spring-operator / spring-cloud-contract Goto Github PK

If we wanted to test the application in top left corner to determine whether it can communicate with other services, we could do one of two things:

• Deploy all microservices and perform end-to-end tests.

• Mock other microservices in unit/integration tests.

Both have their advantages but also a lot of disadvantages.

Deploy all microservices and perform end to end tests

Advantages:

• Simulates production.

• Tests real communication between services.

Disadvantages:

• To test one microservice, we have to deploy 6 microservices, a couple of databases, etc.

• The environment where the tests run is locked for a single suite of tests (nobody else would be able to run the tests in the meantime).

• They take a long time to run.

• The feedback comes very late in the process.

• They are extremely hard to debug.

Mock other microservices in unit/integration tests

Advantages:

• They provide very fast feedback.

• They have no infrastructure requirements.

Disadvantages:

• The implementor of the service creates stubs that might have nothing to do with reality.

• You can go to production with passing tests and failing production.

To solve the aforementioned issues, Spring Cloud Contract Verifier with Stub Runner was created. The main idea is to give you very fast feedback, without the need to set up the whole world of microservices. If you work on stubs, then the only applications you need are those that your application directly uses.

Spring Cloud Contract Verifier gives you the certainty that the stubs that you use were created by the service that you’re calling. Also, if you can use them, it means that they were tested against the producer’s side. In short, you can trust those stubs.

This very brief tour walks through using Spring Cloud Contract:

• On the Producer Side

• On the Consumer Side

You can find a somewhat longer tour here.

On the Producer Side

Unresolved directive in verifier_introduction.adoc - include::{introduction_url}/samples/standalone/dsl/http-server/pom.xml[tags=verifier_test_dependencies,indent=0]

<plugin>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-contract-maven-plugin</artifactId>
	<version>${spring-cloud-contract.version}</version>
	<extensions>true</extensions>
</plugin>

On the Consumer Side

Unresolved directive in verifier_introduction.adoc - include::{introduction_url}/samples/standalone/dsl/http-client/pom.xml[tags=stub_runner,indent=0]

@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment=WebEnvironment.NONE)
@AutoConfigureStubRunner(ids = {"com.example:http-server-dsl:+:stubs:6565"},
		stubsMode = StubRunnerProperties.StubsMode.LOCAL)
public class LoanApplicationServiceTests {

This brief tour walks through using Spring Cloud Contract:

• On the Producer Side

• On the Consumer Side

You can find an even more brief tour here.

On the Producer Side

package contracts

org.springframework.cloud.contract.spec.Contract.make {
	request {
		method 'PUT'
		url '/fraudcheck'
		body([
			   "client.id": $(regex('[0-9]{10}')),
			   loanAmount: 99999
		])
		headers {
			contentType('application/json')
		}
	}
	response {
		status OK()
		body([
			   fraudCheckStatus: "FRAUD",
			   "rejection.reason": "Amount too high"
		])
		headers {
			contentType('application/json')
		}
	}
}

request:
  method: PUT
  url: /fraudcheck
  body:
    "client.id": 1234567890
    loanAmount: 99999
  headers:
    Content-Type: application/json
  matchers:
    body:
      - path: $.['client.id']
        type: by_regex
        value: "[0-9]{10}"
response:
  status: 200
  body:
    fraudCheckStatus: "FRAUD"
    "rejection.reason": "Amount too high"
  headers:
    Content-Type: application/json;charset=UTF-8

Unresolved directive in verifier_introduction.adoc - include::{verifier_core_path}/src/test/groovy/org/springframework/cloud/contract/verifier/builder/MessagingMethodBodyBuilderSpec.groovy[tags=trigger_no_output_dsl]

Unresolved directive in verifier_introduction.adoc - include::{verifier_core_path}/src/test/resources/yml/contract_message_scenario3.yml[indent=0]

Unresolved directive in verifier_introduction.adoc - include::{introduction_url}/samples/standalone/dsl/http-server/pom.xml[tags=verifier_test_dependencies,indent=0]

<plugin>
	<groupId>org.springframework.cloud</groupId>
	<artifactId>spring-cloud-contract-maven-plugin</artifactId>
	<version>${spring-cloud-contract.version}</version>
	<extensions>true</extensions>
</plugin>

@Test
public void validate_shouldMarkClientAsFraud() throws Exception {
    // given:
        MockMvcRequestSpecification request = given()
                .header("Content-Type", "application/vnd.fraud.v1+json")
                .body("{\"client.id\":\"1234567890\",\"loanAmount\":99999}");

    // when:
        ResponseOptions response = given().spec(request)
                .put("/fraudcheck");

    // then:
        assertThat(response.statusCode()).isEqualTo(200);
        assertThat(response.header("Content-Type")).matches("application/vnd.fraud.v1.json.*");
    // and:
        DocumentContext parsedJson = JsonPath.parse(response.getBody().asString());
        assertThatJson(parsedJson).field("['fraudCheckStatus']").matches("[A-Z]{5}");
        assertThatJson(parsedJson).field("['rejection.reason']").isEqualTo("Amount too high");
}

[source,java,indent=0]

@Test
	public void validate_shouldRejectABeerIfTooYoung() throws Exception {
		// given:
			WebTestClientRequestSpecification request = given()
					.header("Content-Type", "application/json")
					.body("{\"age\":10}");

		// when:
			WebTestClientResponse response = given().spec(request)
					.post("/check");

		// then:
			assertThat(response.statusCode()).isEqualTo(200);
			assertThat(response.header("Content-Type")).matches("application/json.*");
		// and:
			DocumentContext parsedJson = JsonPath.parse(response.getBody().asString());
			assertThatJson(parsedJson).field("['status']").isEqualTo("NOT_OK");
	}

[source,groovy,indent=0]

given:
	 ContractVerifierMessage inputMessage = contractVerifierMessaging.create(
		\'\'\'{"bookName":"foo"}\'\'\',
		['sample': 'header']
	)

when:
	 contractVerifierMessaging.send(inputMessage, 'jms:delete')

then:
	 noExceptionThrown()
	 bookWasDeleted()

[INFO] --- spring-cloud-contract-maven-plugin:1.0.0.BUILD-SNAPSHOT:generateStubs (default-generateStubs) @ http-server ---
[INFO] Building jar: /some/path/http-server/target/http-server-0.0.1-SNAPSHOT-stubs.jar
[INFO]
[INFO] --- maven-jar-plugin:2.6:jar (default-jar) @ http-server ---
[INFO] Building jar: /some/path/http-server/target/http-server-0.0.1-SNAPSHOT.jar
[INFO]
[INFO] --- spring-boot-maven-plugin:1.5.5.BUILD-SNAPSHOT:repackage (default) @ http-server ---
[INFO]
[INFO] --- maven-install-plugin:2.5.2:install (default-install) @ http-server ---
[INFO] Installing /some/path/http-server/target/http-server-0.0.1-SNAPSHOT.jar to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT.jar
[INFO] Installing /some/path/http-server/pom.xml to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT.pom
[INFO] Installing /some/path/http-server/target/http-server-0.0.1-SNAPSHOT-stubs.jar to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar

On the Consumer Side

Unresolved directive in verifier_introduction.adoc - include::{introduction_url}/samples/standalone/dsl/http-client/pom.xml[tags=stub_runner,indent=0]

@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment=WebEnvironment.NONE)
@AutoConfigureStubRunner(ids = {"com.example:http-server-dsl:+:stubs:6565"},
		stubsMode = StubRunnerProperties.StubsMode.LOCAL)
public class LoanApplicationServiceTests {

2016-07-19 14:22:25.403  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Desired version is + - will try to resolve the latest version
2016-07-19 14:22:25.438  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Resolved version is 0.0.1-SNAPSHOT
2016-07-19 14:22:25.439  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Resolving artifact com.example:http-server:jar:stubs:0.0.1-SNAPSHOT using remote repositories []
2016-07-19 14:22:25.451  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Resolved artifact com.example:http-server:jar:stubs:0.0.1-SNAPSHOT to /path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar
2016-07-19 14:22:25.465  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Unpacking stub from JAR [URI: file:/path/to/your/.m2/repository/com/example/http-server/0.0.1-SNAPSHOT/http-server-0.0.1-SNAPSHOT-stubs.jar]
2016-07-19 14:22:25.475  INFO 41050 --- [           main] o.s.c.c.stubrunner.AetherStubDownloader  : Unpacked file to [/var/folders/0p/xwq47sq106x1_g3dtv6qfm940000gq/T/contracts100276532569594265]
2016-07-19 14:22:27.737  INFO 41050 --- [           main] o.s.c.c.stubrunner.StubRunnerExecutor    : All stubs are now running RunningStubs [namesAndPorts={com.example:http-server:0.0.1-SNAPSHOT:stubs=8080}]

As consumers of services, we need to define what exactly we want to achieve. We need to formulate our expectations. That is why we write contracts.

Assume that you want to send a request containing the ID of a client company and the amount it wants to borrow from us. You also want to send it to the /fraudcheck url via the PUT method.

Spring Cloud Contract generates stubs, which you can use during client-side testing. You get a running WireMock instance/Messaging route that simulates the service. You would like to feed that instance with a proper stub definition.

At some point in time, you need to send a request to the Fraud Detection service.

Annotate your test class with @AutoConfigureStubRunner. In the annotation provide the group id and artifact id for the Stub Runner to download stubs of your collaborators.

After that, during the tests, Spring Cloud Contract automatically finds the stubs (simulating the real service) in the Maven repository and exposes them on a configured (or random) port.

Since you are developing your stub, you need to be sure that it actually resembles your concrete implementation. You cannot have a situation where your stub acts in one way and your application behaves in a different way, especially in production.

To ensure that your application behaves the way you define in your stub, tests are generated from the stub you provide.

The autogenerated test looks, more or less, like this:

If using the SNAPSHOT / Milestone / Release Candidate versions please add the following section to your build:

As a developer of the Loan Issuance service (a consumer of the Fraud Detection server), you might do the following steps:

1. Start doing TDD by writing a test for your feature.

2. Write the missing implementation.

3. Clone the Fraud Detection service repository locally.

4. Define the contract locally in the repo of Fraud Detection service.

5. Add the Spring Cloud Contract Verifier plugin.

6. Run the integration tests.

7. File a pull request.

8. Create an initial implementation.

9. Take over the pull request.

10. Write the missing implementation.

11. Deploy your app.

12. Work online.

Start doing TDD by writing a test for your feature.

Assume that you have written a test of your new feature. If a loan application for a big amount is received, the system should reject that loan application with some description.

Write the missing implementation.

At some point in time, you need to send a request to the Fraud Detection service. Assume that you need to send the request containing the ID of the client and the amount the client wants to borrow. You want to send it to the /fraudcheck url via the PUT method.

For simplicity, the port of the Fraud Detection service is set to 8080, and the application runs on 8090.

If you start the test at this point, it breaks, because no service currently runs on port 8080.

Clone the Fraud Detection service repository locally.

You can start by playing around with the server side contract. To do so, you must first clone it.

Define the contract locally in the repo of Fraud Detection service.

As a consumer, you need to define what exactly you want to achieve. You need to formulate your expectations. To do so, write the following contract:

The YML contract is quite straight-forward. However when you take a look at the Contract written using a statically typed Groovy DSL - you might wonder what the value(client(…​), server(…​)) parts are. By using this notation, Spring Cloud Contract lets you define parts of a JSON block, a URL, etc., which are dynamic. In case of an identifier or a timestamp, you need not hardcode a value. You want to allow some different ranges of values. To enable ranges of values, you can set regular expressions matching those values for the consumer side. You can provide the body by means of either a map notation or String with interpolations. Consult the [contract-dsl] section for more information. We highly recommend using the map notation!

The previously shown contract is an agreement between two sides that:

• if an HTTP request is sent with all of

  • a PUT method on the /fraudcheck endpoint,

  • a JSON body with a client.id that matches the regular expression [0-9]{10} and loanAmount equal to 99999,

  • and a Content-Type header with a value of application/vnd.fraud.v1+json,

• then an HTTP response is sent to the consumer that

  • has status 200,

  • contains a JSON body with the fraudCheckStatus field containing a value FRAUD and the rejectionReason field having value Amount too high,

  • and a Content-Type header with a value of application/vnd.fraud.v1+json.

Once you are ready to check the API in practice in the integration tests, you need to install the stubs locally.

Add the Spring Cloud Contract Verifier plugin.

We can add either a Maven or a Gradle plugin. In this example, you see how to add Maven. First, add the Spring Cloud Contract BOM.

Next, add the Spring Cloud Contract Verifier Maven plugin

Since the plugin was added, you get the Spring Cloud Contract Verifier features which, from the provided contracts:

• generate and run tests

• produce and install stubs

You do not want to generate tests since you, as the consumer, want only to play with the stubs. You need to skip the test generation and execution. When you execute:

In the logs, you see something like this:

The following line is extremely important:

It confirms that the stubs of the http-server have been installed in the local repository.

Run the integration tests.

In order to profit from the Spring Cloud Contract Stub Runner functionality of automatic stub downloading, you must do the following in your consumer side project (Loan Application service):

Add the Spring Cloud Contract BOM:

Add the dependency to Spring Cloud Contract Stub Runner:

Annotate your test class with @AutoConfigureStubRunner. In the annotation, provide the group-id and artifact-id for the Stub Runner to download the stubs of your collaborators. (Optional step) Because you’re playing with the collaborators offline, you can also provide the offline work switch (StubRunnerProperties.StubsMode.LOCAL).

Now, when you run your tests, you see something like this:

This output means that Stub Runner has found your stubs and started a server for your app with group id com.example, artifact id http-server with version 0.0.1-SNAPSHOT of the stubs and with stubs classifier on port 8080.

File a pull request.

What you have done until now is an iterative process. You can play around with the contract, install it locally, and work on the consumer side until the contract works as you wish.

Once you are satisfied with the results and the test passes, publish a pull request to the server side. Currently, the consumer side work is done.

As a developer of the Fraud Detection server (a server to the Loan Issuance service):

Create an initial implementation.

As a reminder, you can see the initial implementation here:

Take over the pull request.

You must add the dependencies needed by the autogenerated tests:

In the configuration of the Maven plugin, pass the packageWithBaseClasses property

All the generated tests extend that class. Over there, you can set up your Spring Context or whatever is necessary. In this case, use Rest Assured MVC to start the server side FraudDetectionController.

Now, if you run the ./mvnw clean install, you get something like this:

This error occurs because you have a new contract from which a test was generated and it failed since you have not implemented the feature. The auto-generated test would look like this:

If you used the Groovy DSL, you can see, all the producer() parts of the Contract that were present in the value(consumer(…​), producer(…​)) blocks got injected into the test. In case of using YAML, the same applied for the matchers sections of the response.

Note that, on the producer side, you are also doing TDD. The expectations are expressed in the form of a test. This test sends a request to our own application with the URL, headers, and body defined in the contract. It also is expecting precisely defined values in the response. In other words, you have the red part of red, green, and refactor. It is time to convert the red into the green.

Write the missing implementation.

Because you know the expected input and expected output, you can write the missing implementation:

When you execute ./mvnw clean install again, the tests pass. Since the Spring Cloud Contract Verifier plugin adds the tests to the generated-test-sources, you can actually run those tests from your IDE.

Deploy your app.

Once you finish your work, you can deploy your change. First, merge the branch:

Your CI might run something like ./mvnw clean deploy, which would publish both the application and the stub artifacts.

As a developer of the Loan Issuance service (a consumer of the Fraud Detection server):

Merge branch to master.

Work online.

Now you can disable the offline work for Spring Cloud Contract Stub Runner and indicate where the repository with your stubs is located. At this moment the stubs of the server side are automatically downloaded from Nexus/Artifactory. You can set the value of stubsMode to REMOTE. The following code shows an example of achieving the same thing by changing the properties.

That’s it!

You can check out the video from the Warsaw JUG about Spring Cloud Contract:

• Slides from Marcin Grzejszczak’s talk about Accurest

• Accurest related articles from Marcin Grzejszczak’s blog

• Spring Cloud Contract related articles from Marcin Grzejszczak’s blog

• Groovy docs regarding JSON

@RunWith(SpringRunner.class)
@SpringBootTest
@AutoConfigureWireMock(stubs="classpath:/stubs")
public class WiremockImportApplicationTests {

	@Autowired
	private Service service;

	@Test
	public void contextLoads() throws Exception {
		assertThat(this.service.go()).isEqualTo("Hello World!");
	}

}

@RunWith(SpringRunner.class)
@SpringBootTest
@AutoConfigureRestDocs(outputDir = "target/snippets")
@AutoConfigureMockMvc
public class ApplicationTests {

	@Autowired
	private MockMvc mockMvc;

	@Test
	public void contextLoads() throws Exception {
		mockMvc.perform(post("/resource")
                .content("{\"id\":\"123456\",\"message\":\"Hello World\"}"))
				.andExpect(status().isOk())
				.andDo(verify().jsonPath("$.id")
                        .stub("resource"));
	}
}

└── src
    ├── checkstyle
    │   └── checkstyle-suppressions.xml (3)
    └── main
        └── resources
            ├── checkstyle-header.txt (2)
            └── checkstyle.xml (1)

Checkstyle rules are disabled by default. To add checkstyle to your project just define the following properties and plugins.

1. Fails the build upon Checkstyle errors

2. Fails the build upon Checkstyle violations

3. Checkstyle analyzes also the test sources

4. Add the Spring Java Format plugin that will reformat your code to pass most of the Checkstyle formatting rules

5. Add checkstyle plugin to your build and reporting phases

If you need to suppress some rules (e.g. line length needs to be longer), then it’s enough for you to define a file under ${project.root}/src/checkstyle/checkstyle-suppressions.xml with your suppressions. Example:

It’s advisable to copy the ${spring-cloud-build.rootFolder}/.editorconfig and ${spring-cloud-build.rootFolder}/.springformat to your project. That way, some default formatting rules will be applied. You can do so by running this script:

In order to setup Intellij you should import our coding conventions, inspection profiles and set up the checkstyle plugin.

1. Default Checkstyle rules

2. File header setup

3. Default suppression rules

4. Project defaults for Intellij that apply most of Checkstyle rules

5. Project style conventions for Intellij that apply most of Checkstyle rules

Go to File → Settings → Editor → Code style. There click on the icon next to the Scheme section. There, click on the Import Scheme value and pick the Intellij IDEA code style XML option. Import the spring-cloud-build-tools/src/main/resources/intellij/Intellij_Spring_Boot_Java_Conventions.xml file.

Go to File → Settings → Editor → Inspections. There click on the icon next to the Profile section. There, click on the Import Profile and import the spring-cloud-build-tools/src/main/resources/intellij/Intellij_Project_Defaults.xml file.

To have Intellij work with Checkstyle, you have to install the Checkstyle plugin. It’s advisable to also install the Assertions2Assertj to automatically convert the JUnit assertions

Go to File → Settings → Other settings → Checkstyle. There click on the + icon in the Configuration file section. There, you’ll have to define where the checkstyle rules should be picked from. In the image above, we’ve picked the rules from the cloned Spring Cloud Build repository. However, you can point to the Spring Cloud Build’s GitHub repository (e.g. for the checkstyle.xml : https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/spring-cloud-build-tools/src/main/resources/checkstyle.xml). We need to provide the following variables:

• checkstyle.header.file - please point it to the Spring Cloud Build’s, spring-cloud-build-tools/src/main/resources/checkstyle/checkstyle-header.txt file either in your cloned repo or via the https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/spring-cloud-build-tools/src/main/resources/checkstyle-header.txt URL.

• checkstyle.suppressions.file - default suppressions. Please point it to the Spring Cloud Build’s, spring-cloud-build-tools/src/checkstyle/checkstyle-suppressions.xml file either in your cloned repo or via the https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/spring-cloud-build-tools/src/checkstyle/checkstyle-suppressions.xml URL.

• checkstyle.additional.suppressions.file - this variable corresponds to suppressions in your local project. E.g. you’re working on spring-cloud-contract. Then point to the project-root/src/checkstyle/checkstyle-suppressions.xml folder. Example for spring-cloud-contract would be: /home/username/spring-cloud-contract/src/checkstyle/checkstyle-suppressions.xml.