alternative to apache felix web console for OSGi - osgi

I am trying to find a CLI alternative to the apache felix web console. I am new to OSGi but am using a project that is built with it. It currently uses the web console to configure managed services. I need to set this up on a remote device though so would prefer a CLI method.
I have read that there is a Config Admin CLI but cannot find any documentation or tutorial on how to use one.

Felix Gogo https://felix.apache.org/documentation/subprojects/apache-felix-gogo.html provides a local console, which may be what you are looking for.
Apache Karaf provides a SSH access to a Gogo console. You might want to investigate how it achieves this. It may be easier to run your project in Karaf than to add SSH support to another project.
Alternatively you could implement a simple tcp server manually, and just interact with config admin directly.

You could use Felix Gogo (apparently latest version is much better and allows to SSH into it) but AFAIK it will not help you much as far as
configuring managed services is concern. While in Gogo you can easily write commands that you execute from the shell, I'm not aware of any existing gogo command that will allow you to change configuration.
Karaf on the other hand uses its own shell (better IMHO). It allows to SSH remotely and it does have commands to add/update configurations. Unfortunately Karaf commands are not compatible with Gogo ones. And Karaf's shell also assumes the runtime is Karaf and thus it's hot directly useful in other environments. However it is possible to install it after some adjustments (I'm currently working on a prototype that integrates it with Liferay for example).

Related

Does Apache Felix FileInstall works for dynamic configuration of an application?

I am trying to develop an application that can be configured by its users. I need the configuration to be done by installing/updating/stopping/uninstalling bundles. All this should be of course done dynamically during the run-time of the application.
I found a nice framework which is Apache Felix FileInstall that provides a directory in which it seems to add a bundle when you add the bundle file in the directory (update, and remove bundles similarly).
But I can see that this method does not work in my case. I need to have the bundles in the directory but to stop or even uninstall them by my application. And I want to install them when it is appropriate. This is how I am expecting the configuration of my application to be done.
Is what I am trying to achieve supported by Apache FileInstall? Am I making any wrong assumptions about this framework? What are other possible ways that would help me if Apache FileInstall is not enough? Thanks.
You don't need FileInstall for this, just use the OSGi APIs. You specifically mentioned installing, updating, stopping and uninstalling; these are supported with the following API calls respectively:
BundleContext.installBundle
Bundle.update
Bundle.stop
Bundle.uninstall
Incidentally these are exactly the same methods that are called by FileInstall to implements its directory-based bundle management.

Branding Apache Felix web console

I am trying to brand a Apache Felix web console, but I am not able to find resource for the same. As per Apache Felix website,
Branding for the Web Console can be provided in two ways: By registering a BrandingPlugin service or by providing a branding properties files. The Web Console uses the branding from the BrandingPlugin service registered with the highest ranking.
But I am not understanding how to register a BrandingPlugin service? What and Jar files should I put? Is there any guidance or tutorial available for the same? If yes, can you guide me in this?
Since I am totaly getting confused with Apache Felix's website, since those documents are not clear on this.
You may find it helpful to do some background reading on OSGi services. OSGi provides a service registry, and most interactions in an OSGi environment are handled by registering and consuming services. It doesn't matter what jar file you put the service in; the only thing that matters is the interface name its registered under.
You can register services in lots of ways; programmatically from a BundleActivator, using Declarative Services (also known as SCR), and using Blueprint are some of the most popular patterns. Which one is easiest for you depends on how you're building your jars and what other OSGi facilities you're using. If you've already got an Activator the programmatic route may be the quickest way to get started; if you're using the Maven bundle plugin you may find SCR annotations easiest.
What you'll need to do is include an implementation of the 'BrandingPlugin' interface in a jar which gets started by your OSGi runtime, and register that implementation as an OSGi service. Once you've done this you should see that the Felix console discovers your BrandingPlugin implementation and uses it.

How and where configure bundles through "apache felix configAdmin"

I try to use the "Apache Felix" implementation of OSGi for my project, I launch the framework from the distributable jar (/bin /felix.jar). I have created simple example bundles to register or consume services in the registry.
I want to use a configuration management service so I installed the bundle "org.apache.felix.configadmin" felix in the framework, and then I do not know how and where to put the configuration file of another bundle, for example I want to install the bundle "org.apache.felix.http.jetty" and then I want to configure this bundle through the configAdmin, so how I rename my config file, and where to put it?
Another question, what is the difference between setting, for example, the property "org.osgi.service.http.port" of the jetty bundle using the framework properties(conf/config.properties) or configure it through the bundle of configuration admin service.
Best regards,
You probably also need the file-installer from felix for it to pick up the config files.
If you want to see a working example of this take a look at Apache Karaf. It's a OSGi Container with lots of nice preconfigured features. The config admin service works out of the box.
Normally you use the felix config admin service together with the felix fileinstall. So fileinstall takes care of the directory to be monitored for config files and hands over to config admin to make it available as configs in OSGi.
For a fully working example take a look at Apache Karaf. There you can see the configs you need for it to work together. You might also consider to simply install your own bundles into karaf as it makes managing the felix framework a lot easier.

Apache Karaf vs. Servicemix

Is anyone using Karaf instead of Servicemix? If so, how did you come to this decision? I'm aware that Servicemix adds a layer of functionality around Karaf, just curious if Karaf is being used on its own and why...
We're using Karaf for a number of our applications. We were already using Camel (JMS and Esper) for integration between several different platforms (a JBoss 4.2 instance, a Tomcat and several Felix instances) and as this was working well there was little justification in migrating this too (which would have been cause to consider ServiceMix).
The only reason we have some Felix nodes, is that they're limited in use (on client desktops), rarely need/get updated and I wanted the smallest footprint for these nodes. For anything OSGi on the serverside we're using Karaf.
Karaf provides all of the features you'd expect and need for a production environment (see the apache-karaf tag's info). We do our development and testing against standard minimal framework (using pax-exam) but deploy to Karaf.
If you don't need an ESB, JCA, BPEL, etc but want a solid, tunable OSGi container, then Karaf on it's own is more than adequate. (And if you found yourself needing a limited subset of ServiceMix's functionality you can always install these in a Karaf instance).
You can also customise the Karaf distribution as part of a maven build - personally I like have the container as part of the application's build, as I can checkout, build and run the entire setup from the command line in minimal time.
Recently there's a clustering subproject of Karaf called Cellar using HazelCast, I not sure if this applies to ServiceMix too.
Karaf's life started as the ServiceMix core. Currently, ServiceMix is really a set of bundles that are deployed into a Karaf container. ServiceMix has a number of very handy bundles which do a lot of cool stuff that karaf doesn't. That said, the two primary reason for using ServiceMix is if you want:
1) an ESB,
2) NMR (a feature that allows you to community between bundles AND instances of Karaf).
This all said, the ServiceMix group is currently planning version 5, which will remove the ESB and NMR features and will be focused on being a management container for Camel. In ESB's a great deal of effort when into creating components that could be described using BPL (Business Process Language). However, the folks that wrote ServiceMix began to focus on the implementation of EIP's (Enterprise Integration Patterns) which largely does the same stuff as BPL, but does it in a more standardized and accepted manner. This work was done under the Camel project.
So, in short. If you are using ServiceMix 4+, you're also using Karaf. If you want a more robust integration environment, the environment of choice today (in the Apache/Felix world at least) is Karaf, Camel, and a few bundles from Servicemix.
Here's a little comparative illustration I made. Going from the simplest case (JVM with OSGi functions provided by Apache Felix at the bottom), to more complete/manageable OSGi functions (Apache Karaf in the middle), to enough functions to implement complete ESB instances (Apache ServiceMix at the top) (note that "an ESB" is not a product but a set of endpoints, routers, databases, ETL functions and whatnot configured together in a particular task-specific way).
Karaf does NOT come with CXF.
Its pure extracted kernel of ServiceMix. However, you can install CXF on Karaf as below.
karaf:root()> feature:repo:add cxf
Once the feature URL is added we can see the "provided" features by using the following command.
karaf:root()> feature:repo:feature:list | grep cxf
To install cxf fire the command below
karaf:root()> feature:install cxf

Auto updating a remote osgi instance (a swing gui)

I am planning to use osgi in a typical client-server (with swing gui) application. Hot deploying bundles to the server is made easy with fileinstall but now I am looking for something similar on the GUI.
The GUI is started with webstart but I want to update bundles without asking the user to close and restart.
I was planning to have a server side bundle which monitors a directory containing bundles, exposes the bundles over http and notifies the clients when something has changed. A client side bundle would listen for the notifications and do the bundle installs/updates using the methods on BundleContext and Bundle.
(Note: I already have an RMI like link between the server and clients which can be used for the notifications)
Is there anything which already does this or similar?
I would at least like to reuse fileinstall for the filesystem watching part but I don't want the GUI bundles started on the server.
P2 is a great provisioning system for OSGi based applications. Eclipse uses it, and there are a lot of uses even for non-OSGi applications. You should definitely have a look at it before you start building you own update system. You can also check Apache Ace.
The Fractal example for the Paremus Service Fabric may be instructive here ( https://docs.paremus.com/display/SF16/Demonstration ). In this example both Server and Client side OSGi bundles may be dynamically installed. RMI is also supported.
Regards
Richard

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