Merge pull request #7898 from kamleshkr/BAEL-1363

BAEL-1363 Fallback for Zuul Routes

spring-cloud/pom.xml

@@ -25,7 +25,7 @@
         <module>spring-cloud-zookeeper</module>
         <module>spring-cloud-gateway</module>
         <module>spring-cloud-stream</module>
-		<module>spring-cloud-stream-starters/twitterhdfs</module>
+        <module>spring-cloud-stream-starters/twitterhdfs</module>
         <module>spring-cloud-connectors-heroku</module>
         <module>spring-cloud-aws</module>
         <module>spring-cloud-consul</module>
@@ -35,9 +35,10 @@
         <module>spring-cloud-archaius</module>
         <module>spring-cloud-functions</module>        
         <module>spring-cloud-vault</module>
-		<!-- <module>spring-cloud-security</module> --> <!-- Fixing in BAEL-10887 -->
-		<module>spring-cloud-task</module>
+        <!-- <module>spring-cloud-security</module> --> <!-- Fixing in BAEL-10887 -->
+        <module>spring-cloud-task</module>
         <module>spring-cloud-zuul</module>
+        <module>spring-cloud-zuul-fallback</module>
     </modules>
 
     <build>

spring-cloud/spring-cloud-zuul-fallback/README.md

@@ -0,0 +1,2 @@
+### Relevant Articles:
+- [Fallback for Zuul Route](TODO)

spring-cloud/spring-cloud-zuul-fallback/api-gateway/pom.xml

@@ -0,0 +1,43 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>api-gateway</artifactId>
+    <name>api-gateway</name>
+    <description>API Gateway using Zuul</description>
+    <packaging>jar</packaging>
+
+    <parent>
+        <groupId>com.baeldung.spring.cloud</groupId>
+        <artifactId>spring-cloud-zuul-fallback</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.cloud</groupId>
+                <artifactId>spring-cloud-starter-parent</artifactId>
+                <version>${spring-cloud-dependencies.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+</project>

spring-cloud/spring-cloud-zuul-fallback/api-gateway/src/main/java/com/baeldung/spring/cloud/apigateway/ApiGatewayApplication.java

@@ -0,0 +1,15 @@
+package com.baeldung.spring.cloud.apigateway;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
+
+@SpringBootApplication
+@EnableZuulProxy
+public class ApiGatewayApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(ApiGatewayApplication.class, args);
+    }
+
+}

spring-cloud/spring-cloud-zuul-fallback/api-gateway/src/main/java/com/baeldung/spring/cloud/apigateway/fallback/GatewayClientResponse.java

@@ -0,0 +1,69 @@
+package com.baeldung.spring.cloud.apigateway.fallback;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.MediaType;
+import org.springframework.http.client.ClientHttpResponse;
+
+public class GatewayClientResponse implements ClientHttpResponse {
+
+    private HttpStatus status;
+    private String message;
+
+    public GatewayClientResponse(HttpStatus status, String message) {
+        this.status = status;
+        this.message = message;
+    }
+
+    @Override
+    public HttpStatus getStatusCode() throws IOException {
+        return status;
+    }
+
+    @Override
+    public int getRawStatusCode() throws IOException {
+        return status.value();
+    }
+
+    @Override
+    public String getStatusText() throws IOException {
+        return status.getReasonPhrase();
+    }
+
+    @Override
+    public void close() {
+    }
+
+    @Override
+    public InputStream getBody() throws IOException {
+        return new ByteArrayInputStream(message.getBytes());
+    }
+
+    @Override
+    public HttpHeaders getHeaders() {
+        HttpHeaders headers = new HttpHeaders();
+        headers.setContentType(MediaType.APPLICATION_JSON);
+        return headers;
+    }
+
+    public HttpStatus getStatus() {
+        return status;
+    }
+
+    public void setStatus(HttpStatus status) {
+        this.status = status;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+
+}

spring-cloud/spring-cloud-zuul-fallback/api-gateway/src/main/java/com/baeldung/spring/cloud/apigateway/fallback/GatewayServiceFallback.java

@@ -0,0 +1,29 @@
+package com.baeldung.spring.cloud.apigateway.fallback;
+
+import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.stereotype.Component;
+
+import com.netflix.hystrix.exception.HystrixTimeoutException;
+
+@Component
+class GatewayServiceFallback implements FallbackProvider {
+
+    private static final String DEFAULT_MESSAGE = "Service not available.";
+
+    @Override
+    public String getRoute() {
+        return "*"; // or return null;
+    }
+
+    @Override
+    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
+        if (cause instanceof HystrixTimeoutException) {
+            return new GatewayClientResponse(HttpStatus.GATEWAY_TIMEOUT, DEFAULT_MESSAGE);
+        } else {
+            return new GatewayClientResponse(HttpStatus.INTERNAL_SERVER_ERROR, DEFAULT_MESSAGE);
+        }
+    }
+
+}

spring-cloud/spring-cloud-zuul-fallback/api-gateway/src/main/java/com/baeldung/spring/cloud/apigateway/fallback/WeatherServiceFallback.java

@@ -0,0 +1,29 @@
+package com.baeldung.spring.cloud.apigateway.fallback;
+
+import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.stereotype.Component;
+
+import com.netflix.hystrix.exception.HystrixTimeoutException;
+
+@Component
+class WeatherServiceFallback implements FallbackProvider {
+
+    private static final String DEFAULT_MESSAGE = "Weather information is not available.";
+
+    @Override
+    public String getRoute() {
+        return "weather-service";
+    }
+
+    @Override
+    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
+        if (cause instanceof HystrixTimeoutException) {
+            return new GatewayClientResponse(HttpStatus.GATEWAY_TIMEOUT, DEFAULT_MESSAGE);
+        } else {
+            return new GatewayClientResponse(HttpStatus.INTERNAL_SERVER_ERROR, DEFAULT_MESSAGE);
+        }
+    }
+
+}

spring-cloud/spring-cloud-zuul-fallback/api-gateway/src/main/resources/application.yml

@@ -0,0 +1,22 @@
+spring:
+   application:
+      name: api-gateway
+server:
+   port: 7070
+  
+zuul:
+   igoredServices: '*'
+   routes:
+      weather-service:
+         path: /weather/**
+         serviceId: weather-service
+         strip-prefix: false
+
+ribbon:
+   eureka:
+      enabled: false
+
+weather-service:
+   ribbon:
+      listOfServers: localhost:8080
+

spring-cloud/spring-cloud-zuul-fallback/api-gateway/src/test/java/com/baeldung/spring/cloud/apigateway/ApiGatewayApplicationIntegrationTest.java

@@ -0,0 +1,16 @@
+package com.baeldung.spring.cloud.apigateway;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class ApiGatewayApplicationIntegrationTest {
+
+    @Test
+    public void whenSpringContextIsBootstrapped_thenNoExceptions() {
+    }
+
+}

spring-cloud/spring-cloud-zuul-fallback/api-gateway/src/test/java/com/baeldung/spring/cloud/apigateway/fallback/GatewayServiceFallbackUnitTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.spring.cloud.apigateway.fallback;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import com.netflix.hystrix.exception.HystrixTimeoutException;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class GatewayServiceFallbackUnitTest {
+
+    private static final String ROUTE = "*";
+
+    @Autowired
+    private GatewayServiceFallback fallback;
+
+    @Test
+    public void testWhenGetRouteThenReturnWeatherServiceRoute() {
+        assertEquals(ROUTE, fallback.getRoute());
+
+    }
+
+    @Test
+    public void testFallbackResponse_whenHystrixException_thenGatewayTimeout() throws Exception {
+        HystrixTimeoutException exception = new HystrixTimeoutException();
+        ClientHttpResponse response = fallback.fallbackResponse(ROUTE, exception);
+
+        assertEquals(HttpStatus.GATEWAY_TIMEOUT, response.getStatusCode());
+    }
+
+    @Test
+    public void testFallbackResponse_whenNonHystrixException_thenInternalServerError() throws Exception {
+        RuntimeException exception = new RuntimeException("Test exception");
+        ClientHttpResponse response = fallback.fallbackResponse(ROUTE, exception);
+
+        assertEquals(HttpStatus.INTERNAL_SERVER_ERROR, response.getStatusCode());
+    }
+
+}

spring-cloud/spring-cloud-zuul-fallback/api-gateway/src/test/java/com/baeldung/spring/cloud/apigateway/fallback/WeatherServiceFallbackUnitTest.java

@@ -0,0 +1,46 @@
+package com.baeldung.spring.cloud.apigateway.fallback;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import com.netflix.hystrix.exception.HystrixTimeoutException;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class WeatherServiceFallbackUnitTest {
+
+    private static final String ROUTE = "weather-service";
+
+    @Autowired
+    private WeatherServiceFallback fallback;
+
+    @Test
+    public void testWhenGetRouteThenReturnWeatherServiceRoute() {
+        assertEquals(ROUTE, fallback.getRoute());
+
+    }
+
+    @Test
+    public void testFallbackResponse_whenHystrixException_thenGatewayTimeout() throws Exception {
+        HystrixTimeoutException exception = new HystrixTimeoutException();
+        ClientHttpResponse response = fallback.fallbackResponse(ROUTE, exception);
+
+        assertEquals(HttpStatus.GATEWAY_TIMEOUT, response.getStatusCode());
+    }
+
+    @Test
+    public void testFallbackResponse_whenNonHystrixException_thenInternalServerError() throws Exception {
+        RuntimeException exception = new RuntimeException("Test exception");
+        ClientHttpResponse response = fallback.fallbackResponse(ROUTE, exception);
+
+        assertEquals(HttpStatus.INTERNAL_SERVER_ERROR, response.getStatusCode());
+    }
+
+}

spring-cloud/spring-cloud-zuul-fallback/pom.xml

@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>spring-cloud-zuul-fallback</artifactId>
+    <packaging>pom</packaging>
+    <name>spring-cloud-zuul-fallback</name>
+    <description>Spring Cloud Zuul Fallback</description>
+
+    <parent>
+        <groupId>com.baeldung.spring.cloud</groupId>
+        <artifactId>spring-cloud</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+        <relativePath>..</relativePath>
+    </parent>
+
+    <modules>
+        <module>api-gateway</module>
+        <module>weather-service</module>
+    </modules>
+
+    <properties>
+        <java.version>1.8</java.version>
+        <spring-cloud-dependencies.version>Finchley.SR2</spring-cloud-dependencies.version>
+        <maven-jar-plugin.version>3.1.1</maven-jar-plugin.version>
+    </properties>
+</project>

spring-cloud/spring-cloud-zuul-fallback/weather-service/pom.xml

@@ -0,0 +1,39 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <artifactId>weather-service</artifactId>
+    <name>Weather Service</name>
+    <description>Weather Service for Zuul Fallback Test</description>
+
+    <parent>
+        <groupId>com.baeldung.spring.cloud</groupId>
+        <artifactId>spring-cloud-zuul-fallback</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <dependencyManagement>
+        <dependencies>
+            <dependency>
+                <groupId>org.springframework.cloud</groupId>
+                <artifactId>spring-cloud-starter-parent</artifactId>
+                <version>${spring-cloud-dependencies.version}</version>
+                <type>pom</type>
+                <scope>import</scope>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+</project>

spring-cloud/spring-cloud-zuul-fallback/weather-service/src/main/java/com/baeldung/spring/cloud/weatherservice/WeatherController.java

@@ -0,0 +1,16 @@
+package com.baeldung.spring.cloud.weatherservice;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/weather")
+public class WeatherController {
+
+    @GetMapping("/today")
+    public String getMessage() {
+        return "It's a bright sunny day today!";
+    }
+
+}

spring-cloud/spring-cloud-zuul-fallback/weather-service/src/main/java/com/baeldung/spring/cloud/weatherservice/WeatherServiceApplication.java

@@ -0,0 +1,13 @@
+package com.baeldung.spring.cloud.weatherservice;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class WeatherServiceApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(WeatherServiceApplication.class, args);
+    }
+
+}

spring-cloud/spring-cloud-zuul-fallback/weather-service/src/main/resources/application.yml

@@ -0,0 +1,4 @@
+spring:
+   application:
+      name: weather-service
+

spring-cloud/spring-cloud-zuul-fallback/weather-service/src/test/java/com/baeldung/spring/cloud/weatherservice/WeatherControllerIntegrationTest.java

@@ -0,0 +1,31 @@
+package com.baeldung.spring.cloud.weatherservice;
+
+import static org.hamcrest.Matchers.containsString;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.get;
+import static org.springframework.test.web.servlet.result.MockMvcResultHandlers.print;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.content;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.status;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.servlet.MockMvc;
+
+@RunWith(SpringRunner.class)
+@WebMvcTest(WeatherController.class)
+public class WeatherControllerIntegrationTest {
+
+    @Autowired
+    private MockMvc mockMvc;
+
+    @Test
+    public void whenWeatherControllerInvoked_thenReturnWeatherInformation() throws Exception {
+        this.mockMvc.perform(get("/weather/today"))
+            .andDo(print())
+            .andExpect(status().isOk())
+            .andExpect(content().string(containsString("bright sunny day")));
+    }
+
+}

spring-cloud/spring-cloud-zuul-fallback/weather-service/src/test/java/com/baeldung/spring/cloud/weatherservice/WeatherServiceApplicationIntegrationTest.java

@@ -0,0 +1,16 @@
+package com.baeldung.spring.cloud.weatherservice;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest
+public class WeatherServiceApplicationIntegrationTest {
+
+    @Test
+    public void whenSpringContextIsBootstrapped_thenNoExceptions() {
+    }
+
+}