Spring Cloud Contract Car Rental

car-rental (consumer)

Sends an HTTP request to fraud detection from a test Gets a Stream message from fraud detection

fraud-detection (producer)

Producer of the HTTP api and messages

Presentation steps

Before

Start Rabbit & Eureka

$ docker-compose up -d
$ spring cloud eureka

Start.spring.io

car-rental

web, stubrunner, stream rabbit, wiremock, Eureka Discovery

and stream-test-support for Contract & Stream

		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-stream-test-support</artifactId>
			<scope>test</scope>
		</dependency>

fraud-detection

web, stream rabbit, verifier, REST Docs, wiremock, Eureka Discovery

and stream-test-support for Contract & Stream

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-stream-test-support</artifactId>
    <scope>test</scope>
</dependency>

and plugin - REMEMBER ABOUT EXTENSIONS

<!-- ADD A PLUGIN -->
<plugin>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-contract-maven-plugin</artifactId>
    <version>${spring-cloud-contract.version}</version>
    <!-- REMEMBER ABOUT THIS LINE -->
    <extensions>true</extensions>
    <configuration>
        <baseClassForTests>com.example.frauddetection.BaseClass</baseClassForTests>
    </configuration>
</plugin>

Code

HTTP

CONSUMER

• Generate consumer from start.spring.io

• Add the missing dependencies

• Start with a test on the consumer side

• Write a not passing test to reach the /fraud endpoint of the producer

• Add the WireMock stub to make the test pass (port 6543)

PRODUCER

• Generate producer from start.spring.io

• Add the missing dependencies

• Write a contract for the /frauds endpoint (the typo is deliberate)

• Configure the plugin with baseClassForTests

• Run ./mvnw clean install - show breaking tests

• Write the controller

• Write missing base class setup

• Rerun the ./mvnw clean install - things pass

• Run the app at port 6544

CONSUMER

• Write a new test that will reach the producer application directly (port 6544)

• The previous test with a stub passes, the new one fails (oops)

• Write a new test with StubRunnerRule com.example:fraud-detection at (port 6545)

• The test fails cause first we’ll shoot at /fraud

• The test passes once we shoot at /frauds

Messaging

CONSUMER

• Enable binding for Sink

• In application.properties

  • set the port to 9876

  • spring.cloud.stream.bindings.input.destination=fraud

  • on the producer side it will be frauds

• Add a Fraud pojo with a name

• Add a FraudListener @Component

  • with a method fraud that has @StreamListener(Sink.class)

  • let it print a message out

  • and store the name

• Let’s write a FraudTests class

  • we want to see if our listener will work fine if we send it our POJO

  • let’s write a test should_store_info_about_fraud

  • make it a SpringBoot test

  • @Autowired FraudListener

  • @Autowired Sink

  • given: a new Fraud("marcin")

  • when: sink.input().send(MessageBuilder.withPayload(fraud).build());

  • then: fraudListener.name == "marcin"

• The test passes - let’s go to the producer

PRODUCER

• EnableBinding(Source.class)

• Set properties

  • spring.cloud.stream.bindings.output.destination=frauds

  • Yup, that’s a typo over there ^^

  • spring.cloud.stream.bindings.output.contentType=application/json

  • server.port=6544

• Let’s write a contract for messaging

  • label trigger_a_fraud

  • input method triggerMethod()

  • output to destination frauds

  • body surname: "Long"

• Create a Fraud pojo in the FraudController

• FraudController will need a @PostMapping("/message") method called message that will use Source to send a message with new Fraud("Long")

• Let’s run ./mvnw clean install and generate tests

  • they will fail cause we have a missing triggerMethod()

• Let’s create the triggerMethod() in the BaseClass

  • Also we need to add the Spring context with @AutoConfigureMessageVerifier

  • @Autowired FraudController

  • call in the triggerMethod() the fraudController.message()

Let’s try to make both apps work! Let’s run them together

curl -X POST http://localhost:6544/message

Nothing happens…​ Even though the tests passed. That’s for 2 reasons

• the destination is wrong. One is sending to frauds the other listening to fraud

• the POJO is wrong. Once expects name the other surname

Time to fix the consumer

CONSUMER

• Let’s use Stub Runner

• @AutoConfigureStubRunner(workOffline = true, ids = "com.example:fraud-detection")

• @Autowired StubTrigger

• stubTrigger.trigger("trigger_a_fraud");

  • the test won’t pass - let’s update the destination

• spring.cloud.stream.bindings.input.destination=frauds

  • let’s run again the tests - still they don’t pass cause the name is wrong

• let’s change Fraud to use surname

  • now if we rerun the tests they pass

Let’s run both apps again, send the CURL - now they should work

REST Docs

PRODUCER

• We need to write a test for the message endpoint

• We’ll write a test called FraudControllerTests

• Use the test slices AutoConfigureMockMvc and @AutoConfigureRestDocs(outputDir = "target/snippets")

  @RunWith(SpringRunner.class)
  @SpringBootTest(classes = FraudDetectionApplication.class)
  @AutoConfigureRestDocs(outputDir = "target/snippets")
  @AutoConfigureMockMvc

• Write a simple test to see if status OK happens when you send a POST to /message/

  @Autowired private MockMvc mockMvc;
  
  	@Test
  	public void should_accept_a_post_message() throws Exception {
  		mockMvc.perform(MockMvcRequestBuilders.post("/message"))
  				.andExpect(MockMvcResultMatchers.status().isOk())
  				.andDo(MockMvcRestDocumentation.document("message"));
  	}

• Time to configure the build to package stuff properly

• We want to disable the default Spring Cloud Contract packaging approach

  • You can do it by setting <spring.cloud.contract.verifier.jar.skip>true</spring.cloud.contract.verifier.jar.skip> property

• Add the src/assembly/stub.xml

  <assembly
          xmlns="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.3"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/plugins/maven-assembly-plugin/assembly/1.1.3 http://maven.apache.org/xsd/assembly-1.1.3.xsd">
      <id>stubs</id>
      <formats>
          <format>jar</format>
      </formats>
      <includeBaseDirectory>false</includeBaseDirectory>
      <fileSets>
          <fileSet>
              <directory>${project.build.directory}/snippets/stubs</directory>
              <outputDirectory>META-INF/${project.groupId}/${project.artifactId}/${project.version}/mappings</outputDirectory>
              <includes>
                  <include>**/*</include>
              </includes>
          </fileSet>
          <fileSet>
              <directory>${project.build.directory}/stubs/META-INF/${project.groupId}/${project.artifactId}/${project.version}/mappings</directory>
              <outputDirectory>META-INF/${project.groupId}/${project.artifactId}/${project.version}/mappings</outputDirectory>
              <includes>
                  <include>**/*</include>
              </includes>
          </fileSet>
          <fileSet>
              <directory>${basedir}/src/test/resources/contracts</directory>
              <outputDirectory>META-INF/${project.groupId}/${project.artifactId}/${project.version}/contracts</outputDirectory>
              <includes>
                  <include>**/*.groovy</include>
              </includes>
          </fileSet>
      </fileSets>
  </assembly>

• Add the assembly plugin setup

  <plugin>
      <groupId>org.apache.maven.plugins</groupId>
      <artifactId>maven-assembly-plugin</artifactId>
      <executions>
          <execution>
              <id>stub</id>
              <phase>prepare-package</phase>
              <goals>
                  <goal>single</goal>
              </goals>
              <inherited>false</inherited>
              <configuration>
                  <attach>true</attach>
                  <descriptor>${basedir}/src/assembly/stub.xml</descriptor>
              </configuration>
          </execution>
      </executions>
  </plugin>

• Run ./mvnw clean install

CONSUMER

• Reuse the previously created setup and just send a post method to /messages. Expect status 200

Discovery

CONSUMER

• Add @EnableDiscoveryClient

• Add @Bean @LoadBalanced for RestTemplate

• Add spring.application.name=car-rental

• In FraudTests we’ll add another test (we need @AutoConfigureStubRunner)

  • @Autowired RestTemplate

  • Use the RestTemplate to call "http://fraud-detection/frauds"

  • The test passes cause SC-Contract redirects the calls via artifact id

Stub Runner Boot

• Clone Stub Runner for Eureka & Rabbit from https://github.com/spring-cloud-samples/github-analytics-stub-runner-boot

• Build it locally

• java -jar target/github-analytics-stub-runner-boot-0.0.1.M1.jar --stubrunner.workoffline=true --stubrunner.ids=com.example:fraud-detection

• Show http://localhost:8083/stubs

• Show http://localhost:8083/triggers

• Show http://localhost:8761 with registered apps

• Run car-rental

• curl -X POST http://localhost:8083/triggers/trigger_a_fraud

• Check that in the logs we see that a message was received

• Write a test that isn’t annotated with @AutoConfigureStubRunner and inject RestTemplate - you can shoot a request to fraud-detection and a stub will respond

  • or write a POST endpoint to /rent that will receive a {"name":"marcin"} and then it will call fraud-detection/frauds to retrieve a list of frauds. If that string contains the name then set status code 406 and text NO. Otherwise 200 and yes and run a curl curl -X POST -d '{"name":"marcin"}' http://localhost:8765

Stub Runner Boot with a NodeJs app

• Install npm

• Install the request module npm install request

• Ensure that Stub Runner Boot is not running

• Go to nodejs folder and execute

  $ node app.js

• You will get sth like this

  ERROR - status [404]

• Next run stub runner boot and show how easy it is to start a stub (this assumes that fraud-detection stubs were installed locally)

  $ git clone https://github.com/spring-cloud-samples/stub-runner-boot
  $ cd stub-runner-boot
  $ ./mvnw clean install -DskipTests
  $ java -jar target/stub-runner-boot-1.1.0.RELEASE.jar --stubrunner.workOffline=true --stubrunner.ids="com.example:fraud-detection:+:9876"

or use Spring Cloud CLI

$ spring cloud stubrunner

• You will get sth like this

  ["marcin","josh"]