How to create Restful service and deploy it OSGi container?

Question

My goal is to create a Restful service Maven project with Eclipse. Then package it as a bundle and deploy it to Fuse ESB karaf OSGi container. So far what I know is how to use the JAX-RS API annotations, @Path @GET:

package com.restfultest;

import javax.ws.rs.GET;
import javax.ws.rs.Path;

@Path("/example")
public class ExampleService {

@GET
public String sayHello() {
    return "Hello Restful service";
 }
}

My question is that: 1. what maven archetype should I use? maven-archetype-webapp or quickstart?

2.How to implement Activator? Like this?

public class Activator implements BundleActivator {

private ServiceRegistration<?> registration;

public void start(BundleContext context) throws Exception {
    // TODO Auto-generated method stub
    ExampleService exampleService = new ExampleService();
    registration = context.registerService( ExampleService.class.getName(), exampleService, null );
}

public void stop(BundleContext context) throws Exception {
    // TODO Auto-generated method stub
    registration.unregister();
}

}

3. How to register and publish the service (like how to configure the Endpoint address and port)?

I am new to osgi. Does anyone can provide me some resources or a detailed tutorial?

Answer 1

1. You can use Maven bundle plugin
2. and 3. Apache CXF DOSGi helps you to publish OSGi services as WS/REST.

Answer 2

Here is my 5 cent:

1. What Maven archetype should you use?

• I used the OSGI HTTP Service (Quick Start), check this sample, I considered it was more natural.

2. How to implement Activator?

• Go ahead and use the Activator of the sample, it worked for me.
• If you use it, you also will need to implement the the Application and the Rest Service

3. How to register and publish the service?

• I recommend you to download the latest jersey-ALL-bundle and install it on your OSGI.

• And then, in my particular case, I used the Maven Bundle Plugin to handle the imports on Runtime and packing, so, my pom.xml looks something like this (Please notice the dependencies):

  ...
  <packaging>bundle</packaging>
  <build>
      <plugins>
          <!--+
              + OSGi Bundle-Manifiest Generator.
              + -->
          <plugin>
              <groupId>org.apache.felix</groupId>
              <artifactId>maven-bundle-plugin</artifactId>
              <version>2.3.7</version>
              <extensions>true</extensions>
              <configuration>
                  <instructions>
                      <Import-Package>javax.servlet.*;version="[2.4,4.0)",*</Import-Package>
                      <Bundle-Activator>com.sample.api.Activator</Bundle-Activator>
                      <Implementation-Title>jersey-osgi-http-service-bundle</Implementation-Title>
                      <Implementation-Version>${project.version}</Implementation-Version>
                  </instructions>
                  <unpackBundle>true</unpackBundle>
              </configuration>
          </plugin>
      </plugins>
  </build>
  
  <dependencies>
      <!--+======================+-->
      <!--+ REST Dependencies    +-->
      <!--+======================+-->
      <dependency>
          <groupId>org.glassfish.jersey.containers</groupId>
          <artifactId>jersey-container-servlet-core</artifactId>
          <version>2.22.1</version>
      </dependency>
      <dependency>
          <groupId>org.apache.felix</groupId>
          <artifactId>org.apache.felix.http.bundle</artifactId>
          <version>2.2.0</version>
      </dependency>
      <!--+=========================================+-->
      <!--+ Apache Felix Framework (OSGi framework) +-->
      <!--+=========================================+-->
      <dependency>
          <groupId>org.apache.felix</groupId>
          <artifactId>org.apache.felix.framework</artifactId>
          <version>4.6.0</version>
      </dependency>
  </dependencies>
  

• In my specific case I have also the WebConsole installed, then my bundles look like this:

   0|Active     |    0|System Bundle (4.6.0)
   1|Active     |    1|Apache Felix Bundle Repository (2.0.2)
   2|Active     |    1|Apache Felix Gogo Command (0.14.0)
   3|Active     |    1|Apache Felix Gogo Runtime (0.12.1)
   4|Active     |    1|Apache Felix Gogo Shell (0.10.0)
   5|Active     |    1|com.sample-api (1.3.0.SNAPSHOT)
   6|Active     |    1|jersey-all (2.22.1)
   7|Active     |    1|Apache Felix Log Service (1.0.0)
   8|Active     |    1|Apache Felix Configuration Admin Service (1.2.4)
   9|Active     |    1|Apache Felix Shell Service (1.4.2)    
  10|Active     |    1|Apache Felix Http Bundle (2.0.4)    
  11|Active     |    1|HTTP Service (1.0.0)    
  12|Active     |    1|Apache Felix Web Management Console (3.1.2)
  

• For Rest it's important to have the bundles 6, 10 and 11.

• And the port is configurable in the "config.properties" of the OSGI (I used Felix) just by doing this:

  org.osgi.service.http.port=28370
  

• Then, to reach the service just use the following path:

  http://localhost:28370/jersey-http-service/status