Presentation slides used duing Apache Stratos Hangout-VI. The Slides explain, how we can design a RESTful API layer for Stratos admin operations. Talks about, #REST #Carbon #Stratos #CXF #OSGi

1. Apache Stratos
Hangout VI
RESTful API for Stratos Controller
Pradeep Fernando
Associate Technical Lead, WSO2 Inc.

2. Outline
● Carbon admin services and how frontend components
interacts with them
● Stratos controller API (existing) and its UI components.
● What it takes to deploy a web-app in Carbon kernel
● Accessing core OSGi services by means of
CarbonContext API
● JAX-RS web-app exposing admin services of Stratos -
big picture
● How Custom web-app frontend/command line tooling
can interact with the deployed REST apis.

3. Carbon Admin Services
- The component which hosts JSP frontends are known as frontend
component
- Backend engine exposes the API via WS
Carbon Backend
Component - OSGi
services
Web-Services Interface
FrontEnd
Component

4. Implementation Class and a
Descriptor File
- There is an implementation class A.K.A. web-
service wrapper class.
- Its defined in a metafile called services.xml

5. Implementation Class
public class RepositoryAdminService {
/**
* Use this method to add a P2 repository to the system.
*
* @param location of the repository to be added
* @param nickName of the repository to be added
* @return true only if the operation is successful
* @throws AxisFault if an exception occurs while adding the repository
*/
public boolean addRepository(String location, String nickName)
/**
* Use this method to update an existing repository
*
* @param prevLocation current location of the repository
* @param prevNickName current name of the repository
* @param updatedLocation new location of the repository
* @param updatedNickName new name of the repository
* @throws AxisFault if an exception occurs while updating the repository
*/
public void updateRepository(String prevLocation, String prevNickName,
String updatedLocation, String updatedNickName)

6. Service Meta File
<service name="RepositoryAdminService" scope="transportsession">
<schema schemaNamespace="http://org.apache.axis2/xsd" elementFormDefaultQualified="true"/>
<transports>
<transport>https</transport>
</transports>
<module ref="ComponentMgtModule"/>
<description>
To administer all the repositories where the installable features are available.
</description>
<parameter name="ServiceClass">org.wso2.carbon.feature.mgt.services.prov.
RepositoryAdminService</parameter>

7. Stratos Controller API
- Tenant Registration
- Cartridge Subscription

8. Deploying a WebApp in Carbon
Kernel
- Kernel packs an embedded Apache Tomcat
- However there is no /webapps directory
- We have to deploy our webapp
programmatically.
- Writing a Deployer would do...

9. Accessing Carbon Server Runtime
from a Co-Hosted WebApp.
- CarbonContext API allows us to access Carbon Runtime
details.
Carbon Server Runtime (OSGi Services)
Co-Hosted
WebApp
:)

10. CarbonContext API...
public String getTenantDomain(boolean resolve)
public int getTenantId(boolean resolve)
public Object getOSGiService(Class clazz)

11. RESTful API for Stratos Backend
Services...
- Using CarbonContext API and co-hosted
external webapp, we retrieve Stratos backend
services.
- We can write a JAX-RS wrapper.
- JAX-RS deployment model is webapp. :)

12. The Big Picture..

13. Implementation Details..
- CXF based JAX-RS webapp
- Wink based webapp.
Personally prefer CXF runtime. But open for
discussion..

14. API Consumers...
- Stratos-CLI can make use of the new API
- Stratos Controller frontend can a webapp
talking to the new API
- The SC frontend can be hosted in a separate
servlet container, or..
- Can be hosted in the same server instance

15. Securely exposing those APIs...
- BasicAuth
- Has to be integrated with the Carbon user-store for
tenant level authentication
- Multitenancy handled as well using CarbonContext
APIs.
- OAuth ?

16. Questions/Suggestions…