#osgi

Problem Statement: How can I invoke the Sling servlet from the OSGI service or from Sling Model? Introduction: We are aware of invoking a service by using @Reference @OSGiService if are referring to any other sling model inside the Sling servlet you can also use adaptTo({class-name}.class) to invoke a sling model within a servlet. But is there any way we can invoke servlet from the Sling…

Если загуглить словосочетание из шапки поста, то на момент написания этого поста, первым определением будет статья на medium, которая гласит: “Apache Karaf — это небольшой OSGi контейнер, в котором могут быть запущены OSGi бандлы и веб приложения.“

Если перейти сразу к делу, то идём на официальный сайт ( https://karaf.apache.org/download.html ) и выкачиваем последнюю версию, на момент написания статьи, версия “Karaf Runtime 4.2.9″.

Consume OSGI Service in Liferay Portlet

We can easily Consume OSGI Service in Liferay Portlet. Before reading this article please read my previous article. This article is an extension of the previous article. In this article we will create a Sample Portlet and consume the OSGI Service which is explained in the previous article.

Read my previous article

http://proliferay.com/writing-your-first-osgi-service-in-liferay-7/

For…

Writing your first OSGI Service in Liferay 7

In this article we will try to understand about OSI Service and its usage. In Liferay 7, OSGI plays a vital role. So its very important to understand the basics of OSGI Service. In this article we will create a basic OSGI service and in the next article we will create a portlet to consume this service.

Whats OSGI Service???

1.An OSGI Service is simply a instance of Java Object registered in…

Liferay 7-OSGI Module – MVC Portlet by Maven

Using Maven we can easily create OSGI module in Liferay 7. Liferay has already published many Maven Archetypes for creating OSGI based application. In this article we will show how to create a basic MVC Portlet using Maven as build tool. The archetype is capable of generating necessary source code compliance with OSGI specification. The portlet will be packaged as OSGI module which is nothing…

Marcel Offermans

This was a shorter presentation (hour), which was a nice change.

Good set of demos with no gremlins striking.

Still have no definitive definition of MS.  I think the pragmatists think of them as just yet-another service that is well designed and has a process boundary.

But even the process boundary stuff does not look hard-n-fast, since this presentation talk about the reality of small IoT environments that will normally require all services to be co-located in a single device runtime.

Modularity

Nothing new here, but Modularity mentioned as being important, not only in the context of MS, but good design.

Org Structure

This point was worth the talk, and i think is a great usecase for MS.

Conways Law:

"Any organization that designs a system will inevitably produce a design whose structure is a copy of the organization's communication structure."

Wow, that’s cool.  Particularly since the law stated generally, not just for software systems.  

Given this reality, then it would be worth considering having micorservice design and boundaries mirror the development org structure?  

Or if that is completely unreasonable, then maybe the org structure should be changed to reflect a better software design structure?-)

Sure enough if you google “conways law microservices” there are many articles floating around on this topic.

Case Study: Entertainment System

A sample product that ran through the rest of the talk was an Entertainment system.

It modeled a Dashboard that could have an arbitrary collection of Applications plugged into it.

OSGI

Here is where things turned not as cool for me, but once i embraced it, then i was glad to take the detour.

It turns out that everything following was implemented in the context of OSGI.

Not that i’m not a fan of OSGI, but i felt it was not fair that the title of the talk not include OSGI since it was such a heavy part of the talk.

But once i got over that, it became an opportunity to see some cool things from the world of OSGI.

If it was not for Jigswaw creating OSGI uncertainty, i would persue it more deeply. 

OSGI has some flaw that only the VM can solve (Jigsaw).  But it is battle tested and proven for almost a decade and has quite a mature ecosystem of tools.

Some of the tools that were used:

Eclipse, Gradle

Apache Felix (very large OSGI framework)

Amdatu  (OS project with an impressive array of tools for modular OSGI development)

BND for Eclipse (popular utility tool for OSGI dev).

Apache ACE (an impressive looking framework to manage OSGI artifacts and automated deployments). 

The demo included an OSGI component that provides very cool shell for an app.  He used the shell to control the components.

He used JaxRS to implement REST API endpoints.  But did not use REST for intra-MS communication.

He used OSGI Remote Services for MS communication (an OSGI remoting extension).

So the OSGI container hosted the OSGI MS’s.

He used an OSGI registry to dynamically wire MS’s together.

For example: 

The Dashboard is listening for Application Registry changes, then plug and play depending on events.

He demonstrated Apache ACE to automate the deployment of OSGI modules to target machines.  It also acts as an artifact repository (similar to Maven), with versioned components.

IoT

The IoT discussion was just jammed in the end of the talk.

IoTIPv6 for identity.

talk about device Sessors.

Communication: Bluetooth, ZigBee, WiFi.

Need to deal with a not-always-on.

In many cases the device must be autonomous.

deployment

All MS on the same device.

Resource constrained.

Updates done over limited connections.

He did make the point that IoT MS’s are often all co-located on the same device, but there is still value in having strong MS-like module boundaries (which OSGI provides).