // Arrange
+    when(orderService.processOrder()).thenReturn("Order processing failed");
+    // Act
+    ResponseEntity<String> response = orderController.processOrder("test order");
+    // Assert
+    assertEquals("Order processing failed", response.getBody());
+  }
+}
@@ -0,0 +1,192 @@
+/*
+ * This project is licensed under the MIT license. Module model-view-viewmodel is using ZK framework licensed under LGPL (see lgpl-3.0.txt).
+ *
+ * The MIT License
+ * Copyright © 2014-2022 Ilkka Seppälä
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+package com.iluwatar.order.microservice;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.when;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.springframework.boot.web.client.RestTemplateBuilder;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.client.RestTemplate;
+import org.springframework.web.client.HttpClientErrorException;
+import org.springframework.web.client.ResourceAccessException;
+
+/**
+ * OrderServiceTest class to test the OrderService.
+ */
+class OrderServiceTest {
+
+  @InjectMocks
+  private OrderService orderService;
+
+  @Mock
+  private RestTemplateBuilder restTemplateBuilder;
+
+  @Mock
+  private RestTemplate restTemplate;
+
+  @BeforeEach
+  void setup() {
+    MockitoAnnotations.openMocks(this);
+    when(restTemplateBuilder.build()).thenReturn(restTemplate);
+  }
+
+  /**
+   * Test to process the order successfully.
+   */
+  @Test
+  void testProcessOrder_Success() {
+    // Arrange
+    when(restTemplate.postForEntity(eq("http://localhost:30302/product/validate"), anyString(), eq(Boolean.class)))
+        .thenReturn(ResponseEntity.ok(true));
+    when(restTemplate.postForEntity(eq("http://localhost:30301/payment/process"), anyString(), eq(Boolean.class)))
+        .thenReturn(ResponseEntity.ok(true));
+    // Act
+    String result = orderService.processOrder();
+    // Assert
+    assertEquals("Order processed successfully", result);
+  }
+
+  /**
+   * Test to process the order with failure caused by product validation failure.
+   */
+  @Test
+  void testProcessOrder_FailureWithProductValidationFailure() {
+    // Arrange
+    when(restTemplate.postForEntity(eq("http://localhost:30302/product/validate"), anyString(), eq(Boolean.class)))
+        .thenReturn(ResponseEntity.ok(false));
+    // Act
+    String result = orderService.processOrder();
+    // Assert
+    assertEquals("Order processing failed", result);
+  }
+
+  /**
+   * Test to process the order with failure caused by payment processing failure.
+   */
+  @Test
+  void testProcessOrder_FailureWithPaymentProcessingFailure() {
+    // Arrange
+    when(restTemplate.postForEntity(eq("http://localhost:30302/product/validate"), anyString(), eq(Boolean.class)))
+        .thenReturn(ResponseEntity.ok(true));
+    when(restTemplate.postForEntity(eq("http://localhost:30301/payment/process"), anyString(), eq(Boolean.class)))
+        .thenReturn(ResponseEntity.ok(false));
+    // Act
+    String result = orderService.processOrder();
+    // Assert
+    assertEquals("Order processing failed", result);
+  }
+
+  /**
+   * Test to validate the product.
+   */
+  @Test
+  void testValidateProduct() {
+    // Arrange
+    when(restTemplate.postForEntity(eq("http://localhost:30302/product/validate"), anyString(), eq(Boolean.class)))
+        .thenReturn(ResponseEntity.ok(true));
+    // Act
+    Boolean result = orderService.validateProduct();
+    // Assert
+    assertEquals(true, result);
+  }
+
+  /**
+   * Test to process the payment.
+   */
+  @Test
+  void testProcessPayment() {
+    // Arrange
+    when(restTemplate.postForEntity(eq("http://localhost:30301/payment/process"), anyString(), eq(Boolean.class)))
+        .thenReturn(ResponseEntity.ok(true));
+    // Act
+    Boolean result = orderService.processPayment();
+    // Assert
+    assertEquals(true, result);
+  }
+
+  /**
+   * Test to validate the product with ResourceAccessException.
+   */
+  @Test
+  void testValidateProduct_ResourceAccessException() {
+    // Arrange
+    when(restTemplate.postForEntity(eq("http://localhost:30302/product/validate"), anyString(), eq(Boolean.class)))
+        .thenThrow(new ResourceAccessException("Service unavailable"));
+    // Act
+    Boolean result = orderService.validateProduct();
+    // Assert
+    assertEquals(false, result);
+  }
+
+  /**
+   * Test to validate the product with HttpClientErrorException.
+   */
+  @Test
+  void testValidateProduct_HttpClientErrorException() {
+    // Arrange
+    when(restTemplate.postForEntity(eq("http://localhost:30302/product/validate"), anyString(), eq(Boolean.class)))
+        .thenThrow(new HttpClientErrorException(org.springframework.http.HttpStatus.BAD_REQUEST, "Bad request"));
+    // Act
+    Boolean result = orderService.validateProduct();
+    // Assert
+    assertEquals(false, result);
+  }
+
+  /**
+   * Test to process the payment with ResourceAccessException.
+   */
+  @Test
+  void testProcessPayment_ResourceAccessException() {
+    // Arrange
+    when(restTemplate.postForEntity(eq("http://localhost:30301/payment/process"), anyString(), eq(Boolean.class)))
+        .thenThrow(new ResourceAccessException("Service unavailable"));
+    // Act
+    Boolean result = orderService.processPayment();
+    // Assert
+    assertEquals(false, result);
+  }
+
+  /**
+   * Test to process the payment with HttpClientErrorException.
+   */
+  @Test
+  void testProcessPayment_HttpClientErrorException() {
+    // Arrange
+    when(restTemplate.postForEntity(eq("http://localhost:30301/payment/process"), anyString(), eq(Boolean.class)))
+        .thenThrow(new HttpClientErrorException(org.springframework.http.HttpStatus.BAD_REQUEST, "Bad request"));
+    // Act
+    Boolean result = orderService.processPayment();
+    // Assert
+    assertEquals(false, result);
+  }
+}