When I tried to use reference:file:/path/to.jar as a bundle URL in Karaf integration tests, I got "Unknown protocol: reference" errors. There are some mentions of reference: URLs on Karaf mailing list, but this isn't clear to me:
Should they work by default?
If not, how do I enable them? Presumably I need a suitable bundle providing URLHandlerService, but which one?
The URL handlers in Karaf are provided by the Pax-Url project, I don't think the reference one is provided by default (as primarily for test support).
You can find pax-url-reference via maven here
Related
I'm creating a Liferay 7.1 OSGi bundle, which has some external dependencies in it. In consideration of time, we opted to embed the external JAR in our OSGi Bundle. I've managed to create a bnd file, which includes all of the ElasticSearch dependencies, and put them on the bundle classpath. I've used the source-code from github (https://github.com/liferay/liferay-portal/blob/master/modules/apps/portal-search-elasticsearch6/portal-search-elasticsearch6-impl/build.gradle) and the bnd.bnd file, to check what's imported.
When activating the bundle, an exception is thrown:
The activate method has thrown an exception
java.util.ServiceConfigurationError: org.elasticsearch.common.xcontent.XContentBuilderExtension: Provider org.elasticsearch.common.xcontent.XContentElasticsearchExtension not a subtype
at java.util.ServiceLoader.fail(ServiceLoader.java:239)
at java.util.ServiceLoader.access$300(ServiceLoader.java:185)
at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:376)
at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:404)
at java.util.ServiceLoader$1.next(ServiceLoader.java:480)
at org.elasticsearch.common.xcontent.XContentBuilder.<clinit>(XContentBuilder.java:118)
at org.elasticsearch.common.settings.Setting.arrayToParsableString(Setting.java:1257)
The XContentBuilderExtension is from the elasticsearch-x-content-6.5.0.jar,
the XContentElasticsearchExtension class, is included in the elasticsearch-6.5.0.jar. Both are Included Resources, and have been put on the classpath.
The Activate-method initializes a TransportClient in my other jar, hence it happens on activation ;).
Edit:
I've noticed that this error does NOT occur when installing this the first time, or when the portal restarts. So it only occurs when I uninstall and reinstall the bundle. (This is functionality I really prefer to have!). Maybe a stupid thought.. But could it be that there is some 'hanging thread'? That the bundle is not correctly installed, or that the TransportClient still is alive? I'm checking this out. Any hints are welcome!
Edit 2:
I'm fearing this is an incompatibility between SPI and OSGi? I've checked: The High Level Rest Client has the same issue. (But then with another Extension). I'm going to try the Low-Level Rest Client. This should work, as there are minimal dependencies, I'm guessing. I'm still very curious on why the incompatibility is there. I'm certainly no expert on OSGi, neither on SPI. (Time to learn new stuff!)
Seems like a case where OSGi uses your bundle to solve a dependency from another bundle, probably one that used your bundle to solve a package when the system started.
Looking at the symptoms: it does not occur when booting or restarts. Also it is not a subtype.
When OSGi uses that bundle to solve a dependency, it will keep a copy around, even when you remove it. When the bundle comes back a package that was previously used by another bundle may still be around and you can have the situation where a class used has two version of itself, from different classloaders, meaning they are not the same class and therefore, not a subtype.
Expose only the necessary to minimize the effects of this. Import only if needs importing. If you are using Liferay Gradle configuration to include the bundle inside, stop - it's a terrible way to include as it exposes a lot. If using the bnd file to include a resource and create an entry for the adicional classpath location, do not expose if not necessary. If you have several bundles using one as dependency, make sure about the version they use and if the exchange objects from the problematic class, if they do, than extra care is required.
PS: you can include attributes when exporting and/or importing in order to be more specific and avoid using packages from the wrong origin.
You can have 2 elastic search connections inside one Java app and Liferay is by default not exposing the connection that it holds.
A way around it is to rebuild the Liferay ES connector. It's not a big deal because you don't need to change the code only the OSGi descriptor to expose more services.
I did it in one POC project and worked fine. The tricky thing is to rebuild the Liferay jar but that was explained by Pettry by his google like search blog posts. https://community.liferay.com/blogs/-/blogs/creating-a-google-like-search (it is a series but it's kind of hard to navigate in the new Liferay blogs but Google will probably help) Either way it is all nicely documented here https://github.com/peerkar/liferay-gsearch
the only thing then what needs to be done is to add org.elasticsearch.* in the bnd.bnd file in the export section. You will then be able to work with the native elastic API.
I am able to get OSGi blueprint to work in Karaf, but I don't understand how to do it in Apache Felix, or my question can be also defined as how can I use OSGi blueprint in plain OSGi?
I made an example here https://github.com/PhilAndrew/sbt-osgi-felix-akka-blueprint-camel using https://github.com/doolse/sbt-osgi-felix in which Akka is working but Blueprint and Camel not yet working.
This question may help Is Apache Aries running in Felix?
It's not starting Blueprint because your bundle's code doesn't actually rely on any of the classes in blueprint, so you either need to add "Require-Bundle" header to your manifest:
requireBundle := Seq("org.apache.aries.blueprint")
or add the bundles that needed to be started to the osgiDependencies of run:
osgiDependencies in run := bundleReqs("org.apache.aries.blueprint.core",
"org.apache.aries.proxy")
Apache Karaf also runs on felix. So for the most part you just need to install the correct bundles and maybe do the necessary system package exports if you hit package use constraint violations.
Check what karaf installs and try to do the same.
For publishing with SSL using the Endpoint I need to access classes under the packages com.sun.net.httpserver.*
Using the Eclipse IDE I found a way to use this classes. But exporting the bundles and running them in another equinox OSGi Installation I can't start the bundle throwing the following error:
java.lang.NoClassDefFoundError: com/sun/net/httpserver/HttpsConfigurator
Anyone an Idea how to solve this issue?
Thanks!
The package you're referring to is part of the JDK. You need to expose it, to make it available in OSGi and you have two options:
The first, and in most cases preferred option, is to expose this package through the system bundle. The OSGi framework has a property that you can set to do this:
org.osgi.framework.system.packages.extra=...
As its value, you provide it with a comma separated list of packages that you want to expose, on top of the ones that are already exposed by the framework. In your case, at least com.sun.net.httpserver, but there might be more packages that you need. In this case, also make sure that the bundle that uses this package imports this package.
The second option is to use a mechanism used boot delegation. It should only be used as a last resort, as it breaks modularity and if it's not used carefully it might lead to other problems. Again, this is a property that you need to set:
org.osgi.framework.bootdelegation=*
Here, you can provide a comma separated list of packages that should be loaded by the boot class loader. Wildcards are supported (as seen in the example above) but you are encouraged to be as specific as possible, so in your case for example use com.sun.* as the value.
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.
We run Restlet 2.1 in an OSGi environment (Equinox) as bundle (ie. not as library within a bundle). The problem is that the Restlet Engine does not detect helpers (like converters) that are provided by Restlet extensions. Specifically, the EngineClassLoader#getResources() call does not return any result. The extensions are also deployed as OSGi bundles in the target platform.
Is automatic converter registration actually supposed to work within OSGi environments?
In fact, Restlet supports such feature thanks to a dedicated activator (see the Activator class in the package org.restlet.engine.internal).
This activator introspects bundles to find out the following things:
servers corresponding to registered servers
servers corresponding to registered clients
authenticators corresponding to registered clients
converters
Be aware that to use this feature, we must use the OSGi edition of Restlet since it's the only that has the MANIFEST file of the org.restlet bundle with the activator class specified. Otherwise you don't have to care about the bundle loading order...
Hope it helps you.
Thierry
Unless the Restlet-bundle explicitly imports the packages that contain the extensions (and I doubt it does, and it shouldn't), it wouldn't be able to load them, because bundles have isolated class-spaces.
A possible solution would be to provide the extensions as fragments attached to the Restlet-bundle. Thus, if you make it use the bundle-classloader (the documentation says this can be done by setting the Engines classloader), it would be able to load classes from the fragments.
Indeed it doesn't quite work for OSGi, as it depends on the ability to see the entire class space.
The way to do this in OSGi would be to use the service registry for the extensions, but that only works for OSGi aware libraries.
There is some help on the way: In the recently released OSGi 5 (Service Loader Mediator) there will be support to 'bridge' META-INF/services (I don't know if Restlet uses those, though) onto OSGi services, so 'legacy' libraries should work well within OSGi.
There is an implementation in Apache Aries called Spi-Fly. I looked at it briefly a while back. It might do the trick for you, it might not.