Jayanga Dissanayake's Blog: kernel

Showing posts with label kernel. Show all posts

Sunday, March 6, 2016

How to write OSGi tests for C5 compoments

WSO2 C5 Carbon Kernel will be the heart of all the next generation Carbon products. With Kernel version 5.0.0 we introduced PAX OSGi testing.

Now we are trying to ease the life of C5 components developers by providing a utility, which will take care of most of the generic configurations need in OSGi testing. This will enable the C5 component developer to just specify a small number of dependencies and start writing PAX tests for C5 components.

You will have to depend on the following library, except for other PAX dependencies

<dependency>
    <groupId>org.wso2.carbon</groupId>
    <artifactId>carbon-kernel-osgi-test-util</artifactId>
    <version>5.1.0-SNAPSHOT</version>
    <scope>test</scope>
</dependency>

You can find a working sample on the following Git repo
https://github.com/jsdjayanga/c5-sample-osgi-test

Above will load the dependencies you need by default to test Carbon Kernel functionalities. But as a component developer you will have to specify your components jars into the testing environment. This is done via @Configuration annotation in your test class.

Lets assume you work on a bundle org.wso2.carbon.jndi:org.wso2.carbon.jndi, below is how you should specify your dependencies.

    @Configuration
    public Option[] createConfiguration() {
        List<Option> customOptions = new ArrayList<>();
        customOptions.add(mavenBundle().artifactId("org.wso2.carbon.jndi").groupId("org.wso2.carbon.jndi")
                .versionAsInProject());

        CarbonOSGiTestEnvConfigs configs = new CarbonOSGiTestEnvConfigs();
        configs.setCarbonHome("/home/jayanga/WSO2/Training/TestUser/target/carbon-home");
        return CarbonOSGiTestUtils.getAllPaxOptions(configs, customOptions);
    }

Once these are done, your test should ideally work :)

Wednesday, December 23, 2015

The core of the next-generation WSO2 Carbon platform : WSO2 Carbon Kernel 5.0.0

A whole new revamp of the heart of all WSO2 products : WSO2 Carbon Kernel 5.0.0, was released 21 Dec 2015.

Previous versions of the WSO2 Carbon Kernel, (1.x.x to 4.x.x) had a much similar architecture and was tightly coupled with relatively old technologies (axiom, axis2, SOAP, etc.). Which is the same reason, which made us to re-think and re-architecture everything from the ground, and to come up with WSO2 Carbon Kernel 5.0.0.

The new Kernel is armed with the latest technologies and patterns. It will provide the key functionality for server developers on top of the underline OSGi runtime.

Key Features

Transport Management Framework
Logging Framework with Log4j 2.0 as the Backend
Carbon Startup Order Resolver
Dropins Support for OSGi Ready Bundles
Jar to Bundle Conversion Tool
Artifact Deployment Engine
Pluggable Runtime Support

You can download the product from [1], and find more information on [2].

[1] http://product-dist.wso2.com/products/carbon/5.0.0/wso2carbon-kernel-5.0.0.zip
[2] https://docs.wso2.com/display/Carbon500/WSO2+Carbon+Documentation

Thursday, March 26, 2015

WSO2 Carbon : Get notified just after the server start and just before server shutdown

WSO2 Carbon [1] is a 100% open source, integrated and componentized middleware platform which enables you to develop your business and enterprise solutions rapidly. WSO2 Carbon is based on OSGi framework [2]. It inherits molecularity and dynamism from the OSGi.

In this post I am going to show you how to get notified, when the server is starting up and when the server is about to shut down.

In OSGi, bundle start up sequence is random. So you can't rely on the bundle start up sequence.

There are real world scenarios where you have some dependencies amount bundles, hence need to perform some actions before other dependent bundles get deactivated in the server shutdown.

Eg. Let's say you have to send messages to a external system. Your message sending module use your authentication module to authenticate the request and send it to the external system and your message sending module try to send all the buffered messages before the server shutdown.

Bundle unloading sequence in OSGi not happened in a guaranteed sequence. So, what would happen if your authentication bundle get deactivated before your message sending bundle get deactivated. In this case message sending module can't send the messages

To help these type of scenarios WSO2 Carbon framework provide you with a special OSGi service which can be used to detect the server start up and server shutdown

1. How to get notified the server startup

Implement the interface org.wso2.carbon.core.ServerStartupObserver [3], and register it as a service via the bundle context.

When the server is starting you will receive notifications via completingServerStartup() and completedServerStartup()

2. How to get notified the server shutdown

Implement the interface org.wso2.carbon.core.ServerShutdownHandler [4], and register it as a service via the bundle context.

When the server is about to shutdown you will receive the notification via invoke()

eg:

protected void activate(ComponentContext componentContext) {
 try {
     componentContext.getBundleContext().registerService(ServerStartupObserver.class.getName(), new CustomServerStartupObserver(), null) ;
 } catch (Throwable e) {
     log.error("Failed to activate the bundle ", e);
 }
}

[1] http://wso2.com/products/carbon/
[2] http://www.osgi.org/Main/HomePage

[3] https://github.com/wso2/carbon4-kernel/blob/master/core/org.wso2.carbon.core/src/main/java/org/wso2/carbon/core/ServerStartupObserver.java
[4] https://github.com/wso2/carbon4-kernel/blob/master/core/org.wso2.carbon.core/src/main/java/org/wso2/carbon/core/ServerShutdownHandler.java