feat:Step 1 - Add simple consumer calling provider

Author: Phil Endsley

.gitignore

@@ -1,3 +1,36 @@
+consumer/.gradle
+build/
+!../gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+out/
+!**/src/main/**/out/
+!**/src/test/**/out/
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+
+### VS Code ###
+.vscode/
 .gradle
 /build/
 

.idea/.gitignore

@@ -3,3 +3,57 @@
 This workshop is setup with a number of steps that can be run through. Each step is in a branch, so to run through a
 step of the workshop just check out the branch for that step (i.e. `git checkout step1`).
 
+
+## Scenario
+
+There are two components in scope for our workshop.
+
+1. Product Catalog application (Consumer). It provides a console interface to query the Product service for product information.
+1. Product Service (Provider). Provides useful things about products, such as listing all products and getting the details of an individual product.
+
+## Step 1 - Simple Consumer calling Provider
+
+We need to first create an HTTP client to make the calls to our provider service:
+
+![Simple Consumer](diagrams/workshop_step1.svg)
+
+The Consumer has implemented the product service client which has the following:
+
+- `GET /products` - Retrieve all products
+- `GET /products/{id}` - Retrieve a single product by ID
+
+The diagram below highlights the interaction for retrieving a product with ID 10:
+
+![Sequence Diagram](diagrams/workshop_step1_class-sequence-diagram.svg)
+
+You can see the client interface we created in `consumer/src/main/au/com/dius/pactworkshop/consumer/ProductService.java`:
+
+```java
+@Service
+public class ProductService {
+
+    private final RestTemplate restTemplate;
+
+    @Autowired
+    public ProductService(RestTemplate restTemplate) {
+        this.restTemplate = restTemplate;
+    }
+
+    public List<Product> getAllProducts() {
+        return restTemplate.exchange("/products",
+                HttpMethod.GET,
+                null,
+                new ParameterizedTypeReference<List<Product>>(){}).getBody();
+    }
+
+    public Product getProduct(String id) {
+        return restTemplate.getForEntity("/products/{id}", Product.class, id).getBody();
+    }
+}
+```
+
+We can run the client with `./gradlew consumer:bootRun` - it should fail with the error below, because the Provider is not running.
+
+```console
+Caused by: org.springframework.web.client.ResourceAccessException: I/O error on GET request for "http://localhost:8085/products": Connection refused: connect; nested exception is java.net.ConnectException: Connection refused: connect
+```

.idea/misc.xml

@@ -0,0 +1,7 @@
+subprojects {
+    apply plugin: 'java'
+
+    repositories {
+        mavenCentral()
+    }
+}

.idea/vcs.xml

@@ -0,0 +1,22 @@
+plugins {
+	id 'org.springframework.boot' version '2.3.4.RELEASE'
+	id 'io.spring.dependency-management' version '1.0.10.RELEASE'
+}
+
+group = 'au.com.dius.pactworkshop'
+version = '0.0.1-SNAPSHOT'
+sourceCompatibility = '11'
+
+dependencies {
+	implementation 'org.springframework.boot:spring-boot-starter'
+	implementation 'org.springframework.boot:spring-boot-starter-web'
+
+	testImplementation('org.springframework.boot:spring-boot-starter-test') {
+		exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
+	}
+	testImplementation 'com.github.tomakehurst:wiremock:2.27.2'
+}
+
+test {
+	useJUnitPlatform()
+}

README.md

@@ -0,0 +1,65 @@
+package au.com.dius.pactworkshop.consumer;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.CommandLineRunner;
+import org.springframework.stereotype.Component;
+
+import java.util.List;
+import java.util.Scanner;
+import java.util.stream.IntStream;
+
+@Component
+public class ConsoleInterface implements CommandLineRunner {
+
+    private final ProductService productService;
+
+    private List<Product> products;
+
+    @Autowired
+    ConsoleInterface(ProductService productService) {
+        this.productService = productService;
+    }
+
+    @Override
+    public void run(String... args) {
+        Scanner scanner = new Scanner(System.in);
+        while (true) {
+            printAllProducts();
+            Integer choice = getUserChoice(scanner);
+            if (choice == null || choice <= 0 || choice > products.size()) {
+                System.out.println("Exiting...");
+                break;
+            }
+            printProduct(choice);
+        }
+    }
+
+    private void printAllProducts() {
+        products = productService.getAllProducts();
+        System.out.println("\n\nProducts\n--------");
+        IntStream.range(0, products.size())
+                .forEach(index -> System.out.println(String.format("%d) %s", index + 1, products.get(index).getName())));
+    }
+
+    private Integer getUserChoice(Scanner scanner) {
+        System.out.print("Select item to view details: ");
+        String choice = scanner.nextLine();
+        return parseChoice(choice);
+    }
+
+    private void printProduct(int index) {
+        String id = products.get(index - 1).getId();
+        Product product = productService.getProduct(id);
+
+        System.out.println("Product Details\n---------------");
+        System.out.println(product);
+    }
+
+    private Integer parseChoice(String choice) {
+        try {
+            return Integer.parseInt(choice);
+        } catch (NumberFormatException e) {
+            return null;
+        }
+    }
+}

build.gradle

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+package au.com.dius.pactworkshop.consumer;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class ConsumerApplication {
+
+	public static void main(String[] args) {
+		SpringApplication.run(ConsumerApplication.class, args);
+	}
+
+}

consumer/build.gradle

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+package au.com.dius.pactworkshop.consumer;
+
+import java.util.Objects;
+
+public class Product {
+
+    private String id;
+    private String type;
+    private String name;
+    private String version;
+
+    public Product() {
+    }
+
+    public Product(String id,
+                   String type,
+                   String name,
+                   String version) {
+        this.id = id;
+        this.type = type;
+        this.name = name;
+        this.version = version;
+    }
+
+    public String getId() {
+        return id;
+    }
+
+    public void setId(String id) {
+        this.id = id;
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getVersion() {
+        return version;
+    }
+
+    public void setVersion(String version) {
+        this.version = version;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Product product = (Product) o;
+        return Objects.equals(id, product.id) &&
+                Objects.equals(type, product.type) &&
+                Objects.equals(name, product.name) &&
+                Objects.equals(version, product.version);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id, type, name, version);
+    }
+
+    @Override
+    public String toString() {
+        return "Product{" +
+                "id='" + id + '\'' +
+                ", type='" + type + '\'' +
+                ", name='" + name + '\'' +
+                ", version='" + version + '\'' +
+                '}';
+    }
+}

consumer/src/main/java/au/com/dius/pactworkshop/consumer/ConsoleInterface.java

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+package au.com.dius.pactworkshop.consumer;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.ParameterizedTypeReference;
+import org.springframework.http.HttpMethod;
+import org.springframework.stereotype.Service;
+import org.springframework.web.client.RestTemplate;
+
+import java.util.List;
+
+@Service
+public class ProductService {
+
+    private final RestTemplate restTemplate;
+
+    @Autowired
+    public ProductService(RestTemplate restTemplate) {
+        this.restTemplate = restTemplate;
+    }
+
+    public List<Product> getAllProducts() {
+        return restTemplate.exchange("/products",
+                HttpMethod.GET,
+                null,
+                new ParameterizedTypeReference<List<Product>>(){}).getBody();
+    }
+
+    public Product getProduct(String id) {
+        return restTemplate.getForEntity("/products/{id}", Product.class, id).getBody();
+    }
+}

consumer/src/main/java/au/com/dius/pactworkshop/consumer/ConsumerApplication.java

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+package au.com.dius.pactworkshop.consumer;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.boot.web.client.RestTemplateBuilder;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.client.RestTemplate;
+
+@Configuration
+public class ProductServiceConfig {
+
+    @Bean
+    RestTemplate productRestTemplate(@Value("${provider.port:8085}") int port) {
+        return new RestTemplateBuilder().rootUri(String.format("http://localhost:%d", port)).build();
+    }
+}

consumer/src/main/java/au/com/dius/pactworkshop/consumer/Product.java

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+spring.main.web-application-type=NONE