In this tutorial, we check out the basic functionality of the Stub Runner Boot application. Stub Runner Boot is a standalone JAR that you can run to download the latest stubs and have them started in fake HTTP servers.

We demonstrate only the HTTP side of the Stub Runner Boot. However, the tool is far more powerful. There are also options to:

  • End messages defined in contracts to real queues.

  • Register the stubs in a real discovery service.

Adding the Stout Endpoint

Let’s open the producer_advanced project and define a new endpoint called /stout. We can start with a contract. Let’s call it shouldReturnStout.groovy:

Contract.make {
	request {
		method 'GET'
		url '/stout'
	}
	response {
		status 200
		body("STOUT")
		headers {
			contentType(textPlain())
		}
	}
}

Now, let’s create the StoutController, as follows:

@RestController
public class StoutController {

	@GetMapping("/stout")
	String stout() {
		return "STOUT";
	}
}

In BeerRestBase, we need to add another controller to RestAssured, as follows:

RestAssuredMockMvc.standaloneSetup(..., new StoutController(), ...);

Let’s install the stubs locally, as shown for both Maven and Gradle in the following code snippet:

Maven
./mvnw clean install

+

Gradle
./gradlew clean build publishToMavenLocal
  • Great! Now let’s move to a terminal.

Running Stub Runner Boot

Stub Runner Boot is a fat JAR that can be configured via a single annotation. We will use an already packaged JAR, so you don’t need to follow these steps. You can: * add the stub runner starter to the classpath, as follows: include::snippets/consumer_stub_runner_dep.adoc[]. * annotate your main class with @EnableStubRunnerServer.

The following class shows an example of such a class:

@SpringBootApplication
@EnableStubRunnerServer
public class StubRunnerBoot {

	public static void main(String[] args) {
		SpringApplication.run(StubRunnerBoot.class, args);
	}
}

We can download a prepackaged JAR, as follows:

URL="https://dl.bintray.com/marcingrzejszczak/maven/stub-runner-boot-1.1.0.RELEASE.jar"
VERSION="1.1.0.RELEASE"
JAR_NAME="stub-runner-boot-${VERSION}"
JAR_LOCATION="target/${JAR_NAME}.jar"

mkdir -p target
curl -L "${URL}" -o "${JAR_LOCATION}"

Now let’s run the Stub Runner Boot application. We want to work in offline mode, and we want to download the JAR containing the latest stubs of com.example:beer-api-producer-advanced and start it on a random port. The following script shows how to do all that:

echo "Running stub runner"
nohup java -jar "${JAR_LOCATION}" --stubrunner.stubs-mode="local" --stubrunner.ids="com.example:beer-api-producer-advanced" 2>&1 &
Tip
You can run the Stub Runner Boot without nohup, but then you have to start a new terminal window for the rest of this tutorial. If you check the nohup.log output file, you can see that the app has started and it has downloaded the stubs locally. It has started on port 8083. Now let’s curl a request to the /stubs and try to retrieve the port on which our stub has started. Once we have it, we can curl the /stout endpoint.
echo "Show all running stubs"
curl -s localhost:8083/stubs
echo "Get the port of stub"
STUB_PORT=`curl -s localhost:8083/stubs/beer-api-producer-advanced`
curl "localhost:${STUB_PORT}/stout"

We should get a STOUT string on the terminal.

Tip
There are also /trigger endpoints available if you want to trigger some messaging labels. You can read more about them in the docs. For the Spring Cloud Pipelines project, we have a Stub Runner Boot application that uses a real instance of RabbitMQ for messaging and registers stubs in Eureka. You can check the code here.
Important
Remember to kill the Stub Runner application. You can do so with the following command: pkill -f stub-runner-boot

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