Pact Maven + Springboot + JUnit5 workshop

Introduction

This workshop is aimed at demonstrating core features and benefits of contract testing with Pact.

Whilst contract testing can be applied retrospectively to systems, we will follow the consumer driven contracts approach in this workshop - where a new consumer and provider are created in parallel to evolve a service over time, especially where there is some uncertainty with what is to be built.

This workshop should take from 1 to 2 hours, depending on how deep you want to go into each topic.

Workshop outline:

step 1: create consumer: Create our consumer before the Provider API even exists
step 2: unit test: Write a unit test for our consumer
step 3: pact test: Write a Pact test for our consumer
step 4: pact verification: Verify the consumer pact with the Provider API
step 5: fix consumer: Fix the consumer's bad assumptions about the Provider
step 6: pact test: Write a pact test for 404 (missing User) in consumer
step 7: provider states: Update API to handle 404 case
step 8: pact test: Write a pact test for the 401 case
step 9: pact test: Update API to handle 401 case
step 10: request filters: Fix the provider to support the 401 case
step 11: pact broker: Implement a broker workflow for integration with CI/CD

NOTE: Each step is tied to, and must be run within, a git branch, allowing you to progress through each stage incrementally. For example, to move to step 2 run the following: git checkout step2

Learning objectives

If running this as a team workshop format, you may want to take a look through the learning objectives.

Requirements

JDK 8 or above
Maven 3
Docker for step 11

Scenario

There are two components in scope for our workshop.

Product Catalog website. It provides an interface to query the Product service for product information.
Product Service (Provider). Provides useful things about products, such as listing all products and getting the details of an individual product.

<<<<<<< HEAD

Start

Start at step 1

Step 1 - Simple Consumer calling Provider

We need to first create an HTTP client to make the calls to our provider service:

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:

You can see the service client interface we created in consumer/src/main/java/io/pact/workshop/product_catalogue/clients/ProductServiceClient.java:

@Service
public class ProductServiceClient {
  @Autowired
  private RestTemplate restTemplate;

  @Value("${serviceClients.products.baseUrl}")
  private String baseUrl;

  public ProductServiceResponse fetchProducts() {
    return restTemplate.getForObject(baseUrl + "/products", ProductServiceResponse.class);
  }

  public Product fetchProductById(long id) {
    return restTemplate.getForObject(baseUrl + "/products/" + id, Product.class);
  }
}

After forking or cloning the repository, we need to build the app and install the dependencies. Run the following in the consumer sub-directory:

consumer ❯ ./mvnw verify

We can run the app with

consumer ❯ java -jar target/product-catalogue-0.0.1-SNAPSHOT.jar

Accessing the URL for the app in the browser gives us a 500 error page as the downstream service is not running. You will also see an exception in the Springboot console output.

 I/O error on GET request for "http://localhost:9000/products": Connection refused

Move on to step 2

Step 2 - Client Tested but integration fails

Now let's create a basic test for our API client. We're going to check 2 things:

That our client code hits the expected endpoint
That the response is marshalled into an object that is usable, with the correct ID

You can see the client interface test we created in consumer/src/test/java/io/pact/workshop/product_catalogue/clients/ProductServiceClientTest.java:

  @Test
  void getProductById(@Wiremock WireMockServer server, @WiremockUri String uri) {
      productServiceClient.setBaseUrl(uri);
      server.stubFor(
          get(urlPathEqualTo("/products/10"))
              .willReturn(aResponse()
              .withStatus(200)
              .withBody("{\n" +
                  "            \"id\": 50,\n" +
                  "            \"type\": \"CREDIT_CARD\",\n" +
                  "            \"name\": \"28 Degrees\",\n" +
                  "            \"version\": \"v1\"\n" +
                  "        }\n")
              .withHeader("Content-Type", "application/json"))
      );
    
      Product product = productServiceClient.getProductById(10);
      assertThat(product, is(equalTo(new Product(10L, "28 Degrees", "CREDIT_CARD", "v1"))));
  }

Let's run this test and see it all pass:

consumer ❯ ./mvnw verify
[INFO] Scanning for projects...
[INFO] 
[INFO] -----------------< io.pact.workshop:product-catalogue >-----------------
[INFO] Building product-catalogue 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven-resources-plugin:3.2.0:resources (default-resources) @ product-catalogue ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Using 'UTF-8' encoding to copy filtered properties files.
[INFO] Copying 1 resource
[INFO] Copying 0 resource
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ product-catalogue ---
[INFO] Nothing to compile - all classes are up to date
[INFO] 
[INFO] --- maven-resources-plugin:3.2.0:testResources (default-testResources) @ product-catalogue ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Using 'UTF-8' encoding to copy filtered properties files.
[INFO] skip non existing resourceDirectory /home/ronald/Development/Projects/Pact/pact-workshop-Maven-Springboot-JUnit5/consumer/src/test/resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ product-catalogue ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 1 source file to /home/ronald/Development/Projects/Pact/pact-workshop-Maven-Springboot-JUnit5/consumer/target/test-classes
[INFO] 
[INFO] --- maven-surefire-plugin:2.22.2:test (default-test) @ product-catalogue ---
[INFO] 
[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------
[INFO] Running io.pact.workshop.product_catalogue.clients.products.ProductServiceClientTest

<<< Omitted lots of logs >>>

[INFO] Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 1.952 s - in io.pact.workshop.product_catalogue.clients.products.ProductServiceClientTest
2021-02-25 13:37:46.510  INFO 25640 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 2, Failures: 0, Errors: 0, Skipped: 0
[INFO] 
[INFO] 
[INFO] --- maven-jar-plugin:3.2.0:jar (default-jar) @ product-catalogue ---
[INFO] 
[INFO] --- spring-boot-maven-plugin:2.4.3:repackage (repackage) @ product-catalogue ---
[INFO] Replacing main artifact with repackaged archive
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  4.535 s
[INFO] Finished at: 2021-02-25T13:37:47+11:00
[INFO] ------------------------------------------------------------------------

If you encounter failing tests after running ./mvnw verify, make sure that the current branch is step2.

Meanwhile, our provider team has started building out their API in parallel. Let's run our website against our provider (you'll need two terminals to do this):

# Terminal 1
consumer ❯ mvn spring-boot:run

<<< Omitted >>>

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.4.3)

2021-02-25 13:46:36.835  INFO 26565 --- [           main] i.p.w.product_catalogue.Application      : Starting Application using Java 1.8.0_265 on ronald-P95xER with PID 26565 (/home/ronald/Development/Projects/Pact/pact-workshop-Maven-Springboot-JUnit5/consumer/target/classes started by ronald in /home/ronald/Development/Projects/Pact/pact-workshop-Maven-Springboot-JUnit5/consumer)
2021-02-25 13:46:36.836  INFO 26565 --- [           main] i.p.w.product_catalogue.Application      : No active profile set, falling back to default profiles: default
2021-02-25 13:46:37.274  INFO 26565 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2021-02-25 13:46:37.279  INFO 26565 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2021-02-25 13:46:37.279  INFO 26565 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.43]
2021-02-25 13:46:37.303  INFO 26565 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2021-02-25 13:46:37.303  INFO 26565 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 441 ms
2021-02-25 13:46:37.405  INFO 26565 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2021-02-25 13:46:37.481  INFO 26565 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2021-02-25 13:46:37.486  INFO 26565 --- [           main] i.p.w.product_catalogue.Application      : Started Application in 0.866 seconds (JVM running for 1.051)

# Terminal 2
provider ❯  mvn spring-boot:run

<<< Omitted >>>

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.4.3)

2021-02-25 16:06:08.671  INFO 40129 --- [           main] i.p.w.product_service.Application        : Starting Application using Java 1.8.0_265 on ronald-P95xER with PID 40129 (/home/ronald/Development/Projects/Pact/pact-workshop-Maven-Springboot-JUnit5/provider/target/classes started by ronald in /home/ronald/Development/Projects/Pact/pact-workshop-Maven-Springboot-JUnit5/provider)
2021-02-25 16:06:08.673  INFO 40129 --- [           main] i.p.w.product_service.Application        : No active profile set, falling back to default profiles: default
2021-02-25 16:06:08.990  INFO 40129 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data JPA repositories in DEFAULT mode.
2021-02-25 16:06:09.013  INFO 40129 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 18 ms. Found 1 JPA repository interfaces.
2021-02-25 16:06:09.159  INFO 40129 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.ws.config.annotation.DelegatingWsConfiguration' of type [org.springframework.ws.config.annotation.DelegatingWsConfiguration$$EnhancerBySpringCGLIB$$c6a6464a] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2021-02-25 16:06:09.189  INFO 40129 --- [           main] .w.s.a.s.AnnotationActionEndpointMapping : Supporting [WS-Addressing August 2004, WS-Addressing 1.0]
2021-02-25 16:06:09.344  INFO 40129 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 9000 (http)
2021-02-25 16:06:09.349  INFO 40129 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2021-02-25 16:06:09.349  INFO 40129 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.43]
2021-02-25 16:06:09.382  INFO 40129 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2021-02-25 16:06:09.382  INFO 40129 --- [           main] w.s.c.ServletWebServerApplicationContext : Root WebApplicationContext: initialization completed in 684 ms
2021-02-25 16:06:09.469  INFO 40129 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2021-02-25 16:06:09.525  INFO 40129 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
2021-02-25 16:06:09.549  INFO 40129 --- [           main] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [name: default]
2021-02-25 16:06:09.569  INFO 40129 --- [           main] org.hibernate.Version                    : HHH000412: Hibernate ORM core version 5.4.28.Final
2021-02-25 16:06:09.621  INFO 40129 --- [           main] o.hibernate.annotations.common.Version   : HCANN000001: Hibernate Commons Annotations {5.1.2.Final}
2021-02-25 16:06:09.702  INFO 40129 --- [           main] org.hibernate.dialect.Dialect            : HHH000400: Using dialect: org.hibernate.dialect.H2Dialect
2021-02-25 16:06:09.954  INFO 40129 --- [           main] o.h.e.t.j.p.i.JtaPlatformInitiator       : HHH000490: Using JtaPlatform implementation: [org.hibernate.engine.transaction.jta.platform.internal.NoJtaPlatform]
2021-02-25 16:06:09.958  INFO 40129 --- [           main] j.LocalContainerEntityManagerFactoryBean : Initialized JPA EntityManagerFactory for persistence unit 'default'
2021-02-25 16:06:10.093  WARN 40129 --- [           main] JpaBaseConfiguration$JpaWebConfiguration : spring.jpa.open-in-view is enabled by default. Therefore, database queries may be performed during view rendering. Explicitly configure spring.jpa.open-in-view to disable this warning
2021-02-25 16:06:10.149  INFO 40129 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2021-02-25 16:06:10.259  INFO 40129 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 9000 (http) with context path ''
2021-02-25 16:06:10.265  INFO 40129 --- [           main] i.p.w.product_service.Application        : Started Application in 1.812 seconds (JVM running for 2.0)
2021-02-25 16:06:11.833  INFO 40129 --- [nio-9000-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-02-25 16:06:11.833  INFO 40129 --- [nio-9000-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2021-02-25 16:06:11.834  INFO 40129 --- [nio-9000-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 1 ms

You should now see a screen showing 3 different products. There is a Details ... link which should display detailed product information.

Let's see what happens!

Doh! We are getting 500 everytime we try to view detailed product information. On closer inspection, we can see a 404 from the Product Service in the logs.

HttpClientErrorException$NotFound: 404 : [{"timestamp":"2021-02-25T05:27:51.264+00:00","status":404,"error":"Not Found","message":"","path":"/products/9"}]]

The issue is that the provider only knows about /product/{id} and /products.

We need to have a conversation about what the endpoint should be, but first...

Move on to step 3

Step 3 - Pact to the rescue

Unit tests are written and executed in isolation of any other services. When we write tests for code that talk to other services, they are built on trust that the contracts are upheld. There is no way to validate that the consumer and provider can communicate correctly.

An integration contract test is a test at the boundary of an external service verifying that it meets the contract expected by a consuming service — Martin Fowler

Adding contract tests via Pact would have highlighted the /product/{id} endpoint was incorrect.

Let us add Pact to the project and write a consumer pact test for the GET /products/{id} endpoint.

Provider states is an important concept of Pact that we need to introduce. These states help define the state that the provider should be in for specific interactions. For the moment, we will initially be testing the following states:

product with ID 10 exists
products exist

The consumer can define the state of an interaction using the given property.

Pact test consumer/src/test/java/io/pact/workshop/product_catalogue/clients/ProductServiceClientPactTest.java:

@SpringBootTest
@ExtendWith(PactConsumerTestExt.class)
@PactTestFor(providerName = "ProductService")
class ProductServiceClientPactTest {
  @Autowired
  private ProductServiceClient productServiceClient;

  @Pact(consumer = "ProductCatalogue")
  public RequestResponsePact allProducts(PactDslWithProvider builder) {
    return builder
      .given("products exists")
      .uponReceiving("get all products")
      .path("/products")
      .willRespondWith()
      .status(200)
      .body(
        new PactDslJsonBody()
          .minArrayLike("products", 1, 2)
          .integerType("id", 9L)
          .stringType("name", "Gem Visa")
          .stringType("type", "CREDIT_CARD")
          .closeObject()
          .closeArray()
      )
      .toPact();
  }

  @Pact(consumer = "ProductCatalogue")
  public RequestResponsePact singleProduct(PactDslWithProvider builder) {
    return builder
      .given("product with ID 10 exists", "id", 10)
      .uponReceiving("get product with ID 10")
      .path("/products/10")
      .willRespondWith()
      .status(200)
      .body(
        new PactDslJsonBody()
          .integerType("id", 10L)
          .stringType("name", "28 Degrees")
          .stringType("type", "CREDIT_CARD")
          .stringType("code", "CC_001")
          .stringType("version", "v1")
      )
      .toPact();
  }

  @Test
  @PactTestFor(pactMethod = "allProducts", port="9999")
  void testAllProducts(MockServer mockServer) throws IOException {
    productServiceClient.setBaseUrl(mockServer.getUrl());
    List<Product> products = productServiceClient.fetchProducts().getProducts();
    assertThat(products, hasSize(2));
    assertThat(products.get(0), is(equalTo(new Product(9L, "Gem Visa", "CREDIT_CARD", null, null))));
  }

  @Test
  @PactTestFor(pactMethod = "singleProduct", port="9999")
  void testSingleProduct(MockServer mockServer) throws IOException {
    Product product = productServiceClient.getProductById(10L);
    assertThat(product, is(equalTo(new Product(10L, "28 Degrees", "CREDIT_CARD", "v1", "CC_001"))));
  }
}

These tests starts a mock server on a random port that acts as our provider service. To get this to work we update the URL in the ProductServiceClient to point to the mock server that Pact provides for the test.

Running this test also passes, but it creates a pact file which we can use to validate our assumptions on the provider side, and have conversation around.

consumer ❯ ./mvnw verify
[INFO] Scanning for projects...
[INFO] 
[INFO] -----------------< io.pact.workshop:product-catalogue >-----------------
[INFO] Building product-catalogue 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven-resources-plugin:3.2.0:resources (default-resources) @ product-catalogue ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Using 'UTF-8' encoding to copy filtered properties files.
[INFO] Copying 1 resource
[INFO] Copying 6 resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ product-catalogue ---
[INFO] Nothing to compile - all classes are up to date
[INFO] 
[INFO] --- maven-resources-plugin:3.2.0:testResources (default-testResources) @ product-catalogue ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Using 'UTF-8' encoding to copy filtered properties files.
[INFO] skip non existing resourceDirectory /home/ronald/Development/Projects/Pact/pact-workshop-Maven-Springboot-JUnit5/consumer/src/test/resources
[INFO] 
[INFO] --- maven-compiler-plugin:3.8.1:testCompile (default-testCompile) @ product-catalogue ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 2 source files to /home/ronald/Development/Projects/Pact/pact-workshop-Maven-Springboot-JUnit5/consumer/target/test-classes
[INFO] 
[INFO] --- maven-surefire-plugin:2.22.2:test (default-test) @ product-catalogue ---
[INFO] 
[INFO] -------------------------------------------------------
[INFO]  T E S T S
[INFO] -------------------------------------------------------

<<< Omitted >>>

[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 4, Failures: 0, Errors: 0, Skipped: 0
[INFO] 
[INFO] 
[INFO] --- maven-jar-plugin:3.2.0:jar (default-jar) @ product-catalogue ---
[INFO] Building jar: /home/ronald/Development/Projects/Pact/pact-workshop-Maven-Springboot-JUnit5/consumer/target/product-catalogue-0.0.1-SNAPSHOT.jar
[INFO] 
[INFO] --- spring-boot-maven-plugin:2.4.3:repackage (repackage) @ product-catalogue ---
[INFO] Replacing main artifact with repackaged archive
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  6.013 s
[INFO] Finished at: 2021-02-26T09:43:03+11:00
[INFO] ------------------------------------------------------------------------

A pact file should have been generated in consumer/target/pacts/ProductCatalogue-ProductService.json

NOTE: even if the API client had been graciously provided for us by our Provider Team, it doesn't mean that we shouldn't write contract tests - because the version of the client we have may not always be in sync with the deployed API - and also because we will write tests on the output appropriate to our specific needs.

Move on to step 4

Step 4 - Verify the provider

We will need to copy the Pact contract file that was produced from the consumer test into the Provider module. This will help us verify that the provider can meet the requirements as set out in the contract.

Copy the contract located in consumer/target/pacts/ProductCatalogue-ProductService.json to provider/pacts/ProductCatalogue-ProductService.json.

Now let's make a start on writing a Pact test to validate the consumer contract:

In provider/src/test/java/io/pact/workshop/product_service/PactVerificationTest.java:

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
@Provider("ProductService")
@PactFolder("pacts")
@IgnoreMissingStateChange
public class PactVerificationTest {
  @LocalServerPort
  private int port;

  @Autowired
  private ProductRepository productRepository;

  @BeforeEach
  void setup(PactVerificationContext context) {
    context.setTarget(new HttpTestTarget("localhost", port));
  }

  @TestTemplate
  @ExtendWith(PactVerificationInvocationContextProvider.class)
  void pactVerificationTestTemplate(PactVerificationContext context) {
    context.verifyInteraction();
  }
}

This is a Springboot test that starts the app on a random port, and then injects the port into the test class. We then setup the test context using some annotations on the test class that tells the Pact framework who the provider is and where the pact files are. We also set the test target to point to the running app.

We now need to validate the pact generated by the consumer is valid by running the test, which should fail:

provider ❯ ./mvnw verify

<<< Omitted >>>

1) Verifying a pact between ProductCatalogue and ProductService - get product with ID 10: has status code 200

    1.1) status: expected status of 200 but was 404

    1.2) body: $ Expected code='CC_001' but was missing

        {
        -  "code": "CC_001",
        -  "id": 10,
        -  "name": "28 Degrees",
        -  "type": "CREDIT_CARD",
        -  "version": "v1"
        +  "timestamp": "2021-02-26T02:50:41.293+00:00",
        +  "status": 404,
        +  "error": "Not Found",
        +  "message": "",
        +  "path": "/products/10"
        }

<<< Omitted >>>

The test has failed, as the expected path /products/{id} is returning 404. We incorrectly believed our provider was following a RESTful design, but the authors were too lazy to implement a better routing solution 🤷🏻‍♂️.

The correct endpoint which the consumer should call is /product/{id}.

Move on to step 5

Step 5 - Back to the client we go

We now need to update the consumer client and tests to hit the correct product path.

First, we need to update the GET route for the client:

In consumer/src/main/java/io/pact/workshop/product_catalogue/clients/ProductServiceClient.java:

  public Product getProductById(long id) {
    return restTemplate.getForObject(baseUrl + "/product/" + id, Product.class);
  }

Then we need to update the Pact test ID 10 exists to use the correct endpoint in path.

In consumer/src/test/java/io/pact/workshop/product_catalogue/clients/ProductServiceClientPactTest.java:

  @Pact(consumer = "ProductCatalogue")
  public RequestResponsePact singleProduct(PactDslWithProvider builder) {
    return builder
      .given("product with ID 10 exists", "id", 10)
      .uponReceiving("get product with ID 10")
        .path("/product/10")
      .willRespondWith()
        .status(200)
        .body(
          new PactDslJsonBody()
            .integerType("id", 10L)
            .stringType("name", "28 Degrees")
            .stringType("type", "CREDIT_CARD")
            .stringType("code", "CC_001")
            .stringType("version", "v1")
        )
      .toPact();
  }

Let's run and generate an updated pact file on the consumer:

consumer ❯ ./mvnw verify

<<< Omitted >>>

[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 4, Failures: 0, Errors: 0, Skipped: 0
[INFO] 
[INFO] 
[INFO] --- maven-jar-plugin:3.2.0:jar (default-jar) @ product-catalogue ---
[INFO] Building jar: /home/ronald/Development/Projects/Pact/pact-workshop-Maven-Springboot-JUnit5/consumer/target/product-catalogue-0.0.1-SNAPSHOT.jar
[INFO] 
[INFO] --- spring-boot-maven-plugin:2.4.3:repackage (repackage) @ product-catalogue ---
[INFO] Replacing main artifact with repackaged archive
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

Now we run the provider tests again with the updated contract

Copy the updated contract located in consumer/target/pacts/ProductCatalogue-ProductService.json to provider/pacts.

Run the command:

provider ❯ ./mvnw verify

<<< Omitted >>>

Verifying a pact between ProductCatalogue and ProductService
  [Using File pacts/ProductCatalogue-ProductService.json]
  Given product with ID 10 exists
  get product with ID 10
2021-02-26 13:11:45.229  INFO 96199 --- [o-auto-1-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-02-26 13:11:45.229  INFO 96199 --- [o-auto-1-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2021-02-26 13:11:45.230  INFO 96199 --- [o-auto-1-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 1 ms
    returns a response which
      has status code 200 (OK)
      has a matching body (OK)
2021-02-26 13:11:45.356  WARN 96199 --- [           main] a.c.d.p.p.DefaultTestResultAccumulator   : Not all of the 2 were verified. The following were missing:
2021-02-26 13:11:45.356  WARN 96199 --- [           main] a.c.d.p.p.DefaultTestResultAccumulator   :     get all products
2021-02-26 13:11:45.366  INFO 96199 --- [           main] p.j.PactVerificationStateChangeExtension : Invoking state change method 'products exists':SETUP

Verifying a pact between ProductCatalogue and ProductService
  [Using File pacts/ProductCatalogue-ProductService.json]
  Given products exists
  get all products
    returns a response which
      has status code 200 (OK)
      has a matching body (OK)
2021-02-26 13:11:45.485  WARN 96199 --- [           main] a.c.d.p.p.DefaultTestResultAccumulator   : Skipping publishing of verification results as it has been disabled (pact.verifier.publishResults is not 'true')
[INFO] Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 4.573 s - in io.pact.workshop.product_service.PactVerificationTest
2021-02-26 13:11:45.527  INFO 96199 --- [extShutdownHook] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'
2021-02-26 13:11:45.527  INFO 96199 --- [extShutdownHook] j.LocalContainerEntityManagerFactoryBean : Closing JPA EntityManagerFactory for persistence unit 'default'
2021-02-26 13:11:45.528  INFO 96199 --- [extShutdownHook] .SchemaDropperImpl$DelayedDropActionImpl : HHH000477: Starting delayed evictData of schema as part of SessionFactory shut-down'
2021-02-26 13:11:45.532  INFO 96199 --- [extShutdownHook] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown initiated...
2021-02-26 13:11:45.534  INFO 96199 --- [extShutdownHook] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Shutdown completed.
[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 2, Failures: 0, Errors: 0, Skipped: 0
[INFO]

Yay - green ✅!

Move on to step 6

Step 6 - Consumer updates contract for missing products

We're now going to add 2 more scenarios for the contract

What happens when we make a call for a product that doesn't exist? We assume we'll get a 404.
What happens when we make a call for getting all products but none exist at the moment? We assume a 200 with an empty array.

Let's write a test for these scenarios, and then generate an updated pact file.

In consumer/src/test/java/io/pact/workshop/product_catalogue/clients/ProductServiceClientPactTest.java:

  @Pact(consumer = "ProductCatalogue")
  public RequestResponsePact noProducts(PactDslWithProvider builder) {
    return builder
      .given("no products exists")
      .uponReceiving("get all products")
        .path("/products")
      .willRespondWith()
        .status(200)
        .body(
          new PactDslJsonBody().array("products")
        )
      .toPact();
  }

  @Test
  @PactTestFor(pactMethod = "noProducts")
  void testNoProducts(MockServer mockServer) {
    productServiceClient.setBaseUrl(mockServer.getUrl());
    ProductServiceResponse products = productServiceClient.fetchProducts();
    assertThat(products.getProducts(), hasSize(0));
  }

  @Pact(consumer = "ProductCatalogue")
  public RequestResponsePact singleProductNotExists(PactDslWithProvider builder) {
    return builder
      .given("product with ID 10 does not exist", "id", 10)
      .uponReceiving("get product with ID 10")
        .path("/product/10")
      .willRespondWith()
        .status(404)
      .toPact();
  }

  @Test
  @PactTestFor(pactMethod = "singleProductNotExists")
  void testSingleProductNotExists(MockServer mockServer) {
    productServiceClient.setBaseUrl(mockServer.getUrl());
    try {
      productServiceClient.getProductById(10L);
      fail("Expected service call to throw an exception");
    } catch (HttpClientErrorException ex) {
      assertThat(ex.getMessage(), containsString("404 Not Found"));
    }
  }

Notice that our new tests look almost identical to our previous tests, and only differ on the expectations of the response - the HTTP request expectations are exactly the same.

consumer ❯ ./mvnw verify

<<< Omitted >>>

[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 6, Failures: 0, Errors: 0, Skipped: 0
[INFO] 
[INFO] 
[INFO] --- maven-jar-plugin:3.2.0:jar (default-jar) @ product-catalogue ---
[INFO] Building jar: /home/ronald/Development/Projects/Pact/pact-workshop-Maven-Springboot-JUnit5/consumer/target/product-catalogue-0.0.1-SNAPSHOT.jar
[INFO] 
[INFO] --- spring-boot-maven-plugin:2.4.3:repackage (repackage) @ product-catalogue ---
[INFO] Replacing main artifact with repackaged archive
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

What does our provider have to say about this new test. Again, copy the updated pact file into the provider's pact directory and run the command:

provider ❯ ./mvnw verify

<<< Omitted >>>

Verifying a pact between ProductCatalogue and ProductService
  [Using File pacts/ProductCatalogue-ProductService.json]
  Given no products exists
  get all products
2021-02-26 13:45:27.930  INFO 100121 --- [o-auto-1-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-02-26 13:45:27.932  INFO 100121 --- [o-auto-1-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2021-02-26 13:45:27.934  INFO 100121 --- [o-auto-1-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 1 ms
    returns a response which
      has status code 200 (OK)
      has a matching body (FAILED)

Failures:

1) Verifying a pact between ProductCatalogue and ProductService - get all products has a matching body

    1.1) body: $.products Expected an empty List but received [{"code":"CC_01_VISA","id":9,"name":"Gem Visa","type":"CREDIT_CARD","version":"v1"},{"code":"CC_02_OTH","id":10,"name":"28 Degrees","type":"CREDIT_CARD","version":"v1"},{"code":"LN_PERS_01","id":11,"name":"MyFlexiPay","type":"PERSONAL_LOAN","version":"v2"}]

        [
        -
        +  {
        +    "id": 9,
        +    "name": "Gem Visa",
        +    "type": "CREDIT_CARD",
        +    "version": "v1",
        +    "code": "CC_01_VISA"
        +  },
        +  {
        +    "id": 10,
        +    "name": "28 Degrees",
        +    "type": "CREDIT_CARD",
        +    "version": "v1",
        +    "code": "CC_02_OTH"
        +  },
        +  {
        +    "id": 11,
        +    "name": "MyFlexiPay",
        +    "type": "PERSONAL_LOAN",
        +    "version": "v2",
        +    "code": "LN_PERS_01"
        +  }
        ]



2021-02-26 13:45:28.460  WARN 100121 --- [           main] a.c.d.p.p.DefaultTestResultAccumulator   : Not all of the 4 were verified. The following were missing:
2021-02-26 13:45:28.460  WARN 100121 --- [           main] a.c.d.p.p.DefaultTestResultAccumulator   :     get product with ID 10
2021-02-26 13:45:28.461  WARN 100121 --- [           main] a.c.d.p.p.DefaultTestResultAccumulator   :     get product with ID 10
2021-02-26 13:45:28.461  WARN 100121 --- [           main] a.c.d.p.p.DefaultTestResultAccumulator   :     get all products
2021-02-26 13:45:28.463  WARN 100121 --- [           main] p.j.PactVerificationStateChangeExtension : Did not find a test class method annotated with @State("no products exists") 
for Interaction "get all products" 
with Consumer "ProductCatalogue"
2021-02-26 13:45:28.530  WARN 100121 --- [           main] p.j.PactVerificationStateChangeExtension : Did not find a test class method annotated with @State("product with ID 10 does not exist") 
for Interaction "get product with ID 10" 
with Consumer "ProductCatalogue"

Verifying a pact between ProductCatalogue and ProductService
  [Using File pacts/ProductCatalogue-ProductService.json]
  Given product with ID 10 does not exist
  get product with ID 10
    returns a response which
      has status code 404 (FAILED)
      has a matching body (OK)

Failures:

1) Verifying a pact between ProductCatalogue and ProductService - get product with ID 10: has status code 404

    1.1) status: expected status of 404 but was 200

We expected this failure, because the product we are requesting does in fact exist! What we want to test for, is what happens if there is a different state on the Provider. This is what is referred to as "Provider states", and how Pact gets around test ordering and related issues.

We could resolve this by updating our consumer test to use a known non-existent product, but it's worth understanding how Provider states work more generally.

Move on to step 7

Step 7 - Adding the missing states

We need to update our provider code to deal with missing products and send a 404 response. However, our test data fixture also has product ID 10 and 11 in our database.

In this step, we will add some state handlers to our provider Pact verification test, which will update the state of our data store depending on which states the consumers require.

States are invoked prior to the actual test function is invoked. For each interaction in a pact file, the order of execution is as follows:

BeforeEach -> StateHandler (setup) -> RequestFilter -> Execute Provider Test -> StateHandler (teardown) -> AfterEach

We're going to add handlers for all our states:

products exist
no products exist
product with ID 10 exists
product with ID 10 does not exist

Let's open up our provider Pact verification test in provider/src/test/java/io/pact/workshop/product_service/PactVerificationTest.java:

  @State(value = "products exists", action = StateChangeAction.SETUP)
  void productsExists() {
    productRepository.deleteAll();
    productRepository.saveAll(Arrays.asList(
      new Product(100L, "Test Product 1", "CREDIT_CARD", "v1", "CC_001"),
      new Product(200L, "Test Product 2", "CREDIT_CARD", "v1", "CC_002"),
      new Product(300L, "Test Product 3", "PERSONAL_LOAN", "v1", "PL_001"),
      new Product(400L, "Test Product 4", "SAVINGS", "v1", "SA_001")
    ));
  }

  @State(value = "no products exists", action = StateChangeAction.SETUP)
  void noProductsExist() {
    productRepository.deleteAll();
  }

  @State(value = "product with ID 10 exists", action = StateChangeAction.SETUP)
  void productExists(Map<String, Object> params) {
    long productId = ((Number) params.get("id")).longValue();
    Optional<Product> product = productRepository.findById(productId);
    if (!product.isPresent()) {
      productRepository.save(new Product(productId, "Product", "TYPE", "v1", "001"));
    }
  }

  @State(value = "product with ID 10 does not exist", action = StateChangeAction.SETUP)
  void productNotExist(Map<String, Object> params) {
    long productId = ((Number) params.get("id")).longValue();
    Optional<Product> product = productRepository.findById(productId);
    if (product.isPresent()) {
      productRepository.deleteById(productId);
    }
  }

Let's see how we go now:

provider ❯ ./mvnw verify

<<< Omitted >>>

[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 4, Failures: 0, Errors: 0, Skipped: 0
[INFO] 
[INFO] 
[INFO] --- maven-jar-plugin:3.2.0:jar (default-jar) @ product-service ---
[INFO] Building jar: /home/ronald/Development/Projects/Pact/pact-workshop-Maven-Springboot-JUnit5/provider/target/product-service-1.0-SNAPSHOT.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

NOTE: The states are not necessarily a 1 to 1 mapping with the consumer contract tests. You can reuse states amongst different tests. In this scenario we could have used no products exist for both tests which would have equally been valid.

Move on to step 8

Step 8 - Authorization

It turns out that not everyone should be able to use the API. After a discussion with the team, it was decided that a time-bound bearer token would suffice. The token must be base64 encoded format of a timestamp value and within 1 hour of the current time.

In the case a valid bearer token is not provided, we expect a 401. Let's update the consumer to pass the bearer token, and capture this new 401 scenario.

In consumer/src/main/java/io/pact/workshop/product_catalogue/clients/ProductServiceClient.java:

@Service
public class ProductServiceClient {
  @Autowired
  private RestTemplate restTemplate;

  @Value("${serviceClients.products.baseUrl}")
  private String baseUrl;

  public ProductServiceResponse fetchProducts() {
    return callApi("/products", ProductServiceResponse.class);
  }

  public Product getProductById(long id) {
    return callApi("/product/" + id, Product.class);
  }

  public String getBaseUrl() {
    return baseUrl;
  }

  public void setBaseUrl(String baseUrl) {
    this.baseUrl = baseUrl;
  }

  private <T> T callApi(String path, Class<T> responseType) {
    HttpHeaders headers = new HttpHeaders();
    ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES);
    buffer.putLong(System.currentTimeMillis());
    headers.setBearerAuth(Base64.getEncoder().encodeToString(buffer.array()));
    HttpEntity<?> requestEntity = new HttpEntity<>(headers);
    return restTemplate.exchange(baseUrl + path, HttpMethod.GET, requestEntity, responseType).getBody();
  }
}

We add in consumer/src/test/java/io/pact/workshop/product_catalogue/clients/ProductServiceClientPactTest.java:

    .matchHeader("Authorization", "Bearer [a-zA-Z0-9=\\+/]+", "Bearer AAABd9yHUjI=")

to all the interactions and two new interactions:

  @Pact(consumer = "ProductCatalogue")
  public RequestResponsePact noAuthToken(PactDslWithProvider builder) {
    return builder
      .uponReceiving("get all products with no auth token")
        .path("/products")
      .willRespondWith()
        .status(401)
      .toPact();
  }

  @Test
  @PactTestFor(pactMethod = "noAuthToken")
  void testNoAuthToken(MockServer mockServer) {
    productServiceClient.setBaseUrl(mockServer.getUrl());
    try {
      productServiceClient.fetchProducts();
      fail("Expected service call to throw an exception");
    } catch (HttpClientErrorException ex) {
      assertThat(ex.getMessage(), containsString("401 Unauthorized"));
    }
  }

  @Pact(consumer = "ProductCatalogue")
  public RequestResponsePact noAuthToken2(PactDslWithProvider builder) {
    return builder
      .uponReceiving("get product by ID with no auth token")
        .path("/product/10")
      .willRespondWith()
        .status(401)
      .toPact();
  }

  @Test
  @PactTestFor(pactMethod = "noAuthToken2")
  void testNoAuthToken2(MockServer mockServer) {
    productServiceClient.setBaseUrl(mockServer.getUrl());
    try {
      productServiceClient.getProductById(10L);
      fail("Expected service call to throw an exception");
    } catch (HttpClientErrorException ex) {
      assertThat(ex.getMessage(), containsString("401 Unauthorized"));
    }
  }

Then re-run the Pact test to generate a new Pact file.

Let's test the provider. Copy the updated pact file into the provider's pact directory and run the tests:

provider ❯ ./mvnw verify

<<< Omitted >>>

[ERROR] Tests run: 6, Failures: 2, Errors: 0, Skipped: 0, Time elapsed: 4.631 s <<< FAILURE! - in io.pact.workshop.product_service.PactVerificationTest
[ERROR] pactVerificationTestTemplate{PactVerificationContext}[1]  Time elapsed: 0.487 s  <<< FAILURE!
java.lang.AssertionError: 
ProductCatalogue - Upon get all products with no auth token 
Failures:

1) Verifying a pact between ProductCatalogue and ProductService - get all products with no auth token: has status code 401

    1.1) status: expected status of 401 but was 200


        at io.pact.workshop.product_service.PactVerificationTest.pactVerificationTestTemplate(PactVerificationTest.java:41)

[ERROR] pactVerificationTestTemplate{PactVerificationContext}[2]  Time elapsed: 0.027 s  <<< FAILURE!
java.lang.AssertionError: 
ProductCatalogue - Upon get product by ID with no auth token 
Failures:

1) Verifying a pact between ProductCatalogue and ProductService - get product by ID with no auth token: has status code 401

    1.1) status: expected status of 401 but was 200

Now with the most recently added interactions where we are expecting a response of 401, but the provider is not handling any authentication, so we are getting 200...

Move on to step 9

Step 9 - Implement authorisation on the provider

We will setup Spring Security to check the Authorization header and deny the request with 401 if the token is missing or older than 1 hour.

In provider/src/main/java/io/pact/workshop/product_service/config/BearerAuthorizationFilter.java

public class BearerAuthorizationFilter extends OncePerRequestFilter {

  public static final long ONE_HOUR = 60 * 60 * 1000L;

  @Override
  protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
    String header = request.getHeader("Authorization");
    if (tokenValid(header)) {
      SecurityContextHolder.getContext().setAuthentication(new PreAuthenticatedAuthenticationToken("user", header));
      filterChain.doFilter(request, response);
    } else {
      response.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
    }
  }

  private boolean tokenValid(String header) {
    boolean hasBearerToken = StringUtils.isNotEmpty(header) && header.startsWith("Bearer ");
    if (hasBearerToken) {
      String token = header.substring("Bearer ".length());
      ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES);
      buffer.put(Base64.getDecoder().decode(token));
      buffer.flip();
      long timestamp = buffer.getLong();
      return System.currentTimeMillis() - timestamp <= ONE_HOUR;
    } else {
      return false;
    }
  }
}

Let's test this out:

provider ❯ ./mvnw verify

<<< Omitted >>>

[INFO] 
[INFO] Results:
[INFO] 
[ERROR] Failures: 
[ERROR]   PactVerificationTest.pactVerificationTestTemplate:41 ProductCatalogue - Upon get all products 
Failures:

1) Verifying a pact between ProductCatalogue and ProductService - get all products: has status code 200

    1.1) status: expected status of 200 but was 401

    1.2) header: Expected a header 'Content-Type' but was missing

    1.3) body-content-type: Expected a response type of 'application/json' but the actual type was 'null'


[ERROR]   PactVerificationTest.pactVerificationTestTemplate:41 ProductCatalogue - Upon get product with ID 10 
Failures:

1) Verifying a pact between ProductCatalogue and ProductService - get product with ID 10: has status code 404

    1.1) status: expected status of 404 but was 401


[ERROR]   PactVerificationTest.pactVerificationTestTemplate:41 ProductCatalogue - Upon get product with ID 10 
Failures:

1) Verifying a pact between ProductCatalogue and ProductService - get product with ID 10: has status code 200

    1.1) status: expected status of 200 but was 401

    1.2) header: Expected a header 'Content-Type' but was missing

    1.3) body-content-type: Expected a response type of 'application/json' but the actual type was 'null'


[ERROR]   PactVerificationTest.pactVerificationTestTemplate:41 ProductCatalogue - Upon get all products 
Failures:

1) Verifying a pact between ProductCatalogue and ProductService - get all products: has status code 200

    1.1) status: expected status of 200 but was 401

    1.2) header: Expected a header 'Content-Type' but was missing

    1.3) body-content-type: Expected a response type of 'application/json' but the actual type was 'null'


[INFO] 
[ERROR] Tests run: 6, Failures: 4, Errors: 0, Skipped: 0
[INFO] 
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------

Oh, dear. More tests are failing. Can you understand why?

Move on to step 10

Step 10 - Request Filters on the Provider

Because our pact file has static data in it, our bearer token is now out of date, so when Pact verification passes it to the Provider we get a 401. There are multiple ways to resolve this - mocking or stubbing out the authentication component is a common one. In our use case, we are going to use a process referred to as Request Filtering, by modifying the request that gets sent.

NOTE: This is an advanced concept and should be used carefully, as it has the potential to invalidate a contract by bypassing its constraints. See https://github.com/pact-foundation/pact-jvm/blob/master/provider/junit5/README.md#modifying-the-requests-before-they-are-sent for more details on this.

The approach we are going to take to inject the header is as follows:

If we receive any Authorization header, we override the incoming request with a valid (in time) Authorization header, and continue with whatever call was being made
If we don't receive an Authorization header, we do nothing

NOTE: We are not considering the 403 scenario in this example.

In provider/src/test/java/io/pact/workshop/product_service/PactVerificationTest.java:

  @TestTemplate
  @ExtendWith(PactVerificationInvocationContextProvider.class)
  void pactVerificationTestTemplate(PactVerificationContext context, HttpRequest request) {
    // WARNING: Do not modify anything else on the request, because you could invalidate the contract
    if (request.containsHeader("Authorization")) {
      request.setHeader("Authorization", "Bearer " + generateToken());
    }
    context.verifyInteraction();
  }

  private static String generateToken() {
    ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES);
    buffer.putLong(System.currentTimeMillis());
    return Base64.getEncoder().encodeToString(buffer.array());
  }

We can now run the Provider tests

provider ❯ ./mvnw verify

<<< Omitted >>>

[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 6, Failures: 0, Errors: 0, Skipped: 0
[INFO] 
[INFO] 
[INFO] --- maven-jar-plugin:3.2.0:jar (default-jar) @ product-service ---
[INFO] Building jar: /home/ronald/Development/Projects/Pact/pact-workshop-Maven-Springboot-JUnit5/provider/target/product-service-1.0-SNAPSHOT.jar
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

Move on to step 11

Step 11 - Using a Pact Broker

We've been publishing our pacts from the consumer project by essentially sharing the file system with the provider. But this is not very manageable when you have multiple teams contributing to the code base, and pushing to CI. We can use a Pact Broker to do this instead.

Using a broker simplifies the management of pacts and adds a number of useful features, including some safety enhancements for continuous delivery which we'll see shortly.

In this workshop we will be using the open source Pact broker.

Running the Pact Broker with docker-compose

In the root directory, run:

 ❯ docker-compose up

Publish contracts from consumer

First, in the consumer project we need to tell Pact about our broker. We will use the Pact Maven plugin to manage this.

In consumer/pom.xml:

<build>
  <plugins>
      ...
      <plugin>
          <groupId>au.com.dius.pact.provider</groupId>
          <artifactId>maven</artifactId>
          <version>4.1.17</version>
          <configuration>
            <pactBrokerUrl>http://localhost:9292</pactBrokerUrl>
            <pactBrokerUsername>pact_workshop</pactBrokerUsername>
            <pactBrokerPassword>pact_workshop</pactBrokerPassword>
          </configuration>
      </plugin>
  </plugins>
</build>

And now we can run:

consumer ❯ ./mvnw pact:publish
[INFO] Scanning for projects...
[INFO] 
[INFO] -----------------< io.pact.workshop:product-catalogue >-----------------
[INFO] Building product-catalogue 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven:4.1.17:publish (default-cli) @ product-catalogue ---
Publishing 'ProductCatalogue-ProductService.json' with tags 'prod, test' ... OK
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  0.745 s
[INFO] Finished at: 2021-03-01T09:51:29+11:00
[INFO] ------------------------------------------------------------------------

Have a browse around the broker on http://localhost:9292 (with username/password: pact_workshop/pact_workshop) and see your newly published contract!

Verify contracts on Provider

All we need to do for the provider is update the test where it finds its pacts, from local URLs, to one from a broker. We add a @PactBroker annotation to our test and change it to use the PactVerificationSpringProvider, and then create a test application YAML configuration file with the details of the Pact Broker.

In provider/src/test/java/io/pact/workshop/product_service/PactVerificationTest.java:

@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
@Provider("ProductService")
@PactBroker // <--
public class PactVerificationTest {
  @LocalServerPort
  private int port;

  @Autowired
  private ProductRepository productRepository;

  @BeforeEach
  void setup(PactVerificationContext context) {
    context.setTarget(new HttpTestTarget("localhost", port));
  }

  @TestTemplate
  @ExtendWith(PactVerificationSpringProvider.class) // <--
  void pactVerificationTestTemplate(PactVerificationContext context, HttpRequest request) {
    // WARNING: Do not modify anything else on the request, because you could invalidate the contract
    if (request.containsHeader("Authorization")) {
      request.setHeader("Authorization", "Bearer " + generateToken());
    }
    context.verifyInteraction();
  }

and then create provider/src/test/resources/application.yml:

pactbroker:
  host: localhost
  port: "9292"
  auth:
    username: pact_workshop
    password: pact_workshop

Let's run the provider verification one last time after this change:

provider ❯ ./mvnw verify -Dpact.verifier.publishResults=true -Dpact.provider.version=1.0-SNAPSHOT

<<< Omitted >>>

Verifying a pact between ProductCatalogue (0.0.1-SNAPSHOT) and ProductService

  Notices:
    1) The pact at http://localhost:9292/pacts/provider/ProductService/consumer/ProductCatalogue/pact-version/5565ba9dfe81399a66afbebb620a3d79df43d46a is being verified because it matches the following configured selection criterion: latest pact between a consumer and ProductService

  [from Pact Broker http://localhost:9292/pacts/provider/ProductService/consumer/ProductCatalogue/pact-version/5565ba9dfe81399a66afbebb620a3d79df43d46a/metadata/c1tdW2xdPXRydWUmc1tdW2N2bl09MC4wLjEtU05BUFNIT1Q=]
  get all products with no auth token
2021-03-01 10:32:06.625  INFO 32791 --- [o-auto-1-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
2021-03-01 10:32:06.625  INFO 32791 --- [o-auto-1-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
2021-03-01 10:32:06.625  INFO 32791 --- [o-auto-1-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 0 ms
    returns a response which
      has status code 401 (OK)
      has a matching body (OK)
      
<<< Omitted >>>

[INFO] 
[INFO] Results:
[INFO] 
[INFO] Tests run: 6, Failures: 0, Errors: 0, Skipped: 0
[INFO] 
[INFO] 
[INFO] --- maven-jar-plugin:3.2.0:jar (default-jar) @ product-service ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

As part of this process, the results of the verification - the outcome (boolean) and the detailed information about the failures at the interaction level - are published to the Broker also.

This is one of the Broker's more powerful features. Referred to as Verifications, it allows providers to report back the status of a verification to the broker. You'll get a quick view of the status of each consumer and provider on a nice dashboard. But it is much more important than this!

Can I deploy?

With just a simple use of the pact-broker can-i-deploy tool - the Broker will determine if a consumer or provider is safe to release to the specified environment.

You can run the can-i-deploy checks as follows:

consumer ❯ ./mvnw pact:can-i-deploy -Dpacticipant='ProductCatalogue' -Dlatest=true
[INFO] Scanning for projects...
[INFO] 
[INFO] ------------------< io.pact.workshop:product-service >------------------
[INFO] Building product-service 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven:4.1.17:can-i-deploy (default-cli) @ product-service ---
Computer says yes \o/ 

All required verification results are published and successful
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------


provider ❯ ./mvnw pact:can-i-deploy -Dpacticipant='ProductService' -Dlatest=true
[INFO] Scanning for projects...
[INFO] 
[INFO] ------------------< io.pact.workshop:product-service >------------------
[INFO] Building product-service 1.0-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO] 
[INFO] --- maven:4.1.17:can-i-deploy (default-cli) @ product-service ---
Computer says yes \o/ 

All required verification results are published and successful
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

That's it - you're now a Pact pro. Go build 🔨

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README.md

README.md

Pact Maven + Springboot + JUnit5 workshop

Introduction

Learning objectives

Requirements

Scenario

Start

Start at step 1

Step 1 - Simple Consumer calling Provider

Step 2 - Client Tested but integration fails

Step 3 - Pact to the rescue

Step 4 - Verify the provider

Step 5 - Back to the client we go

Step 6 - Consumer updates contract for missing products

Step 7 - Adding the missing states

Step 8 - Authorization

Step 9 - Implement authorisation on the provider

Step 10 - Request Filters on the Provider

Step 11 - Using a Pact Broker

Running the Pact Broker with docker-compose

Publish contracts from consumer

Verify contracts on Provider

Can I deploy?

Files

README.md

Latest commit

History

README.md

File metadata and controls

Pact Maven + Springboot + JUnit5 workshop

Introduction

Learning objectives

Requirements

Scenario

Start

Start at step 1

Step 1 - Simple Consumer calling Provider

Step 2 - Client Tested but integration fails

Step 3 - Pact to the rescue

Step 4 - Verify the provider

Step 5 - Back to the client we go

Step 6 - Consumer updates contract for missing products

Step 7 - Adding the missing states

Step 8 - Authorization

Step 9 - Implement authorisation on the provider

Step 10 - Request Filters on the Provider

Step 11 - Using a Pact Broker

Running the Pact Broker with docker-compose

Publish contracts from consumer

Verify contracts on Provider

Can I deploy?