Karaf-Microservices

This is the demo project for the 'Microservices and OSGi' talk held at Apache Con EU 2015 and JavaLand 2015.

It consists of following sub-modules:

• service-api: Module containing the Service API.
• service-impl: Implementation of the API bundle.
• service-configuration: A configuration bundle for easy service configuration in this showcase.
• service-shell-command: Karaf shell commands for easy service testing.
• service-proxy: A cxf jaxrs service proxy on top of the service API.
• service-feature: A Karaf feature module for easy installation of all above bundles.
• service-test: Integration test module testing OSGi Service with Pax-Exam.

Prerequesites

First of all make sure you also have the Karaf-Microservices-Tooling project build. The service-test module does use a specialized pre-configured Karaf instance, Karaf-Service-Runtime.

Building

All of the Microservice samples are can be build with maven.

mvn clean install

while for Dev-Ops development with continous deployment a special deployment goal exists.

karaf-deployer:deploy

With this maven goal you can deploy any module on a Karaf instance (if it's a OSGi bundle) These samples already does have a the usage of this goal preconfigured.

<plugin>
	<groupId>de.nierbeck.javaland.tools</groupId>
	<artifactId>karaf-deployer-maven-plugin</artifactId>
	<configuration>
		<url>http://192.168.59.103:8181/jolokia/</url>
		<jsonInstall>
{
"type":"EXEC",
"mbean":"org.apache.karaf:type=bundle,name=root",
"operation":"install(java.lang.String,boolean)",
"arguments":["mvn:${project.groupId}/${project.artifactId}/${project.version}", true]
}
		</jsonInstall>
		<user>karaf</user>
		<password>karaf</password>
		<skip>false</skip>
	</configuration>
</plugin> 

For easy testing the pre-configured Karaf instance can also be run as Docker image right away from the project. For this call

docker:start

to start the docker instance and

docker:stop

to stop that instance again.

Walkthrough

This is a short walkthrough of this sample.

First make sure you have docker installed and running. Clone the Karaf-Microservices-Tooling from the github repo and do a full build of it. In the Karaf-Docker-Runtime submodule start the Karaf-Docker instance with

mvn docker:start

after this docker container is started it can be used as continuous deployment container for the showcase. The showcase can be build with mvn clean install. To deploy the showcase bundle to the Karaf-Docker instance use:

mvn karaf-deployer:deploy

This will deploy the current bundle in the configured Karaf instance. In case of deploying to the Karaf-Docker instance make sure the ip address is properly configured in the karaf-deployer-maven-plugin section.

complete showcase

For easy testing there is an additional service-configuration bundle, which is enabled by enabling the Configuration profile. The complete showcase including the configuration can be build with

mvn clean install karaf-deployer:deploy -PConfiguration

when ssh'ing into the Karaf instance

ssh [email protected] -p 8101

you'll see all bundles are installed and usable. For example the commands contained in the service-shell-command bundle can be used to test the service.

karaf@root()> microservice:Calculate

proxy REST servlet

The proxy REST servlet is a specialized JAX-RS servlet to proxy calls to any service instance of the CreditCalculator type. Those services are configured via de.nierbeck.microservices.karaf.calculator Service Factory PID. To get a list of all available service instances a GET request to

http://192.168.99.100:8181/cxf/calculator/

lists all available services of type CreditCalculator.

With a GET call to:

http://192.168.99.100:8181/cxf/calculator/find

a sample Calculator JSON object is returned. This JSON can be used for the calculation.

To calculate with a dedicated service instance a POST request to the following URL is required.

http://192.168.99.100:8181/cxf/calculator/JavaBank

For a successful call make sure you have Content-Type set to application/json in the request header. The body to send via POST can be retrieved via the find call.

{
    "credit": {
        "credit": 10000,
        "interest": 2.5,
        "retention": 10
    }
}