4.6. Provisioning
ServiceMix Kernel provides a simple, yet flexible, way to provision applications or "features". Such a mechanism is mainly provided by a set of commands available in the features
shell. The provisioning system uses xml "repositories" that define a set of features.
Repositories
The xml repositories use the following Relax NG Compact syntax:
element features { element feature { attribute name { text }, element feature { text }*, element config { attribute name { text }, text }*, element bundle { text }* }* }
Here is an example of such a repository:
<features> <feature name="nmr"> <bundle>mvn:org.apache.servicemix.nmr/org.apache.servicemix.nmr.api/1.0-SNAPSHOT</bundle> <bundle>mvn:org.apache.servicemix.nmr/org.apache.servicemix.nmr.core/1.0-SNAPSHOT</bundle> <bundle>mvn:org.apache.servicemix.nmr/org.apache.servicemix.nmr.osgi/1.0-SNAPSHOT</bundle> <bundle>mvn:org.apache.servicemix.nmr/org.apache.servicemix.nmr.spring/1.0-SNAPSHOT</bundle> <bundle>mvn:org.apache.servicemix.nmr/org.apache.servicemix.nmr.commands/1.0-SNAPSHOT</bundle> <bundle>mvn:org.apache.servicemix.nmr/org.apache.servicemix.nmr.management/1.0-SNAPSHOT</bundle> </feature> </features>
A repository includes a list of feature
elements, each one representing an application that can be installed. The feature is identified by its name
which must be unique amongst all the repositories used and consists in a set of bundles that need to be installed along with some optional dependencies on other features and some optional configurations for the Configuration Admin OSGi service.
Bundles
The main information provided by a feature is the set of OSGi bundles that defines the application. Such bundles are URLs pointing to the actual bundle jars. For example, one would write the following definition:
<bundle>http://repo1.maven.org/maven2/org/apache/servicemix/jbi/org.apache.servicemix.jbi.api/1.0-m1/org.apache.servicemix.jbi.api-1.0-m1.jar</bundle>
Doing this will make sure the above bundle is installed while installing the feature.
However, ServiceMix Kernel provides several URL handlers, in addition to the usual ones (file, http, etc...). One of these is the maven URL handler, which allow reusing maven repositories to point to the bundles. The equivalent of the above bundle would be:
<bundle>mvn:org.apache.servicemix.jbi/org.apache.servicemix.jbi.api/1.0-m1</bundle>
In addition to being less verbose, the maven url handlers can also resolve snapshots and can use a local copy of the jar if one is available in your maven local repository.
Dependant features
Dependant features are usefull when a given feature depends on another feature to be installed. Such a dependency can be expressed easily in the feature definition:
<feature name="jbi"> <feature>nmr</feature> ... </feature>
The effect of such a dependency is to automatically install the required jbi
feature when the nmr
feature will be installed.
Configurations
TODO
Commands
TODO
features addUrl http://svn.apache.org/repos/asf/servicemix/smx4/obr-repo/features-nmr-1.0-m1.xml features install nmr