OSGi

Deploying the FAST ESP Search API to CQ 5.5

This post is dedicated to any OSGi developer who has endured the pain of wrapping a third-party JAR in order to deploy it to an OSGi container.

In this post we will deploy the FAST ESP Java Search API to CQ 5. Since Microsoft does not provide an OSGi bundle for this API, we will create our own using the technique described on the CQ Blueprints post, Deploying 3rd Party Libraries.

The high-level approach is as follows:

  1. Download the FAST ESP Java Search API (version 5.3.0.6) from Microsoft Connect and upload it to your 3rd party Nexus repository. I assume that the readers of this post are familiar with Nexus and have their own repository.
  2. Create a Maven project to create the wrapped version of API.
  3. Deploy the wrapped version of the API to your Nexus repository.
  4. Deploy the wrapped version of the API to CQ via the Felix console.
  5. Add the wrapped version of the API as a dependency to your Maven project.
  6. Update your CQ instance to allow sun.io to be exported as part of the Felix system bundle from the framework classloader.

Adding a 3rd Party JAR (esp-searchapi.jar) to Nexus

It is recommended that you add a proxy repository to http://repository.opencastproject.org/nexus/content/groups/public/ as this repository has the Xalan and Xerces artifacts used by this article.

  1. Log in as the admin user to your Nexus repository (i.e., http://localhost:8081/nexus/)
  2. Select Repositories and click 3rd party repository.
  3. Click the Artifact Upload tab an enter the following information:

    GAV Definition:GAV Parameters
    Group:no.fast
    Artifact:esp-searchapi
    Version:5.3.0.6
    Packaging:jar

  4. Click the Select Artifact(s) to Upload… button and browse to the location of the FAST ESP Java Search API (i.e., esp-searchapi.jar).
  5. Once selected, click the Add Artifact button followed by the Upload Artifact(s) button.
  6. If successful, you should now have a vanilla version of the FAST ESP Java Search API that can be included as a dependency by Maven. This dependency will be used in the next step.

<dependency>
  <groupId>no.fast</groupId>
  <artifactId>esp-searchapi</artifactId>
  <version>5.3.0.6</version>
</dependency>

Create a Maven Project to Build the Wrapped JAR

Create the following POM. Please note: the dependencies listed in the POM below were defined by trial and error. I had many unsucessful deployments to Apache Felix with failed dependencies. In the end, the list of embedded dependencies included Xalan, Xerces and Log4j. Most of the remaining dependencies, such as HttpClient and javax.* packages were satisfied by Felix. Actually, the only dependency that was not satisfied was the sun.io package. I solved this by allowing Felix to export and load the sun.io packages from the framework class loader.

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

	<modelVersion>4.0.0</modelVersion>

	<groupId>no.fast</groupId>
	<artifactId>esp-search-api-wrapped</artifactId>
	<version>5.3.0.6</version>
	<packaging>bundle</packaging>

	<name>FAST ESP Search API</name>
	<description>An OSGi version of FAST ESP Search API</description>

	<properties>
		<esp-searchapi.version>5.3.0.6</esp-searchapi.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.apache.xalan</groupId>
			<artifactId>com.springsource.org.apache.xalan</artifactId>
			<version>2.7.1</version>
		</dependency>
		<dependency>
			<groupId>org.apache.xerces</groupId>
			<artifactId>com.springsource.org.apache.xerces</artifactId>
			<version>2.9.1</version>
		</dependency>
		<dependency>
			<groupId>log4j</groupId>
			<artifactId>log4j</artifactId>
			<version>1.2.15</version>
		</dependency>
		<dependency>
			<groupId>no.fast</groupId>
			<artifactId>esp-searchapi</artifactId>
			<version>5.3.0.6</version>
		</dependency>
	</dependencies>

	<build>
		<pluginManagement>
			<plugins>
				<plugin>
					<groupId>org.apache.felix</groupId>
					<artifactId>maven-bundle-plugin</artifactId>
					<version>2.3.5</version>
					<extensions>true</extensions>
				</plugin>
			</plugins>
		</pluginManagement>
		<plugins>
			<plugin>
				<groupId>org.apache.felix</groupId>
				<artifactId>maven-bundle-plugin</artifactId>
				<configuration>
					<instructions>
						<Import-Package>javax.*,sun.io.*,org.apache.commons.httpclient.*,org.apache.commons.logging.*</Import-Package>
						<Embed-Dependency>*;scope=compile|runtime</Embed-Dependency>
						<Embed-Directory>OSGI-INF/lib</Embed-Directory>
						<Embed-Transitive>true</Embed-Transitive>
						<_exportcontents>
							com.fastsearch.esp.search.*;version=${esp-searchapi.version}
						</_exportcontents>
					</instructions>
				</configuration>
			</plugin>
		</plugins>
	</build>
</project>

Run mvn clean install. This should produce a file called esp-search-api-wrapped-5.3.0.6.jar in your target directory.

Similar to before, upload this artifact to your 3rd party Nexus repository using the following:

GAV Definition:GAV Parameters
Group:no.fast
Artifact:esp-searchapi-wrapped
Version:5.3.0.6
Packaging:jar

You should now be able to use the new wrapped version of the API in your Maven POM by adding the following dependency.

<dependency>
  <groupId>no.fast</groupId>
  <artifactId>esp-searchapi-wrapped</artifactId>
  <version>5.3.0.6</version>
</dependency>

Deploy the esp-searchapi-wrapped-5.3.0.6.jar to CQ via the Felix console.

Lastly, edit yourcqinstance/crx-quickstart/sling.properties and add the following line. This will allow Felix to export sun.io and make it available from the framework classloader.

org.osgi.framework.system.packages.extra=sun.io

.

Once this change is made, restart CQ 5.

Apache Felix - Example 3 Continued: Testing Service Unregistration

 

Apache Felix Tutorial Example 3 walks the user through an implementation of a simple dictionary service. At the end of the tutorial, it describes a use case in which the dictionary service is unregistered. Under this scenario, the code in the example should throw a null pointer exception.

 I was curious how to force this use case and came up with the following additional steps to experiment with unregistering the service while the client was using it. We just need access to another shell so that we can have the client running in one shell, and stop the service in a second shell.

  1. Begin, by downloading the Remote Shell bundle under the subprojects section of the download page.
  2. Install and start the Remote Shell bundle. This will provide remote access to the Felix shell via Telnet.
    start file:/path/to/download/org.apache.felix.shell.remote-1.1.2.jar
  3. Open your preferred Telnet application, such as putty, and set the port to 6666 and the host to localhost.
  4. In your original shell (not the remote) start the example 3 client.
    g! lb | grep Client
    START LEVEL 1
    ID|State |Level|Name
    12|Resolved | 1|Dictionary Client (1.0.0)
    g! start 12
    Enter a blank line to exit.
    Enter a word:
    testing
    No match found!
  5. Find the ID of the English dictionary service and stop it.

    g! lb | grep English
    10|Resolved | 1|English dictionary (1.0.0)
    g! stop 10
  6. Lastly, go back to the shell running the dictionary client and enter a new word. You should now receive a null pointer exception!
    Enter a word:
    testing2
    org.osgi.framework.BundleException: Activator start error in bundle [12].
    at org.apache.felix.framework.Felix.activateBundle(Felix.java:2027)
    at org.apache.felix.framework.Felix.startBundle(Felix.java:1895)
    at org.apache.felix.framework.BundleImpl.start(BundleImpl.java:944)
    at org.apache.felix.gogo.command.Basic.start(Basic.java:729)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.felix.gogo.runtime.Reflective.invoke(Reflective.java:137)
    at org.apache.felix.gogo.runtime.CommandProxy.execute(CommandProxy.java:82)
    at org.apache.felix.gogo.runtime.Closure.executeCmd(Closure.java:477)
    at org.apache.felix.gogo.runtime.Closure.executeStatement(Closure.java:403)
    at org.apache.felix.gogo.runtime.Pipe.run(Pipe.java:108)
    at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:183)
    at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:120)
    at org.apache.felix.gogo.runtime.CommandSessionImpl.execute(CommandSessionImpl.java:89)
    at org.apache.felix.gogo.shell.Console.run(Console.java:62)
    at org.apache.felix.gogo.shell.Shell.console(Shell.java:203)
    at org.apache.felix.gogo.shell.Shell.gosh(Shell.java:128)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.apache.felix.gogo.runtime.Reflective.invoke(Reflective.java:137)
    at org.apache.felix.gogo.runtime.CommandProxy.execute(CommandProxy.java:82)
    at org.apache.felix.gogo.runtime.Closure.executeCmd(Closure.java:477)
    at org.apache.felix.gogo.runtime.Closure.executeStatement(Closure.java:403)
    at org.apache.felix.gogo.runtime.Pipe.run(Pipe.java:108)
    at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:183)
    at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:120)
    at org.apache.felix.gogo.runtime.CommandSessionImpl.execute(CommandSessionImpl.java:89)
    at org.apache.felix.gogo.shell.Activator.run(Activator.java:75)
    at java.lang.Thread.run(Unknown Source)
    Caused by: java.lang.NullPointerException
    at com.gastongonzalez.felix.tutorial.example3.Activator.start(Unknown Source)
    at org.apache.felix.framework.util.SecureAction.startActivator(SecureAction.java:641)
    at org.apache.felix.framework.Felix.activateBundle(Felix.java:1977)
    ... 32 more
    java.lang.NullPointerException

Apache Felix - Bundle Installation and NoClassDefFoundError

 

I am on day two of a long journey to master OSGi. As such, I have been working through the OSGi tutorials on the Apache Felix site. As I continue down this path, I thought I would document the issues that I encounter as a novice, hopefully, helping others at my same level.

This afternoon, I tried installing a new bundle (felix-tutorial-example5.jar) and received a java.lang.NoClassDefFoundError exception for the ServiceTracker class. As it turns out, I forgot to import the org.osgi.util.tracker package in my manifest. So next time you receive a NoClassDefFoundError exception when installing a bundle, check that you have all of your import packages defined.

The Solution:

Import-Package: org.osgi.framework, 
org.osgi.util.tracker,
com.gastongonzalez.felix.tutorial.example2.service

The Problem:

g! felix:start file:/c:/temp/felix-tutorial-example5.jar
org.osgi.framework.BundleException: Activator start error in bundle [28].
at org.apache.felix.framework.Felix.activateBundle(Felix.java:2027)
at org.apache.felix.framework.Felix.startBundle(Felix.java:1895)
at org.apache.felix.framework.BundleImpl.start(BundleImpl.java:944)
at org.apache.felix.gogo.command.Basic.start(Basic.java:729)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.felix.gogo.runtime.Reflective.invoke(Reflective.java:137)
at org.apache.felix.gogo.runtime.CommandProxy.execute(CommandProxy.java:82)
at org.apache.felix.gogo.runtime.Closure.executeCmd(Closure.java:477)
at org.apache.felix.gogo.runtime.Closure.executeStatement(Closure.java:403)
at org.apache.felix.gogo.runtime.Pipe.run(Pipe.java:108)
at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:183)
at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:120)
at org.apache.felix.gogo.runtime.CommandSessionImpl.execute(CommandSessionImpl.java:89)
at org.apache.felix.gogo.shell.Console.run(Console.java:62)
at org.apache.felix.gogo.shell.Shell.console(Shell.java:203)
at org.apache.felix.gogo.shell.Shell.gosh(Shell.java:128)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.apache.felix.gogo.runtime.Reflective.invoke(Reflective.java:137)
at org.apache.felix.gogo.runtime.CommandProxy.execute(CommandProxy.java:82)
at org.apache.felix.gogo.runtime.Closure.executeCmd(Closure.java:477)
at org.apache.felix.gogo.runtime.Closure.executeStatement(Closure.java:403)
at org.apache.felix.gogo.runtime.Pipe.run(Pipe.java:108)
at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:183)
at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:120)
at org.apache.felix.gogo.runtime.CommandSessionImpl.execute(CommandSessionImpl.java:89)
at org.apache.felix.gogo.shell.Activator.run(Activator.java:75)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NoClassDefFoundError: org/osgi/util/tracker/ServiceTracker
at com.gastongonzalez.felix.tutorial.example5.Activator.start(Unknown Source)
at org.apache.felix.framework.util.SecureAction.startActivator(SecureAction.java:641)
at org.apache.felix.framework.Felix.activateBundle(Felix.java:1977)
... 32 more
Caused by: java.lang.ClassNotFoundException: org.osgi.util.tracker.ServiceTracker not found by[28]
at org.apache.felix.framework.BundleWiringImpl.findClassOrResourceByDelegation(BundleWiringImpl.java:1460)
at org.apache.felix.framework.BundleWiringImpl.access$400(BundleWiringIm
pl.java:72)
at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.loadCla
ss(BundleWiringImpl.java:1843)
at java.lang.ClassLoader.loadClass(Unknown Source)
... 35 more
java.lang.NoClassDefFoundError: org/osgi/util/tracker/ServiceTracker