Swarm Camel REST Quickstart

Introduction

This quickstart uses WildFly Swarm as Java container and the Apache Camel Integration Framework to expose a RESTfull endpoint registered within the Undertow server. This example uses the REST fluent DSL to define a service which provides one operation

• GET api/say/{id} - Say Hello to the user name

The Camel modules deployed within the WildFly Swarm container are defined within the pom.xml definition file. To expose the JMX MBeans using a HTTP endpoint, we have also packaged to this quickstart project, the jolokia technology which allows to query your MBeans using JSon over HTTP.

To configure jolokia, we must declare a Wildfly fraction which is the composable piece of the platform in order to deploy and customize the module (example: to define the URL path to access the Jolokia JMX resource).

The static resources (index.html file containing the link to the swagger.json doc file) like also the package containing the Camel route are defined within the WAR Archive which is created using ShrinkWrap and deployed after the Container has been started.

The Camel context is created using the CDI Weld Container which is reponsible to scan the classes to discover the @ApplicationScope annotation like also the the @CamelContext annotation which is managed as a cdi extension.

The MainApp class is bootstrapped by the WildFly Swarm container when we launch it.

public static void main(String[] args) throws Exception {
	Container container = new Container();
    container.fraction(new JolokiaFraction("/jmx"));
    container.start();

    WARArchive deployment = ShrinkWrap.create(WARArchive.class);
    deployment.addPackage("io.fabric8.quickstarts.swarm.route");
    deployment.staticContent();

    container.deploy(deployment);

Build

You will need to compile this example first:

mvn install

Run

To run the example type

mvn wildfly-swarm:run

The rest service can be accessed from the following url

curl http://localhost:8080/service/say/{name}

http://localhost:8080/service/say/{name}

For example to say Hello for the name charles

curl http://localhost:8080/service/say/charles

http://localhost:8080/service/say/charles

The rest services provides Swagger API which can be accessed from the following url

curl http://localhost:8080/swagger.json

http://localhost:8080/swagger.json

To stop the example hit ctrl+c

Jolokia & JMX

We have registered the Jolokia fraction in order to access the JMX operations or attributes using the JSon HTTP Servlet Bridge offered by the jolokia project.

Here are some curl request that we can use to grab JVM data

curl -X GET http://localhost:8080/jmx
curl -d "{\"type\":\"read\",\"mbean\":\"java.lang:type=Memory\",\"attribute\":\"HeapMemoryUsage\",\"path\":\"used\"}" http://localhost:8080/jmx/ && echo ""

Running the example in Kubernetes

It is assumed a Kubernetes platform is already running with or without OpenShift. If not, you can find details how to get started.

The example can be built and deployed using a single goal:

mvn fabric8:run

When the example runs in fabric8, you can use the OpenShift client tool to inspect the status

To list all the running pods:

oc get pods

Then find the name of the pod that runs this quickstart, and output the logs from the running pods with:

oc logs <name of pod>

You can also use the fabric8 web console to manage the running pods, and view logs and much more.

Access services using a web browser

You can use any browser to perform a HTTP GET. This allows you to very easily test a few of the RESTful services we defined:

Notice: As it depends on your OpenShift setup, the hostname (route) might vary. Verify with oc get routes which hostname is valid for you.

Use this URL to display response message from the REST service:

http://swarm-camel-rest-default.vagrant.f8/service/say/charles

where vagrant.f8 is your Kubernetes domain and default, the namespace of the project

More details

You can find more details about running this quickstart on the website. This also includes instructions how to change the Docker image user and registry.