Difference between revisions of "Equinox/p2/Webapp QuickStart"

Revision as of 18:23, 29 April 2008

Quickstart - Using Equinox Provisioning in a Web Application

The Equinox provisioning work has in the past been used to demonstrate its use deploying rich client applications however it’s equally relevant for server-side applications. This Quickstart will provide a WAR file that is an amalgamation of the servletbridge and new provisioning work. The servletbridge handles the launching of Equinox and provides a conduit for HTTP requests but is otherwise not involved in the management of bundles running in an installation. As compared with the current release (3.3) the way we’re going to manage the installation of bundles is significantly different and we'll demonstrate the new provisioning work by installing new functionality into an exisiting server application.

What you’ll need….

1) A servlet container (I suggest the latest version of either Tomcat or Jetty). We’re going to be using the OSGi console so it would simplify things if you can use StdIn/Out. If not you will have to tweak the web.xml to use a remote port.

2) Provisioning WAR file -- provbridge.war In Eclipse 3.3, the update configurator bundle (org.eclipse.equinox.update.configurator) would traverse your eclipse/plugins directory and install all bundles it found. For this quickstart we’re going to do things a little differently. Rather than just installing everything the provisioning work will generate a metadata repository to represent the various requirements and capabilities of each bundle.

3) JSP Sample Repository WAR file -- metajsp.war For the purposes of this quickstart we’re going to install this WAR file in the same Servlet container however it’s meant to represent a remote metadata repository similar to an Eclipse Update site.

Instructions…

1) Install the two WAR files in your Servlet container and start it up. (e.g. in Tomcat place copy the two WAR files to your webapps directory and run bin/startup.bat or bin/startup.sh)

2) The OSGi console should start automatically and you should see the OSGi prompt (e.g. “osgi>”). At the prompt type “ss” to see the list of the bundles that makes up our base provisioning agent.

Note: You might notice the org.eclipse.equinox.prov.selfgenerator is STARTING. This bundle produces the initial metadata repository and profile that describes the contents of the plugins folder and the software currently installed. After it’s STARTED we’re ready to proceed. You should see the following status message "Status OK: org.eclipse.equinox.prov code=0 null"

3) Let’s add a metadata and artifact repository so we can provision some new functionality Type “?” to list the console commands. You should see a number of the new provisioning commands.

Type the following in the console:

• provaddartifactrepo http://localhost:8080/metajsp/artifactRepository/artifacts.xml
• provaddrepo http://localhost:8080/metajsp/metadataRepository/

You can use the “provlr” and “provlar” commands to examine the contents of the repositories if you like.

• provlr http://localhost:8080/metajsp/metadataRepository/

4) The repositories contain the metadata for adding JSP support and a simple helloworld example. Let’s install into our current profile.

First let's examine our current profile. The IUs prefixed with "self" are called IUFragments and provide configuration information for there like name IU host.

• provlp eclipse.prov.profile.current
  • This displays nothing under Jetty 6.1.9 and following the above - Alex

Next let's install our new functionality and take a look at what's changed

• provinstall sample.jsp 1.0.0 eclipse.prov.profile.current
  • Doesn't work either - Alex
  • provinstall sample.jsp 1.0.0 eclipse.prov.profile.current
  • java.lang.IllegalArgumentException: URI has an authority component
  • at java.io.File.<init>(File.java:340)
• provlp eclipse.prov.profile.current
  • Same as above Apr08

What you should see is that in addition to sample.jsp all of it's dependencies have been added. In this case javax.servlet.jsp the jasper engine and it's dependencies.

5) The change is in our current profile now, so let's enable the change.

• confapply

6) Type ss to view the newly installed JSP bundles. You can now visit http://localhost:8080/provbridge/helloworld.jsp to see the JSP page you’ve just provisioned.