Skip to main content

Some useful OSGI commands to dig in to issues with deployed bundles deployed in WSO2 products

WSO2 Products developed on top of the core WSO2 Carbon platform.WSO2 Carbon is a componentized Service Oriented Platform(SOA) which is built on OSGI framework,which defines a dynamic component system for Java.Bundle is the unit of modularization in OSGI. 
If I described on how a WSO2 product is created ,first there are a set of components introduced and implemented as OSGI bundles.You can find such developed set of components from here.Then we group a set of components as a feature.And there are such pre-defined features which can be found from here.Then with selecting a relevant set of features,the product have been built.For example this pom.xml under the svn location contains the features set used by the product WSO2 API Manager product.And most importantly,one more advantage of this approach is at later time,product can be customize by adding more  features from wso2 feature manager at runtime.

The main focus of this blog post is to guide on some OSGi level commands that would help to identify issues,when a user tries to deploy an OSGI bundle into a WSO2 product. Most common error the developers are facing,is CNF [Class Not Found] error-Though the OSGI bundle deployed to product,the classes exposing from that particular bundle is not available to OSGI runtime and thus CNF will be thrown.

For such instances,following steps will help you to identify the root-cause of the issue. 
  1. First start the server with  enabling OSGI console available- ./wso2server.sh -DosgiConsole
  2. Then list the available bundles of the server by trying the OSGI command  -  "ss package_name_of_bundle". For get list of commands try the command 'help'.
  3. You'll notice particular bundle will be in 'INSTALLED' state according to OSGI life-cycle.[Not in 'ACTIVE' state]
  4. Try diagnosing the particular bundle with the command "diag bundle_id" [Here bundle_id is the id retrieved for the bundle from above 2nd step]
  5. Once you tried,above you'll see about the un-satisfied  constraints on the specific bundle.In other word,that particular bundle has not become as an active bundle,due to an unsatisfied dependency which is referring from the bundle.
  6. Most of the time,the unsatisfied constraint is a dependency which is imported by the spefic bundle,but from no where else that dependency has export to OSGI runtime,thus unable to find that dependency available in runtime to import and use with the bundle.You can check this by the command 'p packageNameOfUnsatisfiedDependency'.This command will list  the places where the dependency imported and exported.
  7. If the result of above 6,is like no entry about exported places,then we need to add that dependency to OSGI runtime by exporting it from same bundle or from a separate bundle. Or if the package name of that dependency is available as a public JDK package,then you can export it via System bundle by adding an entry for the package name of the dependency to launch.ini file [which can be found from {Product_Home}/repository/conf/etc]

Comments

Post a Comment

Popular posts from this blog

Convert an InputStream to XML

For that we can use DocumentBuilder class in java. By using the method parse(InputStream) ; A new DOM Document object will return. InputStream input; DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder parser = factory.newDocumentBuilder(); Document dc= parser.parse(input); In the above code segment,by using the created Document object,the corresponding XML file for the inputStream can be accessed. References: http://www.w3schools.com/dom/dom_intro.asp http:// download.oracle.com/javase/1.4.2/docs/api/javax/xml/parsers/DocumentBuilder.html
2 comments
Read more

CORS support from WSO2 API Manager 2.0.0

Cross-origin resource sharing (CORS) is a mechanism that allows restricted resources  on a web page to be requested from another domain outside the domain from which the first restricted resource was served. For example, an HTML page of a web application served from http://domain-a.com makes an <img src >  request for a different domain as 'domain-b.com' to get an image via an API request.  For security reasons, browsers restrict cross-origin HTTP requests initiated from within scripts as in above example and only allows to make HTTP requests to its own domain. To avoid this limitation modern browsers have been used CORS standard to allow cross domain requests. Modern browsers use CORS in an API container - such as  XMLHttpRequest  or Fetch - to mitigate risks of cross-origin HTTP requests.Thing to  note is it's not only sufficient that the browsers handle client side of cross-origin sharing,but also the servers from which these resources getting need to handl
Post a Comment
Read more

[WSO2 AM] APIStore User Signup as an approval process

In previous versions of WSO2 APIManager before 1.6.0, it was allowed any user who's accessible the running APIStore come and register to the app.But there will be requirement like,without allowing any user to signup by him/her self alone,first get an approve by a privileged user and then allow to complete app registration.Same requirement can be apply to application creation and subscription creation as well.To fulfill that,we have introduced workflow extension support for  WSO2 APIManager  and you can find the introductory post on this feature from my previous blog post on " workflow-extentions-with-wso2-am-160 " . From this blog-post,I'll explain how to achieve simple workflow integration with default shipped resources with  WSO2 APIManager 1.6.0 and WSO2 Business Process Server 3.1.0 with targeting "user-signup" process. Steps First download the WSO2 APIManager 1.6.0[AM] binary pack from product download page . Extract it and navigate to
Post a Comment
Read more