Chapter 2. Using Fuse boosters

Open a shell prompt and build the project from the command line, using Maven:

cd PROJECT_DIR
mvn clean package

Open a new shell prompt and start the name service, as follows:

cd name-service
mvn spring-boot:run -DskipTests -Dserver.port=8081

As Spring Boot starts up, you should see some output like the following:

...
2017-12-08 15:44:24.223  INFO 22758 --- [           main] o.a.camel.spring.SpringCamelContext      : Total 1 routes, of which 1 are started
2017-12-08 15:44:24.227  INFO 22758 --- [           main] o.a.camel.spring.SpringCamelContext      : Apache Camel 2.20.0 (CamelContext: camel-1) started in 0.776 seconds
2017-12-08 15:44:24.234  INFO 22758 --- [           main] org.jboss.fuse.boosters.cb.Application   : Started Application in 4.137 seconds (JVM running for 4.744)

Open a new shell prompt and start the greetings service, as follows:

cd greetings-service
mvn spring-boot:run -DskipTests

As Spring Boot starts up, you should see some output like the following:

...
2017-12-08 15:46:58.521  INFO 22887 --- [           main] o.a.c.c.s.CamelHttpTransportServlet      : Initialized CamelHttpTransportServlet[name=CamelServlet, contextPath=]
2017-12-08 15:46:58.524  INFO 22887 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-12-08 15:46:58.536  INFO 22887 --- [           main] org.jboss.fuse.boosters.cb.Application   : Started Application in 6.263 seconds (JVM running for 6.819)

The greetings service exposes a REST endpoint at the URL, http://localhost:8080/camel/greetings.

Go to http://localhost:8080

When you open this page, it invokes the Greeting Service:

This page also provides a link to the Hystrix dashboard, which monitors the state of the circuit breaker.

To demonstrate the circuit breaker functionality provided by Camel Hystrix, kill the backend name service by pressing Ctrl+C while in the window of the shell prompt where the name service is running.

Now that the name service is unavailable, the circuit breaker kicks in to prevent the greetings service from hanging when it is invoked.

Observe the changes in the Hystrix Monitor dashboard and in the Greeting Service output:

Build the project:

cd PROJECT_DIR
mvn clean package

Run the service:

mvn spring-boot:run

Open a web browser to http://localhost:8080. This page invokes a Greeting Service every 5 seconds. The Greetings Service responds by using the booster.nameToGreetvalue from the target/classes/application.properties file.

The Greeting Service prints a greeting to “default” every five seconds:

Modify the booster.nameToGreet value:

Run the service again:

mvn spring-boot:run

In the web browser, return to the http://localhost:8080 page to view the changed value in the Greeting Service’s results window.

Build the project:

cd PROJECT_DIR
mvn clean package

Run the service:

mvn spring-boot:run

To execute the example HTTP GET request, click the camel/greetings/{name} button.

A new web browser window opens with the localhost:8080/camel/greetings/Jacopo URL. The default value of the URL {name} parameter is Jacopo.

The JSON response appears in the browser window:

To change the value of the {name} `parameter, change the URL. For example, to change the name to Thomas, use this URL: `localhost:8080/camel/greetings/Thomas.

The updated JSON response appears in the browser window:

To view the REST API’s Swagger page, click the API Swagger page button.

The API swagger page opens in a browser window.