I am new to the OSGI world and could use some advice from the experts out there. My aim is to deploy a few servlets along with REST resources into a standard Karaf installation. I am planning to use Grizzly (w/Jersey) as the http container.
I am trying to figure out a way to create an eclipse project, in which I can compile my custom code, and deploy this code along with all dependencies such as Grizzly, Jersey, OSGI frameworks & bundles as a single archive into Karaf.
The end goal is to have a single deployable entity which includes all my code and the dependencies without needing to manually install dependencies in Karaf.
Is this possible or am I looking at it the wrong way? I have been reading up on OBR, features and KAR but not able to put the whole picture together as yet. What would be the best practice wrt achieving this objective?
Thanks!
To give you the general idea regarding embedding and launching a complete OSGi application, I suggest you check out chapter 13 on this book. It explains it using Equinox implementation but I hope the overall approach should look similar. If you follow through you will see that you can put all your bundles in a folder where the system will iterate through and install them.
Related
I am stuck with a problem I can't solve for weaks now.
I have to create a modular JavaFX application, where each component defines a "domain unit" (with models+views+controllers). Each component can be loaded into a "shell application" (as a content of a tab view or multiple tab views) and the modules can depend on another module(s) (their content in tabs won't appear if their dependency is not loaded).
That's why I was planning to create an OSGi based JavaFX application and build it with Gradle as a multiproject.
I've already tried dozens of tutorials with no success and I experienced, that most of these tutorials:
are outdated, not reproducible (e.g. elcipse's interface, templates have changed, bndtools tutorials doesn't seem to work, equinox doesn't seem to to work without felix, javafx8+osgi generate different kind of problems... etc.)
are too complex for a beginner (I just started to learn OSGi and Gradle) and they skip important steps I am not aware of
contain too much "IDE magic" (I would rather type some code instead of filling forms in eclipse)
some solve the problem with different tools (maven/tycho, bndtools, e(fx)clipse), but I've got no time to learn them
I want my application to be independent from IDE's environment. I don't want to use e(fx)clipse or BndTools if possible (even if they can make the build process easier)..
I'm experimenting with OSGi implementations, that's why I would rather not to choose between Equinox, Felix or Karaf.
I've already programmed similar application in .NET world, but it seems to me impossible to do the same in Java world..
My main questions are:
is it possible to do what I have imagined?
how to create a gradle multiproject what is IDE/platform independent (if projects are not tied to eclipse environment, or equinox, but it's possible to use them)?
what are the best ways to initialize the application (shell application + modules) and load the independent modules/bundles/components?
how to separate my views into subprojects (what build.gradle files should contain)?
how to solve the javafx8 inpompatibility with osgi?
what is the correct way to apply javafx plugin in gradle?
what tutorials are the most relevant?
is there any working example, pattern or tutorial (without using additional tools) what solve the same problem (using only osgi+javafx+gradle)?
I could group your questions in differents topic:
OSGI
You just need to google around to find out that is a java specification that encourages modularization, provides hot-deploy feature, and so on. As I told you, is just an specification like Java Servlet API, so they are different providers or implementers of OSGI Specification such as Felix and Equinox. Karaf instead is a OSGI container based on Felix, so you get all felix benefits and in addiction karaf natives features. For that reason I encourage you to take Karaf into use.
Aquote BndTool
In order to satisfy the OSGI specification, you need that your modules contains a MANIFEST.MF which holds all dependency information so Karaf create the classloader required for your bundles.
Assuming that you don't want to create that MANIFEST.MF files by hand, you could take aqute/bndtool for that. Don't get mess with bndtool for eclipse plugin. That application can be used from command line, from a maven plugin, or from a gradle plugin. Basically scans your classes, check the imports, and create a MANIFEST.MF automatically.
Gradle
If you choose gradle as a build tool, then you can take into use: Bnd Gradle plugin. It's easy to set up, but follow the instruction for non-workspace plugin. If you don't want to use BndTool for eclipse. IDE independent solution, you mentioned in your question.
MultiProject Layout
How the project layout should look like, depends on your modularization, but you can have a look on this layout example that uses gradle+osgi+karaf for a multiproject. Perhaps inspires you.
https://github.com/antoniomaria/gradle-karaf-bnd-project
I need to validate whether the imported packages of a bundle are fulfilled by a set of other bundles' export packages. This should not be very hard to implement but I know all the OSGi containers plus eclipse (when you do "validate bundles" in PDE) do this. I just don't know how to find that code. Does anyone know what classes/libraries I could use that already implement all this logic?
My goal is to give a list of files (bundles) in the file system and do an analysis whether the set of bundles is self-contained and if not to show all the missing external imports/requires. all this without actually having to run the bundles in a real container
You should look at the Resolver API in the OSGi spec. Apache Felix has a resolver implementation that is also used by the Equinox framework.
I'm new to osgi and really confused about how it all fits together. I want to create 3 bundles, an api bundle that defines an interface, a impl bundle that provides an implementation and another bundle that uses the implemenation using maven and the maven-bundle-pugin.
I need a bit of guidance:
do i need 3 maven projects?
does it help to/should i use a maven archetype for creating the projects?
do i need tu use maven-pax?
any other hints for a osgi newbie?
Thank you
I have written a tutorial some time ago that may contain what you need.
Some spoilers ..
Yes you should create three maven projects. Ideally also a parent project so you can build them in one command.
You can use an archetype but the easier way may be to just copy the example code and change it.
The tutorial shows how to deploy on Apache Karaf which imho is the easiest OSGi server to start with. Still the bundles produces during the build should also work in plain Felix or Equinox but the deployment will be a little harder.
I'm new to osgi and wonder if it is possible to have a centralized mechanism to update, install or remove bundles.
Yes. You can do this programmatically, which means there are a large number of bundles that provide you out-of-the-box solutions. It is so easy (and so much fun) that for many people one of their first bundles is a little "management agent" (as the OSGi specification calls this part).
The absolute simplest solution is Apache File Install. It tracks a directory and installs/uninstalls from there. Couple this to Google Drive or Dropbox and you have a large scale fully automated deploy model (it also handles configuration, which is quite important).
The OSGi specification now has an OSGi Bundle Repository (OBR) specification. This is a very powerful model to describe dependencies (not just bundles) that allow management agents to calculate/leverage dependencies. This is supported out of the box on Felix.
There are a myriad of solutions that manage OSGi frameworks. There is commercial support with Paremus, IBM Tivoli, ProSyst and many others. And open source with Apache ACE and fusebundles.
There are two general ways to do that: Have you application to 'pull' bundles from a repository hosting bundles and update itself, or have an external provisioning application 'push' bundles to your application.
For pull solutions I'd say there is:
Eclipse P2 Used by the update manager of Eclipse. Mature, stable, but can be a bit tricky to get into, also I'm not sure if P2 works with other OSGi runtimes than Eclipse Equinox
Apache Bundle Repository (OBR) A bit easier, and it's in the OSGi spec.
For push solutions I'd say have a look at Apache Ace, from your question I think that is closest to what you want to do.
There are a few options for developing modules for Netbeans 7.0.1 RCP. I haven't found any clear comparison of them.
So I would like to know which of them is the easiest to:
develop
install by user (e.g. user could choose proper jar with module
from a repository )
Which makes to write less non-reusable code (e.g. when you want to make web application of used classes later)?
Which is the most popular?
The easiest way is to use the traditional Netbeans way - build nbm's. This is well tested and good feature. After building module you will get the "nbm" file with all needed info inside (additional jars, settings, etc.)
You can use "Module Update" features from Netbeans.
The other way is to build modules as osgi bundles.
This feature was introduced in 6.7 version and up to now it has some problems.
First of all, bundle in normal understanding is one jar. If your bundle depends on other jar (f.e. apache-commons:beanutils), you will need to pack this jar into your bundle jar (using maven-bundle-plugin) or to install "beanutils" as independent bundle. The first solution is not the best, because if in the future another bundle wants to use "beanutils" you will need to link new bundle with old one, even if they don't need this. This cause high cohesion between modules. Or you can pack "beanutils" into your new bundle, but this can cause classloading issues in osgi-framework.
So, if you need to install netbeans module, you just install one nbm file and that's all.
If you need to install bundle, you need to install all dependent bundles separately beside yours bundle.
Another things are, for now you can't configure osgi-framework, which embedded in netbeans and process of loading bundles has some differences from loading standard netbeans modules which can cause some "strange" issues.
I'm sure that guys from netbeans will fix this issues and they are moving in right direction, but for now, if you don't need bundles, don't use it.